Hi dose anyone know the ballpark compression a Yamaha 50hp 2 stroke should produce? I think it's a 1985 engine.
I need to re do the test because I didn't have the throttle wide open. But I can't find any figures regarding what it should be. All the readings were the same and I've noted them down but left my note book in the workshop! The engines running well I just thought I'd test it for piece of mind and I got a compression tester for Christmas so had to use it!
As long as all the readings are the same you're ok. Compression testers aren't usually very accurate in PSI-it's just the needle position being the same that counts.
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Hi dose anyone know the ballpark compression a Yamaha 50hp 2 stroke should produce? I think it's a 1985 engine.
I need to re do the test because I didn't have the throttle wide open. But I can't find any figures regarding what it should be. All the readings were the same and I've noted them down but left my note book in the workshop! The engines running well I just thought I'd test it for piece of mind and I got a compression tester for Christmas so had to use it!
Cheers
Ross
Anything over 100 P.S.I and it's OK. 130 P.S.I would be good for that year.
Think about what the piston is doing. Compressing a static volume of air by a given ratio = 100 psi "compression".
Idle does this about 800x a minute. WOT about 5500. Its still just a static volume by a given ratio. You will get more blow-by when the rings are cold. But you wouldn't run a cold engine WOT anyway.
White Noise
