McCormick W4 won't run

[MIKE R]

Loss of vacuum could be valves not seating properly, stuck rings or bad gasket around intake manifold. I would do a compression test to give a little more insight into the problem. With stuck rings you can put some Automatic Trans fluid in to free the rings. I am thinking its stuck rings.

[DanB53]

I've got 0psi in #4. Judging by the posts you sent me to, it is a valve. But shouldn't it run on 3 cylinders still?

[MIKE R]

Shouldn't it run on 3 cylinders still?

You could still have a manifold leak internally from the intake to exhaust system at the heat chamber, or a external at the manifold where it meets the block. It shouldn't be a manifold to carb leak because of the new gasket in there.

[DJ54]

Sounds like #4 exhaust hanging open. That would explain the bang, when it runs out of gas. Hopefully the push rod just dropped out of the rocker arm when the valve stuck, and did not bend the push rod. Seems one of the other three should at least give a little poof, if getting fuel, and valves half way decent.

Had this tractor been sitting a while..?? From the looks of the picture in your avitar, looks like it was just painted/restored..?? Was it that way when you bought it? Just wondering if maybe the manifold to gasket was about shot, then a clean up with a power washer, or steam jenny took away what was sealing it.

[DanB53]

Sounds like #4 exhaust hanging open. That would explain the bang, when it runs out of gas. Hopefully the push rod just dropped out of the rocker arm when the valve stuck, and did not bend the push rod. Seems one of the other three should at least give a little poof, if getting fuel, and valves half way decent.

Had this tractor been sitting a while..?? From the looks of the picture in your avitar, looks like it was just painted/restored..?? Was it that way when you bought it? Just wondering if maybe the manifold to gasket was about shot, then a clean up with a power washer, or steam jenny took away what was sealing it.

It sat from the early 70s until last year when it was pull started and ran for an hour by the guy I bought it from. That is as long as it has run since the 70s. He just did a quick paint job to make it look a little nicer but that was all he did other than an oil change. I've done the only mechanical work since it was parked 40 years ago. If fixing the valve doesn't help I will pull the manifold. I haven't done any powerwashing or anything like that to it.

[DJ54]

Could be the valve stuck after he had it running too. And if cleaned for the paint job, may have unsealed an old intake gasket.

After removing the valve cover may tell you something too. Believe I'd check to see if oil is getting to the valve train, especially that end the valve hung up on.

Keep us posted..!!

[DanB53]

Here is a pic of what it looks like under the valve cover. There seems to be plenty of oil spread over everything. It is the exhaust valve on #4 that is stuck. Nothing seems to be broken or bent. What is the best thing I can put on it to free it up? I don't have any Marvel Mystery Oil but what else would work? Also there is a hole on the top of what seems like the oil dispersal tube near the end closest to the rad. Can anyone conferm that it should be there?

[DanB53]

I got the exhaust valve free. The intake was leaking slighly too. I did the leak test with compressed air on all 4 cylinders and all is good exept the exhaust on #4 isn't seating properly still. I got the compression up to about 70lbs on #4 but no matter what I try I can't get the exhaust to seat any better. I think once I get it running and rev it a few times it should knock the carbon build up thats holding it open out. But judging by what it looks like under the valve cover, I will go buy some Marvel Mystery Oil and mix a quart of that into the oil for the next couple oil changes to clean everything up.

[DJ54]

Could be that #4 exhaust is burnt too. Could have been hanging open slightly for a while, and burned. Possibly carboned up the stem and guide enough, it finally hung open. Moisture got, or is definitely getting in under the valve cover.

If it were mine, I'd pull that rocker assy. and clean it up outside the engine, but that's me...

And are my eyes deceiving me, or does the couple of spots/puddles of oil look milky..??

[DanB53]

Could be that #4 exhaust is burnt too. Could have been hanging open slightly for a while, and burned. Possibly carboned up the stem and guide enough, it finally hung open. Moisture got, or is definitely getting in under the valve cover.

If it were mine, I'd pull that rocker assy. and clean it up outside the engine, but that's me...

And are my eyes deceiving me, or does the couple of spots/puddles of oil look milky..??

Your eyes don't decieve you. There was a fair bit of water in there and red paint for that matter. The gasket is toast and let moisture and the new paint under the cover. I think the water just seeped in through the gasket when I flushed the coolant passages in the block via the thermostat housing, I didn't see any water when I did the oil change when I first got it. I definitely will tear into the engine but I would like to get it fired up to see what all is wrong first. I cleaned the rocker assembly quite a bit, in place.