1980 evinrude 35hp compression

[MassBassin]

Hey guys, I did a compression test on my motor today. Is it normal to take 10 seconds to reach max reading? Also should it hold that number on the gauge once you stop cranking? When I stopped cranking the numbers slowly dropped.I got 120 in both cylinders is this close to factory specs? Thanks!

Jason

 

[junior1113]

Re: 1980 evinrude 35hp compression

it should'nt take 10 seconds maybee 3. and it should hold pressure for a while. id make sure guages are'nt leaking. if guages are good engine is going bad. do they both leak out like that? sounds like a scored piston(s)and or sleeves

 

[MassBassin]

Re: 1980 evinrude 35hp compression

yeah they both leak out like that.

 

[tashasdaddy]

Re: 1980 evinrude 35hp compression

get another guage, it should not leak down, it is a guage problem. follow the steps here.

there are no published factory specs, as compression guages and techniques of testing are not constant. the numbers look OK, but i would retest. you want both numbers to be within 10 % of each other.

 

[MassBassin]

Re: 1980 evinrude 35hp compression

ok will do. Thanks for your help!