Conference vmszoo::rc

    
    	Back the high speed needle valve out to three turns and change
    the glowplug. I have had/seen fox's that go belly up because of
    lean runs and also some leakage around the center post.  These
    changes should get the engine started and running. From there you
    can lean it out to get your high speed needle setting.
    
    						Tom

      You might also check your low speed valve... I had an O.S. 25
    that had acted quite the same as yours, and that was the problem.
    It loaded up on the ground and quit in the air after leaning out.
    If you still have your manual, it should tell you how many turns
    to open it(Make sure the throttle is all the way closed when adj)
    
    	Also, do yourselfe a favor and get rid of the Blast!! I 
    changed to Red Max this spring(from Blast) and my engines run
    MUCH better.  I use premium 10% nitro.  
    
    Good luck... Engine trouble can really be an annoyance!
    
    /Brian

    Jim,
    
    I had a lengthy reply all typed out for you but, for the second
    time this week, the system refused to add my reply:  error message
    said something like "SYSTEM PARTNER FAILED TO LINK" ??  What's going
    on I wonder?
    
    Anyhow, lemme' add my 2-cents worth.  I'll defer to Tom and Brian
    as regards direct knowledge of your particular engine and second
    the motion that you try a new plug and fresh/different fuel.  You
    may have to try it with the sleeve in BOTH positions to prove any-
    thing since you're now uncertain which was is correct.  Let me just
    add that fuel DOES go bad with age but it has NOTHING to do with
    loss of nitro....any engine )except for a highly altered HOT-DAWG
    racing engine) will run just fine without nitro.  The main reason
    it's added to glo-fuel (in the USA only) is as an "igniter" which
    causes the mixture to burn a little hotter, keeping the plug hotter
    in turn and, thereby, giving you a more reliable idle.  Of course
    a few extra "R's" are gained in the process but, in a "normal" en-
    gine, nitro is NOT essential to whether or not the engine runs. 
    
    Please permit me to make a coupla' suggestions regarding engine
    tear-downs:  1.) Unless the engine has ingested an enormous quan-
    tity of contamination (dirt), NEVER tear an engine completely down.
    You can clean it just fine by removing the head, backplate and carb
    ONLY!  Just slosh it around in HOT, dish-soapy water while simul-
    taneously rotaing the crank. Then put the parts on a paper towel
    to drain and air-dry.  I don't recommend force-drying with heat
    as heat tends to promote RUST.  Reassemble using a GOOD quality
    oil (like Hoppe's gun oil) and use it libreally, especially on the
    bearings.  If I don't get a dense blue cloud of smoke the first
    time I run the engine, I figger' I was too stingy with the oil.
    Incidentally, WD-40 is an excellent rust-chaser but it leaves little
    or no residual oil so, if you use WD, be sure to follow-up with
    plenty of good oil like Hoppe's.
    
    If forced to totally disassemble an engine to replace a damaged/broken
    part, take your time...pay attentin to any/all parts that can
    potentially be assembled.  Use a scribe to make alignment marks
    BEFORE removing head-from-cylinder, sleeve-from-cylinder and rod-
    from-crankpin.  Also note position of the baffle atop the piston
    (if your engine has one).  These simple steps will save you a LOTTA'
    grief when reassembling and when complete, you'll KNOW it's RIGHT!
    
    Don't forget that things have to re-seat themselves now so treat the
    engine like a new one...run it a little rich for a few flights so
    the disturbed parts have a chance to wear-in again.
    
    Hope some of this helps, now or in the future.  These little mills
    are precision instruments and need to be treated and cared for as
    such.
    
    Adios,	Al

    Thanks Al, and the rest of you for the help. The weekends here and
    I'll give it another shot. Someone had mentioned a small "o"ring
    somewhere in the needle valve, could someone elaborate on this if
    in fact it does exist? Another question I have concerns port timming
    , does this only apply to shnurled (spelling) ported engines?Another
    thing was explained to me about the high speed and idle adjustment
    screws, they said one effects the other, could someone further this
    statement. Thanks again for any help you people are able to give.
                                               
                                                 baffled in boston

Jim,

As you say many comments have been made as to the correct way to reassemble an 
engine in previous notes, it would be worth your while reading them. I will 
make some comments that may help.

>   carb. what I did find was that the con. rod was worn at the top
>   where the wrist pin goes through. This item was replaced, the engine

It is a common fallacy that the Con-Rod should be a tight fit. I actually put a 
tapered reamer through the rod bush to give more clearance and ensure 
lubricants reach the bearing. Remember all the rod does is follow the crank and 
move the piston up on compression and force the crank down on the combustion 
stroke. A tight fit is not necessary for optimum performance. I don't recommend 
this be tried by inexperienced users, strictly for those who know what they are 
doing. You should also note there is a correct way found for the con rod. The 
side with the beveled big end goes towards the crank shaft.

>    lean. I then took the engine home and opened it up again (someone
>    had ask if I put the sleeve in backwards and thought I'd better
>    check) It look as though the intake port was closing first allowing
>    fuel to esape before compression (fuel from the exaust makes you
>    think rich, right) when actually it was being starved (my guess)
>    which would explaine the over heating. For the heck of it I turned
>    the sleeve so the exaust closes first, replaced the glow plug and
>    tryed again. It dose seem to run better but only with the glow clip

It is normal for the exhaust to close after the induction ports, this allows 
boost to be obtained when a tuned pipe is used. (See the note on engine tuning)

John

A glow plug can be bad even though it glows.  But for the
circumstances you're under -- a brand new engine -- you can
assume the plug is good if it shows red when the battery is
applied.

What you're really up against is inexperience and a brand new
engine. They are awfully touchy at the beginning when the parts
are still tight and the needle valve has not been set; it does
get much better.  Each engine has a little personality in that it
likes a certain way you do the starting procedure; you get to
learn this over time.

For instance, my OS .25 likes to be flipped about a half dozen
times with the batery disconnected; the K&B .20 thinks this is
poison; it likes to be turned over a couple of times then flipped
two or three times more with your finger over the carb opening.

I'd venture that even two engines of the same make will like
different treatment.  This comes with time as you get to know
your engine.

Also, though, it takes some time with these glow engines to know
them.  I would now ordinarily go into a tirade about how ignorant
the local engine experts are of the subject; but given your
circumstances (I detect a man going down for the third time), I'd
say to take the engine out to the nearest club field and ask
questions.  Don't take it to a hobby shop.  What you need is to
have someone fiddle with your live engine; the guy behind the
counter will only give advice.

This is one of the few instances where I think field advice is
preferable to hobby shop advice. Both are however, preferable to
any of my advice!

  I have a few questions about my engine setup...



   I have an OS .40 FP with a Snuffler muffler in my Wot 4 (I had an extension
tube on the exhaust pipe to divert the glow glop but took it off for tuning
purposes)


  I am having a hell of a time trying to get this setup to run right.  It seems
to always be too rich or too lean.  If it flies well at a setting for one
flight, the next flight might lean out.

  Here are a couple of observations I made yesterday.

    o With the engine at full throttle I adjusted the needle valve to max
      rpm's.  I held the plane in a nose up attitude to see if it would
      lean out and it was fine.  Within seconds after takeoff the engine
      sagged and I had to land.

   o I then richened the needle valve a couple of clicks and had the same 
     results.

   o Then I opened the needle valve 1 1/2 turns to find no change in engine
     speed.  It did not appear to richen the mixture.  I tried it there anyway
     and had a great flight.

  o The next attempt I couldn't get the plane off the ground because I had
    not power (too rich).

  o So I leaned it out about 3/4 of a turn and got a decent flight (it was the
    last of the day so I don't know if it will continue to run well).

  o If I do a loop or a snap roll I loose power for about 3 seconds.  It really
    sags!  This could get me in trouble!


  o The clunk is not stuck in the front of the tank.  There are no kinks in
    the fuel lines.  The engine is new (about 3 dozen flights on it) and has
    never been in a crash (other than a cartwheel).


  So.....does anyone know how to set up an engine with a Snuffler on it?  I have
not run the engine with the stock "muffler", ever.  So I don't know if it is
strictly a Snuffler setup problem.


               Thanks,


                           Jim

Jim, replace the glow plug with a K&B plug and run the engine
at just above the 4-cycle/2-cycle break point.  Engines not only
unload in the air, they also lean out, a factor often neglected
in setting them up.  Also, the new .40FP is ABC and does not lose
compression/power when it heats up due to being lean.  This used
to save us the glow plug, now it wrecks them on the first lean
run.  I've been there.

For what it's worth, I had similar problems with my .40FP last year (non-ABC,
no Snuffler). The mixture setting kept moving around. It turned out I had gunk
in the needle valve. Flushing the valve and installing a fuel line filter solved
the problem. 

Dave

  I did forget to mention that I did replace the glow plug after the 4th flight
with a K&B plug.  No difference.

  If I have the engine too rich then I don't have enough power for takeoff.


             Jim

  Dave,

  I'll check the needle valve tonight.  I don't know why I didn't think of
that.  A clogged spray hole would certainly make it tough to adjust the mixture.



        Thanks,

                       Jim

    Jim,
    	
    	Also check the vent line to the tank. Blow through it to make
    sure it's clear. I was having a similar problem with the Fiesta
    awhile back and it turned out the foam I had on top of the tank
    was forcing the tank down on top of the brass vent tube inside the
    tank. Not getting tank pressure, it would run fine for the normal
    checkout on the ground, then lean out in the air.
    
    Steve

Dirt in the fuel would be my number one guess; after that I would guess on a 
tank positioning problem. I would be interested to know if you are running any 
muffler pressure as it pressure could be a fix. What pressure does 
is to increase the fuel flow as the RPM increases and effectively improves 
needle margin.

> in setting them up.  Also, the new .40FP is ABC and does not lose
> compression/power when it heats up due to being lean.  This used
> to save us the glow plug, now it wrecks them on the first lean
> run.  I've been there.

Some how people have the idea that ABC is bad. I don't want to appear agro but 
that is further from the truth than you can imagine. ABC is the best thing to 
happen to engines.

For 2 strokes ABC is the answer. I am not flaming but lets finally stop this 
crap about "the problem with ABC's". I would never recommend anybody buy a 
ringed 2 stroke. 

John

  Well I got side tracked last night and didn't get a chance to look at my
engine.  With a little luck I'll get to it tonight (I might be going to
the Heart <Ann and Nancy Wilson> concert at Great Woods! The best part is
the tickets are free!!!!!).  I am using a brand new bottle of fuel so I 
wouldn't expect dirt there, but I'll check the tank for crap.


                 Jim

John, I'm sorry that I gave the impression that I'm rapping the
.40 ABC, and ABC's in general. What I've been trying to say is
that we have to treat them differently than we did the old lapped
piston.

Where with the lapped engines we could set them "a couple of
clicks rich" and be done with it, the ABC needs to be set much
richer, at just slightly above the point were it breaks into
2-cycle.  The problem is compounded because the field wisdom
hasn't caught up to this one yet and it disguises itself as many,
many things like tank position, pressure, dirt, etc.  What's
worse is that changing one of these things improves the situation
slightly for a short time and makes you think you've fixed the
problem.

I think it does this because the plug only typically goes
slightly bad (deep inside the element), and improving the fuel
flow/mixture makes it run better for a short time.  But the
bottom line is that the plug is sour and needs to be replaced.

I've followed Clarence Lee's column through my back issues of RCM
over its 20 or so years, and there's one thing he's been
consistent on: one lean run and you've ruined the glow plug if not
damaged/ruined the engine.

I've found that even a short leaning out on an engine with a
severe taper fit on the piston like my infamous K&B (its taking a
rest now btw) will screw the plug -- I mean nothing more than the
act of tweaking it in too far for a few seconds while adjusting
it.  This starts the chain of events that has had me buying new
fuel and getting frustrated at field advice for the last 3 years.  

John, against your knowledge of engines, I feel like a babbling
kid -- if you tell me I'm full of bull, that's what I am...but
I'll keep on believing this because it's consistent with
everything I've experienced.

Also, when I lay down my model bucks for an engine, you better
believe the ABC's will get my buy.  Though my experience to date
has shown that they are fussier, run hotter, and have no real
advantage in power over the lapped piston engine.  My lapped
piston Fox .36 puts out lots, lots, more power than the .40FP
(and runs cold as a cucumber), and my old lapped OS .25 is
nothing short of fantastic.

I cannot explain the above and continue to think that any day now
the .40 FP will live up to its ABC promise.

    Re: .-1, John T.,
    
    I can't imagine what yer' personal situation might be nut let me assure
    you that an ABC engine puts out _gobs_ more power than a like ringed
    engine.  I know yer' talking the O.S. .40 ABC versus a lapped-piston
    Fox .36 but yer' really talking apples and oranges here...kind'a like
    if I said my O.S. .61FSR ABC doesn't have near the power of my Chevy
    350 c.i.d.  What I'm saying is that, compared against a conventional
    ringed O.S. .40, the ABC version, IF it's properly broken in and
    running correctly, will be _noticeably_ more powerful.  The ol' Yeller'
    Peril was barely a marginal performer with a ringed .61FSR in it and
    switching to the .61ABC was like dropping a .90 in it...the difference
    was _that_ dramatic.
    
    Also, I'm not sure where yer' getting this idea that an ABC must be run
    richer than a ringed engine.  I run the .61 ABC in the ol' Yeller' Peril
    at absolute maximum peak at all times...I _have_ to due to the plane's
    elevated weight; otherwise performance would be P-poor to below!  And,
    it runs no hotter (or cooler) than the ringed .61FSR that preceded it
    in the same plane.  Onliest thang' I kin' think of is that yer' engine
    is not broken in yet...ABC's _do_ take longer to run in.
    
    I tend to agree that ABC's _are_ just a tad fussier to break in than
    their ringed counterparts (but not that different from lapped piston
    engines).  This is why I'll seldom recommend an ABC to a raw beginner;
    he's got enough other pressures on him  in the early going and needs an
    engine that breaks in quickly and runs reliably.  Later on, YOU BET, I
    recommend nothing else than ABC and will buy nothing else myself from
    now on (where a choice exists).
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

         <<< Note 264.14 by CLOSUS::TAVARES "Stay Low, Keep Moving" >>>

Sorry John if I offended you, it was most certainly not intended. As Al pointed 
out in -.1 ABC is more power/lb than ringed engines. I have perceived a general 
trend of 'anti ABC' through the conference. Your note just happened to be the 
one I bit at.

I would hate to see a newcomer put of an ABC purchase and felt some response 
was necessary.

> I think it does this because the plug only typically goes
> slightly bad (deep inside the element), and improving the fuel
> flow/mixture makes it run better for a short time.  But the
> bottom line is that the plug is sour and needs to be replaced.

Very good point but I suggest the plug going slightly bad is probably due to
the deterioration of the element surface; ie: the whitish color of the element
compared to the silver shiny element when new. 

John

    Re: .15,
    
    I meant to add that I find the ABC much more (not less) tolerant of a
    lean/hot run...that's what it's designed for, after all.  The aluminum/
    brass/chrome components expand under heat at differing rates such that
    the piston will not sieze to the cylinder liner but will maintain
    optimum compression through a VERY wide temp range, far superior to
    lapped or ringed engines in this characteristic.
    
    Also, I find plug useage to be in absolute parity with my ringed
    .60/.61's...no better, no worse.  As I said, the only thing I can think
    of with yer' personal situation is that the engine simply isn't broken
    in yet as these symptoms (hot runs/plug useage) can exist with _any_
    new engine.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

  Well I pulled the carb apart Saturday night and checked the tank..etc..etc..

  I found nothing.  When I got to the field on Sunday I adjusted the setting
and went up for the first flight.  The engine leaned out after about 8 minutes
and I had to make a quick landing.  The rest of the day (fun fly) only had 
flights of 3 mins or less, so I don't know if I got it richened enough now
or not.
  Oh yeah...I had been having a minor problem with the seal between the
Snuffler and the main part of the original muffler, so I sealed it up
with RTV.  That may change my tank pressure so I'm going to start from 
ground zero with the adjustments next time I get out.


             Jim

    I'm running into a problem with on OS .46 SF that I could use some help
    with.  When the engine was brand new, I did the usual 2-3 tank burn at
    a rich setting.  The first 10-15 flights were perfect from an engine
    standpoint, ie, no problems.  Then, one day, it started to stall out
    during touch-and-gos as I was giving it full throttle on the up swing. 
    No amount of playing with the needle valve or carb helped.  It kept
    stalling out during power up.  Then, on some successive flights, it
    just up and quit during normal flight.  On the ground, we had a devil
    of a time trying to get it to run at all.  Finally, we bypassed the
    in-line fuel filter and Dubro Quik-fill valve, and things seemed to
    improve.
    
    I then cleaned out the fuel tank, changed some tubing that had tiny
    holes in it, cleaned out the fill valve and filter, and tried another
    flight.  Same problem.  Nothing I've done seems to work.  My instructor
    says its a fuel flow problem and that the engine is not getting the
    right amount of fuel, hence starves and dies.  He thinks the Quik-fill
    is the culprit.  If its the fill valve, then it had to somehow go bad,
    because this engine had many flights on it before the current problem
    showed up.
    
    So, what am I dealing with?  Is it a fuel flow problem or a balky
    engine?  BTW, this is a ringed engine, if that makes any difference.
    
    Some input from the engine mavens out there would be appreciated.
    
    Thanks,
    

    I'm no engine guru, but you could read about my woes with my OS SF 46
    ABC in 239.2122, and see if you find any fresh ideas there, though your
    problem is a different from what I have described therein.
    
    Nonetheless, I must admit to having my engine quit on throttling up on
    occassion - especially after a long duration of idle (while coming in for a
    landing). I have adjusted my lowspeed needle for rapid/instantaneous
    response when I open up from idle. Most of the days, my engine
    throttles up fine, but on a _few_ occassions, it has quit at
    embarrassingly low altitudes, resulting twice in landings into pricker
    bushes.
    
    One instance that I distinctly remember is when I was in my marathon
    century touch-and-go session. The engine, which had been throttling up
    fine for over 90 T&Gs, began to hesitate the last few times, with the
    hesitation duration increasing with each T&G. Perhaps it was due to the
    sun going down and the consequent drop in ambient temperature - I had
    not re-adjusted the mixture. Engine was fine the next day.
    
    Btw, I too use a Du-Bro Kwik-filler, and a Sullivan crap-trap in line
    filter without having experienced any problems. Steve Smith owned a
    ringed version of the SF46 just like you do, and you might try tapping
    him for his experiences at RVAX::SMITH.
    
    I still do get into trouble occassionally when I try hovering my plane 
    for 3~4 minutes, with the engine idling all the while, but then, I am
    really asking for trouble with the engine loading up. Overall, my
    engine can change from a kittens purr to a lions ROAR  'most always.
    
    I would be interested to hear how you solve your problem ultimately,
    since I haven't been able to find an explanation for mine misbehaving
    on the few occassions that it did.
    
    Good Luck
    
    ajai
    

    Re: .-1, Joe,
    
    If bypassing the fill valve/fuel filter, i.e. running a line directly
    from the tank's clunk line to the carb, corrects or even improves the
    problem, you've definitely isolated the problem to either the fill
    valve, the fuel filter, the connecting fuel line or any combination of
    the three.
    
    The fact that the engine _used_ to run fine with these components is
    immaterial; things go bad and cause problems.  Again, the acid test is
    how the engine performs with these items shunted out of the circuit.
    
    Other things that can cause trouble are:  pin-hole leaks anywhere in
    _any_ of the fuel tubing, even inside the tank; pinched/doubled up
    clunk line; pinched/blocked overflow/vent line.  Fuel system problems
    are most often the culprit in these type situations but poorly adjusted
    carbs can also be at fault.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

    I acquired a used-but-in-good-running-condition K&B .40 with a Perry
    carb, and have been using it in my Eagle 2 lately.  Although the engine
    has been running pretty well, I have noticed raw fuel leaking out of
    the shaft (just behind the prop) at all speeds, but obviously much
    worse at full power.  As I hold the plane from the rear while adjusting
    the needle valve, I get sprayed by fuel.  I also have been experiencing
    difficulty getting the idle adjusted right lately.
    
    Question: what is the reason for the fuel leakage at the shaft?  Can it
    be fixed, and is this a do-it-yourself fix or a factory rebuild?  
    I tried to tear down the engine but could not separate the shaft from
    the housing even after removing the locking pin.  So I stopped there
    and decided to post this question.
    
    Any thoughts?
    
    Thanks,
    Joe
    

    Joe,
    	Many engines use this to lubricate the front bearing.  WHen it's
    excessive it may signal that the front bearing is wearing and may need
    to be changed.  Maybe someone else can shed some additional light?
    
    
    Tom

Don't worry about it. The crank case will be positive pressure and will tend to 
force fuel through the front bearings.

If your engine has just started loosing fuel through the front bearing it will 
be a worn seal on the bearing; that is the metal or rubber seal over the 
bearing.

If the engine has always done it you will find it probably does not have a 
seal. I remove the seals to ensure the bearings are cooled and well lubricated, 
many high performance engines never have a seal. The overall effect on 
crankcase pressure in not important.

A well lubricated cool bearing is more important than the lose of a small 
amount of fuel.

John

    Last night while flying my Skytiger powered by an OS 46 SF, I
    experienced a VERY wierd problem.  I had already put in several 5-7
    minute flights and had refuled for the next take-off.  While taxiing
    out of the pit area, I heard a loud POP, almost as loud as a
    firecracker, and the engine goes dead.  I looked at the engine, and in
    disbelief saw that the glow plug was missing.  It apparently just BLEW
    OUT!!?  Never found it.  The threads on the cylinder head were in
    pristine condition, so apparently, the glow plug kind of just
    disintegrated and blew away.  Has anyone ever heard of this before? 
    I'm baffled as to what may have happened.  I know the plug was tight,
    because I had checked it just prior to starting the engine.  I wonder
    if the heat might have something to do with it.
    
    Last night's temp at the Merrimack field I estimate to be in the 80-85
    degree range.  Not terribly hot when I consider that last Sat I flew in
    temperatures close to 100 degrees.  The engine has been rather balky in
    this temp range with more frequent dead stick landings, but other than
    that I can't figure what went wrong.
    
    Puzzled,
    Joe
    

    >> Has anyone ever heard of this before.......
    
    
    			YUP.....Seen it once.
    
    			Can't explain it.
    
    	Good thing you wern't leaning over the engine adjusting the needle
    when it blew.
    
    	"OS 46SF SHOOTS MAN DEAD......STORY AT 11."

    Re dead stick landings...
    
    MY 46 ABC is verrry fussy about being kept clean. If I let crud collect
    on the cooling fins, the engine overheats, and starts losing power, and
    eventually dies. May not matter with non-ABC though
    
    ajai

    Well, another strange thing happened to my OS 46 SF yesterday.  I
    reported that it recently blew out a glow plug.  Well yesterday, after
    a 10 minute flight, I brought it back to the pits for re-fueling.  As
    the plane sat there in front of me, I heard a metallic clanking sound
    and the rear end of the muffler just falls off and lands on the
    ground!!?  Upon close examination, what happened was that the head of
    the loonng screw that goes down the center of the muffler had parted
    company with the screw, and I guess there was enough tension in the
    shaft that as the head popped off, the stored energy in the shaft
    pushed the back end off where it harmlessly fell on the ground.
    
    I'm really glad this didn't happen while it was airborne for two
    reasons.  First, I would have to spend more money to buy the missing
    part whereas now I only have to buy the screw.  Second, I was curious
    if the engine would run without the whole muffler, so I attempted to
    start it.  Would not run at anything above fast idle.  I guess the
    needle valve and mixture settings are different with and without
    muffler.  Soooo...if it had fallen off at full throttle while I was
    doing some "death defying maneuvers" (that's an exaggeration, but who
    cares, I was in dangerous configurations more than once) I might have
    lost power and gone in.  Speculation, yes, but with my luck, its very
    possible.
    
    Now I'm getting paranoid about this most wonderfully touted engine. 
    Could there be something intrinsically wrong here?  Is it running too
    hot?  Is it in need of some kind of TLC I simply am not aware of?  I
    think I treat my equipment with the kind respect and care it deserves,
    but perhaps I am ignorant of something and not doing it all.  ANy of
    you engine mavins got any helpful tips?
    
    BTW, I think it looks pretty clean, Ajai, but as you mentioned in -.1
    this might not be as much of an issue since mine is the ringed version.
    
    Thanks,
    Joe...still puzzled and wondering what will go wrong next. 

    Well, it is time for me to clean my engine again this year!! It fooled
    me once, but it can't fool me all  the time :-)
    
    Gee, but if someone could get my OS SF 61 ABC pumper to run just fine,
    I could have some more fun with my WOT4 instead of doing all dead stick
    landings!
    
    ajai

    RE seperated muffler
    
    
    Not all that uncommon. That long screw has always been a problem. They
    usually wind up stripped due to people constantly re-tightening them
    and getting so fed up that they finally over tighten it and strip it.
    
    I just bought a replacement muffler for an OS45 FSR and it's still two
    piece, but instead of the screw, the back piece is threaded and screws
    directly into the front piece. I guess maybe OS had enough complaints.
    
    I've also seen the muffler's come appart in flight. Either the screw
    will come loose and the muffler will fall apart like yours did, or
    basically the same thing will happen with a Snuffler. One thing I can
    tell you is there is NO mistaking when part of your muffler comes off.
    The increase in DB is incredible. If it were to happen, you have to
    throttle back immediately and land. More often then not, the engine
    keeps running but with the loss of back pressure, probably not well.
    It could just as easily die. The only thing you can do is throttle back
    and make the best landing you can.
    
    Steve

    OK, different engine problem...
    
    I have a K&B .40 on one of my Eindeckers..  10x6 master airscrew at
    the moment..  I do have a heavy hub (but not the extra heavy).
    
    I originally had the standard carb on it, but since I had a perry
    carb laying around, I put that on..  There was no improvement to my 
    problem...
    
    The problem is that it is taking the engine a (comparatively) long time
    to wind down from high to low speed.  You see the barrel close from
    full open but the rpm's don't drop right off.  If the barrel is
    completely closed, it could take more than 5-10 seconds before the
    engine will get to low idle and a few more seconds before it stops.
    
    I find it hard to believe that he prop/heavy nut are providing that
    much "flywheeling", but that is what is really seems like.
    
    Any ideas of what else I could look for??
    
    thanks!
    jeff
    

    The initial thing to do would be to take the Higley nut off and ground
    test it to see if it is as simple as "flywheeling". It could be that
    you've got an air leak somewhere on the case/carb (not on a K&B 8^) and
    the air is allowing it to continue at speed untuil the necessarily rich
    mixture gets out of the crankcase. I speak from experience on this one
    (not a K&B) in that I had a backplate screw missing and the engine
    would only run very rich and would lean out in the air. I didn't notice
    much flywheeling but it did take somewhat longer to wind down.

    I had somewhat of the same problem with an Enya 60 and Perry carb.
    I'd close the throttle all the way and still had to put my finger
    over the carb to stop the engine. I found three things, all with
    the carb, and all air leaks. The first was with the O ring seal on
    the barb neck. I replaced it with a thicker one causing you to have
    to compress the carb into the crank case more before tightening giving
    a better seal. Second was the two screws on either side of the carb
    that hold it into the crank case. Even though they would tighten up,
    air still leaked around them. Put them in with either lock tight to
    seal up the threads or silicone. The third was the hardest and is
    something I can only attribute to a warped or "un-round" carb barrel.
    In making the adjust with the little screw that governs how far closed
    the barrel will go, you put a piece of tubing on the fuel nipple and
    blow through it while closing the carb. When the carb is really closed
    you should barely be able to blow air through the tube. I found that
    when the barrel was closed "to the eye", I could still blow a fair 
    amount of air through the tube. closer examination of the carb barrel
    revealed a depression/dent that was leaking air. I adjusted the screw
    so that the carb barrel went "way" closed which allowed it to get by
    the dent and "seal" properly.
    
    In other words, check the carb out REAL WELL.
    
    Steve

    I also believe that even though the engine might be running ok,
    an improperly adjusted low end mixture will cause the same symptoms
    you describe.

    Actually, I have two problems I am trying to fix....
    
    1 - OS .50 FSR (fuel system has a dubro quick fill - YUK!)
    
    Engine has good idle and good high end performance.  However, 
    adjustments to the needle valve do not seem to affect the engine!
    I can turn it out 2-3 turns without is getting richer.
    
    I think it is an air leak problem, but I can't find anything.  Maybe it
    is the bloody filler valve.  Any other suggestions??
    
    
    2 - OS .25 in my gremlin...  
    
    Overheating like crazy.  This engine has taken signifiant abuse, eating
    dirt and Jim's gremlin :-)  The bearings "feel" OK, although there is 
    quite a bit of forward/backwards play.
    
    What else should I look for when I break down the engine??
    
    (Guess I will have to use that shinny new .25 for the demo!!)
    
    Suggestions are welcome.
    
    Thanks!
    jeff
    

    I had an OS50 that was a little sensitive when I first bought it so I
    sealed it up by putting hi temp silicone in a bead around the carb base
    and by using teflon tape around the needle valve threads.  I also
    pulled the crank case back cover, gently removed the gasket and put a
    very light coat of silicon on the gasket, then with the silicon still
    wet I put it back together.  Gives you a nice rubberized seal that will
    survive inspections and cleaning.
    
    Be careful with the silicone because it can etch the crank if you let
    it get below the carb.
    
    For what its worth I always used an air filter and the motor never gave
    me trouble in two great seasons of flying.
    
    Good Luck.
    
    Will

    Well, I believe I got the OS .50 running better.  The problem is, I
    made 2 changes at once, so it is not clear which one solved the problem
    (although I believe I know...)
    
    1 - I removed the quick fill valve.
    2 - I went from medium to large diameter fuel tubing.
    
    I believe that the fuel tubing was restricting the fuel flow.  As a
    result, no matter how many turns rich I turned the needle, it didn't
    change the actual mixture.
    
    It is running like a charm now!
    
    (I haven't had a chance to tear down the OS .25 yet...)
    
    cheers,
    jeff
    

    Jeff, I had _bad_ results both times I used one of those Dubro Quick
    Fill valves.  They are a nice concept, but the performance is very
    poor.  I think they restrict the flow of fuel more than they should,
    and as a result, cause the engine to starve for fuel.
    
     I have two used QUick Fill valves for sale...real cheap.  Any Takers??
    
    Glad to hear your '50 is back in the running.
    
    Regards,
    Joe

    Does anyone know of the top of their head what bolt size is used to
    fasten the muffler to the engine on a Royal .45 snhurle (sp
    ?)
    
    Thanks
    Bruce