compression readings

Indiana George · Dec 20, 2009

I took compression readings on my farmall c today.#1=88psi,#2=100psi #3=86psi and #4was 92 psi.Are this readings ok?Back in the fall i had a hard time starting it.
Thanks George

Andrew Z · Dec 20, 2009

those numbers are good, stock compression is right around 100-110 psi. More important is that all your readings are right around each other and not one real high or one real low. i think you have other issues then the compression for not wanting to start. carb, dist/mag etc.

Andrew

rustred · Dec 20, 2009

kind of a rule of thumb would be 10 percent difference, so yours are in the ball park.

CNKS · Dec 20, 2009

Borderline, technically none should be below 90. Those readings have nothing to do with hard starting.

Janicholson · Dec 21, 2009

I would ad that the readings could be low for three reasons (but they are not very low)
1 The throttle could have been closed causing some vacuum on the intake side when doing the check, must be wide open.
2 The rotation speed of the starter could be low causing low test pressure (must crank fast)
3 The accuracy of all gauges need to be checked once in a while!
It is not the issue with starting though. Weak spark, or fuel mix, or vacuum leak, or fouled plugs will do that! JimN

compression readings

Indiana George

Member

Andrew Z

Well-known Member

rustred

Well-known Member

CNKS

Well-known Member

Janicholson

Well-known Member

Similar threads