Overheated my Merc 115, flywheel not turning fully

french-ian

Recruit
Joined
Nov 11, 2007
Messages
2
hi people

I have the misfortune of being very stupid - whilst winterising my 2 stroke 10 year mercury 115, I overheated her and the engine stopped - doh!

As it happens, the motor had a full 2000 euro service 6 months ago and was running fine so I'm hoping its recoverable.

I took off the flywheel cover and tried to move the flywheel - it only moved 1/5 circle, so I took out the plugs and filled the holes with the french equivalent of WD-40.

Two days later, now the flywheel moves 4/5ths of a circle, so I have the feeling its better, but the last 1/5th turn isn't budging. Looking at the pistons going in nd out (with aid of a chop stick), the 4/5 turn is enough to move all four pistons in and out, so I'm guessing there's another problem other than a stuck piston. Does any one have any ideas?

grateful for any suggestions...
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: Overheated my Merc 115, flywheel not turning fully

It's not common to have a bearing failure from a engine overheat but it is possible, I would lean towards a piston depoisting aluminum on a cyl wall from the overheat
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Re: Overheated my Merc 115, flywheel not turning fully

First check is with a flashlight down the plug holes (and look at the plugs) looking for alum shavings/flecks/pieces....anything alum. Find any, overhaul time. If ok:

Secondly, remove the exhaust manifold covers so that you can see the sides of the pistons and rings through the exhaust ports. If you can rotate the crank, do so while looking. Any signs of loose alum or gouging (pieces of alum stuck to ring) and you are dead meat. BTDT on a 3 cyl OMC. Took a .030 overbore overhaul to get it back in shape. It's ok to have some lines along the sides of the piston where the skirt slid up and down the sides of the cylinders, but no alum particles.

Mark
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: Overheated my Merc 115, flywheel not turning fully

I'm afraid you're looking at a complete teardown and rebuild. It got hot enough to begin to melt the pistons. Pistons are probably shot, cylinder walls maybe bad, maybe ok with acid wash. Bearings need to be checked, seals and gaskets are fried in all probability.

Sorry
John
 

french-ian

Recruit
Joined
Nov 11, 2007
Messages
2
Re: Overheated my Merc 115, flywheel not turning fully

Thanks guys, it looks bad but at least you've given me direction.
Alum particle check and then prob full strip down it is then...
should be a fun learning process at least!

just on the offchance, are any of you guys in southern france?
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Re: Overheated my Merc 115, flywheel not turning fully

No, but my wife's ancestors came from there.

Welcome to iboats. Hope you enjoy the experience. I do.

Mark
 
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