On this engine it's the intake valves that open with the compression release. Don't think any are sticking. I've got the exhaust manifold off. Too bad the exhaust valves are not visible. Need to find my bore scope to see the exhaust valves. Figured if exhaust valve was leaking I should be able to hear or feel it spinning it with the manifold off. All 4 blew out about the same amount of air. And no hissing sounds. I made an adapter to connect my compression gauge. I used the adapter for a Perkins and I think the older engine. Made a bracket that bolts onto the head with the 2 head bolts on each side of the nozzle. The retainer for the gauge is held by the bracket. A bit difficult to work with. But it works. .Only checked cylinder 3 so far. It has 380 lbs. Was running out of daylight and had to get some wood in the house. I'll probably check the others I'm the next day or two. Finally got the fuel filters too. Don't really think they will fix the fuel pressure. The old ones don't appear that bad. But I'll put new filters in. And if it proves me wrong, I won't mind it at all. If it's not the filters, I'd say it the transfer pump. Hope not. I was quite surprised the price of them. 

Mine reads zero. However, it doesn't run like it. I just purchased it. So I've not had a chance to use it. Seems to have some power. Had a tree get blown over and was caught in another tree.. I hooked a chain to the fallen tree to pull it from the other tree. It was in a decent sized sugar maple approx 12- 14 for inch diameter. Don't know how it was holding on like it was. There was a branch laying in the crotch 20-30 ft up. Was expecting it would come loose or maybe break the chain. Heard a crack and down came the maple. It snapped the log off about 10 ft off the ground. The cat didn't even strain. So seems like it should push. Now I find it's got a dead cylinder and no fuel pressure. So it should really run when I get it going.

Didn't get compression checked on all cylinders yet. Did check #1. It has about 360lbs. which is less than #3 at 380lbs. I'm going to have to assume it's not compression causing the dead cylinder. Only thing I can come up with is it must be injection timing. Guess I need to look at the lifter hight adjustment on the pumps. Maybe I used the wrong mark on the flywheel? Most manuals I've ever looked at showed a picture of the mark. Would be nice if Cat would have. Only thing I found was a small hole. By looking at the valve position, it was somewhere near correct. Haven't found much on this. It's been vague. Read something giving me impression there's 2 marks. One for 1&3. One for 2&4. And sounded like mark is 1&3and 2&4.
Got the fuel filters in. And it changed nothing.

Yes, there are two sets of timing marks.

To check your injector pump: Remove the 4 pumps and check the height of each lifter.
The measurement should be: 1.736" from the top of the housing to each tappet at TDC of each lifter. Use a depth micrometer. Probably need to remove the paint on the top machined surface to get an accurate reading. Adjust them by turning the bolt on top of each. Better to do on the engine to be sure if any gear lash is taken up.
Check the length of each injector pump plunger too: 2.6575"-2.6577" Use a 2-3" micrometer.

I had the fuel pump body from the 7U I did 2yrs ago out and my bench. I carefully checked each cam follower (tappet) for proper lifter adjustment. I had a degree wheel attached to the camshaft and used a dial indicator to know when reached TDC. I never rechecked it after I installed it on my engine to see if any changes with gear lash. Tractor starts and pushes pretty good.

If I have it running at low idle, as low as it can, every few rotations it pops out the exhaust. If I loosen the injector line on #3 cylinder it stops popping. Once loosening #3 seemed to decrease rpm very slightly.

I now have all four cylinders firing. It was the injector timing. Adjusting the lifters did it. Thanks again to everyone who assisted. Now if I could get some fuel pressure. I'm pretty sure I need a fuel pump. It looks good on the inside as far as surfaces go. There is no scoring except a slight bit where the gears ride on the plate. There is a lot of play between the gears. It turns and has a new bypass plunger . Haven't had much luck for a replacement or rebuild kit.

Well I thought I had 4. Now number 1 isn't firing. Guess I'll check the lifter height on that one. As for the fuel pressure, think I may have 2 bad gauges. I noticed if I opened the bleeder on the fuel filter when engine is running, there was more pressure than when not running. Connected another gauge. Wasn't right for the job. 0-120 with increments of 10. At idle there was nothing. But with throttle wide open, almost 10. So I'm going to say that's a win. Now to order a new gauge