aprox. how much compression should i have. 9.9 82 johnson

[Dan Pike]

I checked my compresion on both cyl, after 3 pulls on the top cyl. it was at 100, after 3 on the bottom it was at 75 but did not drop, im guessing this difference is due to how hard you actually pull, but does anyone know about how high it should be.

 

[Xcusme]

Re: aprox. how much compression should i have. 9.9 82 johnson

It's really not important how fast you pull rope for a compression test. Just pull like you're trying to start the motor. Compression readings should be the same or within 10% of each other. Due the age of your motor, readings in the 90 and above would be good. Use a screw-in type guage. Different guages give different results. Pull the head gasket and have a peek at the cylinder walls. Perhaps you have stuck rings, a decarb could help, but don't expect miracles. Pulling the exhaust cover you can see the rings. Using a soft stick, see if they move freely within their lands.