Yamaha 250 compression

[Knot Working]

Hi guys, I just bought a '95 Yamaha 250 from a friend. I have known the guy for a while and also know that the motor has been sitting in his garage for almost 2 yrs. I checked the compression and it was an even 100 psi on all cylinders. I installed it on my boat and it runs like a dream, however, I have since read that compression should be in the 125 range. Is my motor doomed? What should I do? Thanks,<br /><br />M-

 

[Capt Ken]

Re: Yamaha 250 compression

Yes, you are correct, the engine is almost dead. Tell ya what I'll do, I'll give ya $100 cash and come pick it up from ya. Its the only friendly thing to do. Naw, all kidding aside, the compression is fine. Compression can be affected by slow cranking speed or your guage may be incorrect. Anyway, the cylinders are even and it runs good. Don't worry Be happy, have fun and enjoy. Worry about something more serious like how you're gonna buy fuel for that beast.

 

[Knot Working]

Re: Yamaha 250 compression

Thanks Ken, Can the fact that is has been sitting for a couple years have any adverse effects? I put some gas treatment in but thats really all I know to do. Thanks,<br /><br />M-

 

[Capt Ken]

Re: Yamaha 250 compression

I might throw some two stroke oil in the fuel just to be sure everything gets lubed good but if the engine has been stored inside and in a dry enviroment, not to worry.