2002 25hp low compression & won't start

[KennyCannon]

Hey everyone. First let me say that I'm completely clueless about engines. I bought a used boat a few weeks back with a 2002 25HP on it. When I went to look at the boat the engine started right up. I bought it, took it home and it started again. I started it a few days later and there was no problem at all. All this was done with muffs on and the hose running. Everything seemed perfect. Then I went to put it in the water and it started for a few seconds and stalled out. It hasn't started since. I called a mechanic and he rebuilt the carb and put a new pull cord on. When he returned tonight to put it all back together it still wouldn't start. After hours of not knowing what was going on, the mechanic did a compression check and it was 60 PSI in both cylinders. He basically said that there was nothing he could do (this was after paying him $500 for the carb rebuild and the pull cord assembly thing). After he left I did my own test and it was between 60 and 62 in both cylinders.

BTW it's a 2 stroke and the oil/gas mixture was fine.

I know that 60 PSI is low but the fact that they are both basically the same is a good sign (I think). If anyone has any suggestions as to what I could try I'd really appreciate it. Thanks.

 

[Faztbullet]

Try another guage first and if still low pull the exhaust civer and inspect pistons/cylinder walls

 

[KennyCannon]

Thanks Fazt. What would I look for on the pistons and cylinder walls?

 

[flyingscott]

You will also need to pull the 4 access panels off of the intake side. You are looking for any score marks and damage to the pistons. 60 psi is to low even if they are the same A healthy one should have 120 psi.. You have a mercosil block they can be bored out if you get lucky and the bore is not damaged to badly.