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Compression Test

You would want to see 120 +-----Very important that they be the same within a few PSI.------Modern computer manufacturing ensures parts are the same when engine is assembled.----What issues are you having with your motor ?
 
racerone said:
You would want to see 120 +-----Very important that they be the same within a few PSI.------Modern computer manufacturing ensures parts are the same when engine is assembled.----What issues are you having with your motor ?
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thanks for getting back to me . I am looking at this boat to buy are you sure it has to be 120 + because i did the test and it is 90 all around.
Thanks, John
 
Are you sure your gauge is good and calibrated to read properly ?---Model # is.----Compression test results usually brings on a variety of opinions.
 
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I had an issue when checking the compression on my 1988 Johnson 90 hp.
One cylinder read 120 lbs, then when I checked the next cylinder, it was only 60...and I thought "What the hell?"
Went back to the first cylinder...and it was 60!
After fiddling around with schrader valves trying to see if that was the problem - in the end, it turned out to be the hose.
Was dry rotting from the inside out, and that last blast of compression had punched a tiny hole in it.
Replaced the hose with a section of fuel line hose I had kicking around...and all 4 cylinders read 120 PSI.
So if your gauge is pushing 30 years old like mine is, you might want to check the hose....lol

CarMech1969
 
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