Low cylinder compression

[Eddyhifi]

Hi,i have a 2 stroke Yamaha 130hp 1998. The engine used to work good and 135 psi in the 4 cylinders.After two months with not use, now i have the engine failing and lack of power.I took the compression again and now there is one of them with only 25psi????? It could be rings stuck? Thank's in advanced for any help.

 

[JB]

Re: Low cylinder compression

Hi, Eddy.

Welcome to iboats.

It could be that or it could be a blown head gasket. You can try a decarb treatment to loosen any carbon sticking. If that doesn't work you probably need to pull the head and inspect.

 

[Capt Ken]

Re: Low cylinder compression

Carboned rings are not going to drop the compression like that without dropping compression somewhat in the other cylinders. Go ahead and pull the cylinder head and you will probably see a burnt piston from a lean fuel mixture. It's rare for a Yamaha to blow a head gasket even if overheated.

 

[Eddyhifi]

Re: Low cylinder compression

Carboned rings are not going to drop the compression like that without dropping compression somewhat in the other cylinders. Go ahead and pull the cylinder head and you will probably see a burnt piston from a lean fuel mixture. It's rare for a Yamaha to blow a head gasket even if overheated.

Thank's a lot. Do you think probably i have a broken ring and damage the piston? i have to check it out.