Stuck valve

[dads6x6]

I think my M37 has a stuck valve
I didn’t start if for the summer and now when I start it,
it misses. Have to throttle up to keep it running
fuel pump is recently rebuilt by Midwest military. I also rebuilt the carb last summer and it ran great after. how can o check and if so do 8 have to take the head off to fix it?

thanks

 

[Black Ops]

I would pull the valve covers off to check. I have freed up valves through the spark plug holes.

 

[dads6x6]

I will pull them see what I can find out

thanks

 

[dads6x6]

So then the next question is how did you get your M37s valves unstuck?
never had this problem.

 

[mdainsd]

Mine came out of long term storage after a depot rebuild (20+ years). It ran poorly when I got it started. Compression test showed two cylinders with 0 Psi.
I removed the head and yep, there they were, 2 exhaust valves stuck open. I tried to gently tap them down to get them moving, but no luck. I ended up taking off the manifolds, then I found some plastic caps that where a tight fit in the exhaust ports. Next I filled the exhaust ports with MMO. Each day I would come out and try the very gentle tap. Nothing. It took two solid weeks for the MMO to soak in enough that I could get the valves to move, but they still stayed stuck open. Since they were now moving I removed the retainers and took these two valves out. Cleaned them and the valve guides with MEK, lubed them and reassembled. Perfect! Runs like a top and never had any further issues. I also treated the motor to doses of MMO in the gasoline and in the oil.