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Outboard sounds like its misfiring

A

auchandler1

Contributing Member
Just recently bought a new boat and has a 1989 Force 125 outboard on it. The boat ran well going up to 35-37 mph. Put a lower unit in and went out on the water ... now I hear the motor misfires when I get up to a certain speed with the throttle going down and I only get up to 13-18 mph. Not sure if this is electrical or gas problems but need help ASAP!
 
I check the piston on cylinder 4 . It is flush at the end and looks black and the others look 85 % black and is not flush at the end. Is this causing my boat not to work properly. Do all pistons need to be replaced and lubricated ?
 
No usually no compression is a fix one cylinder.
It could be the head gasket or the rings.
Remove the head and look for damage in the bad cylinder.
Check the gasket for any bad spots.
Profile?? You might be close to somone who can help.
Pics??? J
 
Cylinder looks like it's blown. Cylinder has a gap on the side like it was melted while 1 and 3 looks fine but 2 looks like its starting to melt on the side. I have talked to a few captains who know motors well and they said if a cylinder has 0 psi then its blown.
 
I am very interested in rebuilding myself. Im sure it is a lot cheaper to do. I would like your thoughts on this. I have a repair manual and am very motivated to do it.

Anyones opinion would help.

Thanks
 
The most important thing is a GOOD machine shop.Then a FACTORY manual is a good thing to have too.Getting the holes bored right is the most important thing.
Figuring out why it went bad is important too.If not it's gonna happen again.
Are the carbs set wrong? The fuel recirc system clogged and air leaks? Etc.
It's not that hard to rebuild.Just take pics along the way.
Make sure the connecting rods ends don't get mixed up.J
 
Post some pics.No re-sleve on these heads.Re-bore to.010 if possible.
Take it to a machine shop and they will tell you what you need.Without seeing it we are only guessing.
 
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