4.5 merc piston slap

[Joe_G]

piston started slapping around a bit
after this weekends full throttle
30 mile boat ride, but it only rattles
when your going slow, no rattles
when your going fast, if you can call
10 mph fast. Question is, is this a do
it yourselfer? Do they have a cylinder
that will come off like a dirt bike does?
I'd hate to spend $30 for a manual only
to realize that I can't handle the job.
Any advice would be appreciated..thanks...Joe

[tubejig]

Joe_G, a couple questions for you. What kind of
motor is it? How old?

Just so you know, I rebuilt my Evinrude 40 this spring.
piston-$82
gasket kit-$95
rings-$30 a set x 2
thermostat-$12
bearings-$29 a set x 2


tubejig

[Joe_G]

It's a 1980 mercury 4.5 horsepower, single cylinder,
with a blue stripe around the engine cover.
Called Mercury Marine today (sure wish they had an 800 #)
and explained the problem. They asked what octane fuel,
and I said 93, and they said WRONG! Too much heat for
such a small engine. This is the first time I've ever used
93 octane. Mercury suggests 87 octane, change the plug,
& hopefully I didn't blow the upper end. So I'll try it,
but after 5 gallons burned, I think I did some damage.
What do you think TJ?.........Assuming I need a new piston, rings
& wrist pin, is she doable?........Thanks......Joe

[tubejig]

Joe_G, Its a very simple repair since you don't have
the electrical parts to deal with as with the electric
start motors. Before you make the repair, price the
rings, bearings, piston, and gasket set. This way you don't tear the motor down and get a big surprise.
Do not use any type of liquid gasket, always replace with the factory recommended parts or you could be back to square one. Figure on 2 weeks to get the parts after you order them but
don't be surprised if it takes longer. If you have any
other questions let me know. One last thing, if you
don't have a history of being mecahnically inclined
don't do the job, leave it for the professionals. Most
marine repair shops will charge more to put back
together what someone else has taken a part.

tubejig

[Joe_G]

Thanks for the reply TubeJig. I think I'm
mechanically inclined enough to do it.
Do believe I'll need the shop manual tho.
I've done the same thing on an aircooled
YZ250 & a liquid cooled arctic cat ZR500.......
It's just that when you pull the engine cover
off an outboard.....well.....looks funny.
Thanks again & take care.....Joe