Two rear cylinders not Working?

[cruzoropeza]

87-90psi If I remember correctly and I removed the carb and there was fuel in the bowls, the last thing I need to check on the week end is manifold for leaks

[westernair]

87 to 90? Did the pressure stay the same or how much did it drop over 60 seconds?
I would also do the test just as is and also with a squirt of oil into the cylinders.
What was the compression of the other two cyclinders. I may be wrong but I would think they should all be over 140

[cruzoropeza]

I also thought it should of been over 120psi but I compared it two the two "good" cylinders, the ones that are working I'm getting 82-87psi and the "bad" ones I got 89-94 it held is for over 60seconds. I'll try the "squirting oil" and test it again thanks guys!!!

[Jim LaGuardia]

If you don't have at least 120PSI after 5 revolutions in each cyl, you must check the valve lash before continuing(.2mm) then compression test again. If compression is still low be prepared to spend some money for a top end.

[Stekay]

Jim,
I'm assuming the 120 PSI is with a warm engine and wide open throttle, correct?

[Jim LaGuardia]

Temp is not important, throttle plates always stay closed when doing a compression test, just crank engine for 5 revolutions and read results.
With the numbers posted, I would suspect the cam lost a bore plug and the pistons may have been damaged from the loss of lube.

[cruzoropeza]

I'm a very happy man!!!!!!! It turns out it was the manifold gasket, cut my self a couple of new ones and she running better than ever. Thank you all for your helpful tips! AMAZING!

[Pinzgauer Pete]

Bows...you're welcome!

[cruzoropeza]