1GM10 no compression after sitting for a couple of years

[heron237]

I'm suspecting stuck valve, any thoughts?

[SailingHarmonie]

Assuming it ran when it was put to bed, and If there is NO compression, that's about the only answer...

[deblen]

Remove valve cover. Stuck valve will be stuck open, if no compression.
Spray some WD40.-wait.
Using a piece of wood against rocker arm,tap wood gently to drive rocker & valve downward slightly. Re-spray-repeat.
If lucky,valve will come free & "bounce" when tapped.
Do not roll the engine until valve is fully free.
If this doesn't work,remove cyl head.
Cheers/Len
http://j30.us/files/YanmarGM&HMWorkshopManual.pdf

https://www.youtube.com/watch?v=FCfBCufQLis

[skipperpete]

Originally Posted by heron237

I'm suspecting stuck valve, any thoughts?

Any chance the decompressor is active?

[heron237]

The compression lever is not engaged, I just lifted the valve cover and sprayed WD-40 on the valve side, the rockers and push rods go from loose to tight as I hand turned the engine. Just soaked the valves and springs, let's see ...I don't have enough clearance to fully remove the valve cover,

[GrowleyMonster]

Originally Posted by heron237

I'm suspecting stuck valve, any thoughts?

That's the first thing that popped into my head when I saw the title of the thread. Second thing is decompression lever or device. My money is on stuck valve, and now you know how to proceed. Fairly low risk operation. WD is your friend. A few taps ought to get it free.

[deblen]

https://sbo.sailboatowners.com/downl...-L_3HM-F-L.pdf

[heron237]

WD-40 is not my friend, but PB Blaster is, sprayed on, including up the mixing elbow, waited an hour, and voila, runs like a champ.