1984 35 HP Mercury Compression Ratio?

[bc98usa]

Does anyone know what the compression ratio for an '84 35 HP Mercury outboard should be? I have a compression tester but I'm in the Northeast and the weather has been too nasty to check it until it warms up. The motor was supposedly winterized as well. What would one do to winterize this type of motor?

 

[JB]

Re: 1984 35 HP Mercury Compression Ratio?

Howdy, bc98usa.

Welcome to iboats.

Compression ratio is pretty irrelevant in 2 strokes. What you are interested in is compression pressure, in pounds per square inch (psi), matching in the cylinders.

Because of differences in guages and technique the actual numbers don't matter much as long as they are in the vicinity of 100psi or above. What matters most is how closely the cylinders match each other. 15% is about the maximum allowable difference, and under 10% is considered good.

 

[bc98usa]

Re: 1984 35 HP Mercury Compression Ratio?

Thank you very much for your quick reply. Your forum is great!