85' Merc 20hp outboard tiller - what compression?

[311Hemi]

Had a bare of a time last year with this engine.....thinking I should check the compression on it to see if something is up internally. Anybody know what compression should be on this engine?

We have rebuilt/cleaned the carb...just can't keep it idleing. Has new gas lines (tank and engine side), o-ring on fuel bowl and new filter...no water in the fuel. Spark plugs are new. Adjusted the fuel screw and all as usual. It is also using a lot of gas from what I remember. Not sure if it could be something in the ignition....

Never had that much trouble in the past and have always been able to get her running good up until last year.

Need to get it running properly before opener!!

[311Hemi]

Anyone?

[marine_man]

I don't know what it should be.. but all your cylinders should be within 15% of each other... that'll help you narrow it down between the cylinders - higher compression = better

marine_man

[Valv]

Marine Man is correct, be sure it's almost even all the cylinders, I would say if it's above 100lbs it should be fine.