Compression issue on one Cylinder only

[fburke]

1985 OMC 3.0

Motor had spark but wouldn?t start so I did a compression check and found

Cylinder 1, 118 PSI
Cylinder 3, 115PSI
Cylinder 4, 115 PSI

These seem to be within spec from what I have read here.. any input from the experts?....?

BUT Cylinder 2 ?0 psi :facepalm:..?not even a blip on the needle?so I removed the valve cover ?I noticed that all the push rods were moving up and down as expected so I believe my Cam is good?if it was a head gasket I think would expect to see low pressure on 2 cylinders but not 0 psi on one of them??I noticed one of the lifters on cylinder 2 is stuck down?and l believe is the valve open that would explain the no compression issue.

So my question is, is there a trick to unstick this valve? I guess the worst case is the valve is bent and I have to pull the head and replace the valve?.and may as well do the seals ect on the others while I have it off.

I?m not a motor expert and am learning as I go so please be gentile with me?.lol

thanks guys!

 

[Bondo]

Re: Compression issue on one Cylinder only

1985 OMC 3.0

Motor had spark but wouldn’t start so I did a compression check and found

Cylinder 1, 118 PSI
Cylinder 3, 115PSI
Cylinder 4, 115 PSI

These seem to be within spec from what I have read here.. any input from the experts?....…

BUT Cylinder 2 …0 psi :facepalm:..…not even a blip on the needle…so I removed the valve cover …I noticed that all the push rods were moving up and down as expected so I believe my Cam is good…if it was a head gasket I think would expect to see low pressure on 2 cylinders but not 0 psi on one of them……I noticed one of the lifters on cylinder 2 is stuck down…and l believe is the valve open that would explain the no compression issue.

So my question is, is there a trick to unstick this valve? I guess the worst case is the valve is bent and I have to pull the head and replace the valve….and may as well do the seals ect on the others while I have it off.

I’m not a motor expert and am learning as I go so please be gentile with me….lol

thanks guys!

Ayuh,.... Pull the head, 'n see what you've got to work with,...

I wouldn't spend much, unless it's for a Full Over-haul,...

Those numbers say it's a rebuildable core motor,.... not a runner...