Thanks Jay. How can I miss? I've got a great team behind me here. When we beat this thing, and we will, I'll be sure to post the solution so everyone can learn.

Well, the coil came a day early so I got that installed. No improvement, still sounds the same. On the lighter side, now I have a spare coil! Jon mentioned muffler back pressure so I pulled it off and inspected it. No loose baffles and I could easily blow air thru it in every direction with a blow gun on the shop airline. Since I had the exhaust out of the way, I thought I'd check valve adjustment. All four where in spec so no joy there either. While running the engine out of the tractor and clamped to the bench I eliminated any driveline problem causing this. One new symptom I did notice the engine won't rev very high. I ran the engine while holding the throttle shaft to control engine speed. I wanted to check governor action so I held the throttle open and felt the gov pull the throttle back -- good. As I held the engine at full throttle OVER COMING THE GOV, the engine failed to rev up much past what I'm guessing would be about 3000 or so. That's a guess. The air cleaner was not on during the run. I am now wondering if someone had this engine apart and did not time the cam to crank correctly. It acts like maybe it's valve timing. Jon - what do you think? Sorry I didn't get a video of it running for you yet.

Have you tried swapping the carb AND intake from the 2072 to see if the engine performance improves?:bigthink:

I swapped carbs but not the intake itself. The carb made no difference either way. The 2072 ran good with the 782 carb and the 782 skips with the know to be good carb from the 2072. I have had the intake off the 782. The PO must have been playing around because the intake to head gaskets were shot and had some silicone smeared on them. When I first spotted the loose intake and bad gaskets I thought I had found the problem. Nope!
Since replacing the manifold gaskets I have spayed ether around the joints to check for a vacuum leak. None found.

I read your earlier post regarding the carb swap. It cannot hurt and it does not cost anything to try the intake swap. You may find the problem or not...but it is easier than splitting the engine and checking the cam timing!

I agree Beth, there is a possibility that there could be something lodged inside the manifold blocking flow. I'll check it out tomorrow.

IIRR,
While watching the valve action in the tappet boxes:
At TDC on the exhaust stroke, the exhaust is just closing and the intake is just opening with appropriate equal overlap of both valves.

You can look in the spark plug hole with a pea light and see the piston top, @ TDC, as well as feel it as you turn the crank slightly in direction of travel as it gets easier a bit as you achieve TDC, as both pistons are @ TDC,and have stopped, before they start to change direction.
I hope I haven't lost you?:bigthink:

This should tell you if the cam is timed correctly.

Nope you haven't lost me. I had one head off and watched piston TDC and valve action during all 4 strokes. As best I can tell it looks ok visually but still, who knows, one tooth off?

I don't know...... I'm thinking.

I agree with George, on how to look the simple way to see if the cam is close. That's a good way..... but if it's just a tooth off, it may be hard to see.

The deal with it not being able to rev up..... I don't know. Stan, as many motors as you have worked on I think you should be able to judge RPM, so I trust your guess. I agree that timing is possible. So is lack of fuel, but since you have switched carbs with no change, then it would have to be a supply issue, which is possible, but unlikely with the other symptoms. Cam timing seems to be the only next logical step with the diagnosis you have done. Just not much more could be wrong.

Vacuum leak is possible, and would cause the same symptoms, but it seems unlikely as there are only 3 gaskets to leak, and they are all new. I have seen warped parts though that wouldn't seal. Your leak check with brake cleaner should have yielded a result if there was an issue though.

I'd still like to hear this thing running.

If I have a chance tomorrow, I plan to pull the intake manifold off and check to see if something is lodged in one of the runners, a washer or something that might disrupt the flow to a cylinder. So much seems equal though. I will say one thing, I got time. I don't care if I have to take this hunk of aluminum down to every last nut and bolt, inspect and reassemble. I will beat this thing, I'm just trying to do it in a logical manner. I'll try and get some video footage for you Jon.