Farmall H valve stuck open

I bought a farmall H really cheap. Metal is straight and in good shape. It was running and transmission and all seemed fine. I was thinking it sounded sort of like a johnny popper and smoked just a tiny bit of oil. Well It's basically running on two cylinders after an inspection. First thing I did was checked the plugs which needed replaced. The 2nd cylinder problem was the plug wire needed replaced. The 1st cylinder after pulling the valve cover I noticed the exhaust valve is stuck open. So much so that the rocker arm is off of the push rod. What is the most likely cause of this? I know this tractor was sitting for quiet a while before the guy I got it from got it running. Is it just stuck from sitting? I was thinking of pulling the head and spraying some pb blaster down the valve guide and using a mallet to pound the valve back in and hoping it doesn't stick when I put it back on. Or do I need a valve job after this? Also is there any chance of a bent valve on these engines if stuck open or is there plenty of clearance? Thanks

probably stuck from condensation, at least the valve guides must be in good shape or the valves would not get stuck. yes when stuck open the pushrod will fall out when engine is turned over.i have been sucessful in using a long screw driver through plug hole to push them back up with lubrication. just keep lubing and tapping on valve lightly and working up and down and it should free up. valve will not visit piston just from being stuck. no need to pull head either unless all else fails. if you get valves free then work it for a bit and check compression then you will know what you have for engine condition.

Ok I'll give that a try. There was condensation on the inside of the valve cover. The inside of the valve cover was milky white but no signs of water in the oil anywhere else, or oil in the water for that matter. I guess some water got in there while sitting and there is still a little that is turning to steam when the engine gets hot and going to the top of the engine.

Most likely the exhaust valve is stuck open from sitting. I ran into similar situations with both a Super H and a 300 that sat unstarted for several years. This fix worked for me:

First spray the stuck valve(s) with PB Blaster or similar. Now to remove the rocker shaft/rocker assembly to get at the stuck valve's stem. Gently hit the end of the valve with a brass hammer, a steel hammer with a brass drift, etc. Unless the valve is stuck really hard, once the valve is driven in 1/8" so it will suddenly spring free and return to the closed position. Repeat the spraying lubing and tapping until the valve closes easily with spring pressure.

If above doesn't do it, remove the spring keeper, cup and valve spring from the stuck valve. Then apply GENTLE heat (low propane torch flame) to valve stem near the guide. Tap the stem a few times with your hammer then spray the stem with PB to cool/lube it. Finally repeat the the tapping exercise above.

Once the valve works freely, check all the pushrods to make sure none are bent - any bent push rods must be straightened or replaced. Then replace the rocker arm assembly making sure all 8 push rods are engaged with their rockers. Finally check/adjust the valve clearances.

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There's plenty of clearance inside the cylinder for the valve. There's no danger of bending a valve as long as you don't get too enthusiastic hammering on it.

Remove the spark plug. Get a length of hard plastic rope. Ensure the piston is well down the bore. Feed the rope into the spark plug hole until the bore wont take any more. Spray some lubricant around valve stem. Gently tap the stuck valve stem Use the handle and turn the engine. The rope should compress and push the valve open. You may have to do it a couple of times before its completely free. Make sure you have plenty of rope still outside the hole?????????? Mike

I have an H that did that and I did what rustred said to do. Had to do it a couple times after running it for a while but now is fine. Did not have to remove the head, thank goodness. Allan.

Sorry that should say "the rope will compress and push the valve shut. It works on Cessna's Mike

I had an H and it would only reun 3 cylinders and one valve spring was broken. Remove the valve cover and you can check for that.