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1987 70 hp johnson

S

Silvano silva

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"what is the normal compressio

"what is the normal compression on this motor? my motor was checked and has on cyl#1 115,cyl#2 100 and cyl#3 95psi."
 
"Usually the compression is ar

"Usually the compression is around 125 psi if memory serves me correctly.

Your readings indicate that the engine has been run for some time with fouled carburetors, resulting in a lean running engine.

The different in those readings (low to high) amounts to 20 psi.... not good!"
 
"what needs to be done to corr

"what needs to be done to correct it, a tune up, overhaul?"
 
"Usually a compression differe

"Usually a compression difference such as that points to a overhaul scenario.

However, perhaps it is something as simple as a head gasket failing. I'd suggest that you remove the cylinder head to inspect the head gasket, block and cylinder head sealing surfaces, pistons, and cylinder walls first. What you find there should point you in the proper direction.

Keep us informed."
 
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