Conference vicki::boats

When I replaced the points on my Evinrude I installed the flywheel
"dry".  I have no idea whether this is the factory recommendation.

Shortly afterward the motor broke a flywheel key when it ran out
of gas and kicked back as it stalled.  I installed a second new key,
which also then broke within an hour of replacing it.  On the advice 
of a friend I checked the keyway for burrs and nicks, sure enough it
was slightly damaged (almost microscopic).  I filed and polished with 
emery cloth both the flywheel and the crankshaft, reassembled it dry,
cranked the heck out of the flywheel nut, and never had another problem.

Whichever method you use, use a new key and make sure the surfaces
of the crank and flywheel are immaculate.  Any tiny imperfection 
can stress the soft metal key, causing it to break at the most
inconvenient time.

Rick W.

    Hi,guys.
    
    I have a little to add. 
    
    Having been through this costly ordeal myself many years ago, I'd
    like to add a little nit to the "key" topic.
    
    The key serves no useful purpose other than to help align the shaft
    and flywheel at assembly time. No key is meant to bear any lateral
    load. If it were meant to bear loads, it would be probably called
    a "shear pin"!
    
    Read the &*&^%& manual, and apply the correct torque *honestly--no
    skimping!* or else you will probably not be as lucky as Mister Wilson,
    and wind up with a FUBAR crankshaft, caused by a spinning flywheel
    at high speed and a stalled engine at no speed. My price was a short
    block (can you say "big bucks"? I thought you could!). 
    
    I don't believe the manual calls for any greasing, but a thin coat
    of your favorite *thinnest* grease (marvel oil!) can't hurt. Just
    don't use any extreme pressure lubricants in there; it could interfere
    with attaining the correct fit on the taper. After a warm-up cycle,
    the grease could thin sufficiently to reduce the pressure in the
    fit.
    
    I use a thin coat of Dow-Corning's 4-compound which is silicon based
    when I want to make sure something doesn't rust. It can lubricate
    down to a microscopic film, and seems compatible with almost
    everything. It even has a pleasant taste!
    Nahh, just kidding on the flavor. Don't try it, you may like it!
    
    Mike

    Ok since you asked?
    I use "Never-Sieze" compound whenever I am putting a taper shaft on.
    Exception is prop's on shafts. I then use a very heavy molybdium
    disulfide grease, the prop will force itself plenty tight under load
    and it is real nice to be able to take off the prop when needed.
    
    Yea. I'll second the Marvel Mystery oil! What is that stuff made out of
    anyway?
    
                                                Walt
    

re                <<< Note 504.3 by PACKER::GIBSON "I'm the NRA" >>>
    
>    Yea. I'll second the Marvel Mystery oil! What is that stuff made out of
>    anyway?
    
>                                                Walt
    

	Awwww, maybe this belongs in the rumor topic, but I'd guess 
that ATF, power steering fluid, marvel mystery oil and RedeX are all 
the same base (-:

	R

	{BTW, a quart of ATF in 50 gallons of diesel fuel will  
*_REALLY_*  clean out the injectors.}

    
    
    I strongly disagree with all those who say to use some kindf of
    lubricant or anti- corrosive compund on a taper shaft.
    
     As someone said in one of these notes - READ THE MANUAL. THe friction
    between the flywheel  and shaft is what keeps everything in place- the
    key -s just an alignment device. Proper torque is also a must- too
    much= strippped or brken shaft, too little= sheared key.
    
     Some manuals even recommend that after shearing a key- to file all the
    nicks- put some valve grinding compund on the taper and lap the
    flywhell and shaft ( like the ground glass lids on some jars) to ensure
    a good metal to metal seat. Wih this kind of tight fit- yopu shouldn't
    get rust  because water simply can get in.
    
     Follow the manufacturer's recommendations- merc,OMC,FORCE all say dry-
    and specificallystate- do not use oil or a lubricant. 
    
     I saw a great example of this this past weekend- my neighbor changed
    points in his 40 HP Johnson. he didn't torque the flywheel and he
    sheared a key after about 45 sec of running. He sanded /filed the nicks
    put some anti size on the shaft- put in a new key, cranked down the
    flywheel nut real hard and got about 15 sec running time. He was
    adamant about the lubrication. AFter about 4hrs of this- he asked for
    help. By this time he had cranked the Flywheel nut down so hard he
    stripped it and boggered up the threads on the shaft. He was about
    ready to try a hardnend steel key ( another no- no!)
    
    I sent him down to the dealer again- 
    . get a new key
    .get a new nut
    . get the torque specs.
    
    I chased the shaft threads with a die, cleaned the shaft and flywheel 
    with naptha, and put a small dab of valve gringing compound on the
    shaft ( after filing the nicks around the keywy) . I spun the flywheel 
    around a few times and checked it. The pattern from lappiong
    indicatided that less than half the surface contact was in effect- the
    shaft/flywheel was showing the effects of the spinning wghan the key
    broke.
    
     I lapped until I got about 90% contact ( just a few minutes), cleanerd
    everything up again, put in a new key, torqued it down to specs and
    voila!- itran.
     
    Too often we read the manual last- The only time I don't is whern I'm
    stuck and have to get home.
     
     BTW this same chartacter used to have a 35 HP on this boat-he
    was running WOT one day and the threaded aprt of the crank snapped off-
    tha  flywheel came out of the back of the engine and made like a
    frisebee befrore shkippiong merrily across the bay. He had just
    chanfged points- had trouble with the keys shearing so as he said, he
    "torqued it down real good!"
    
     That flywheel on that old 35 must have weighed about 30 lb and it had 
    a nice set of teeth on the ring gear- he's lucky it didn't come out
    the front of the engine!
    
    
    

  For anyone who didn't (couldn't) read between the lines in the last couple
replies:

	The alignment key on a outboard (or Briggs & Stratton) engine is
	intentionally SOFT to allow a shear in the event the business end
	(prop/blade) stops suddenly so that you minimize the chances of
	twisting your crankshaft.   It's bad enough to have to replace your
	lower unit without the added expense of a powerhead as well.
	Don't ever put a HARD key in that keyslot or you're asking
	for big $$$ trouble..

Al