D6 9U Pony motor snag

I went through a very analogous situation last year and it turned out to be the magneto.

Doesn't seem possible the mag could do it but it did.

I would have had the whole darn engine apart until the guys at Dayton Tractor led me straight.

Drain the coolant down and remove the heads, then you can observe the valves and check the pistons for excessive rod slop much easier this way. If you have a valve issue you can have the tight spot symptom you are describing. I any case the head gaskets can be re-used and you can visually check your bores, valve operation, etc. The next step if you can't find anything wrong is much more work but remove the heads first and go from there.

It did actually fire a few times while cranking so I'm reasonably confident the valves are working and my rod slop appears to be acceptable based on what I can see through the spark plug holes. I was wondering if I could re-use the head gaskets so that is good news if I have to pull them. I will clean and lube the mag and see what happens there, it has great spark (shocked the heck out of me a couple times now). I need to get this machine running so I can get it on a truck and headed home. Guessing I'm going to have to pull the pony and go through it based on the bearing play on the crankshaft, just hoping it is good for a couple starts first.

Thanks!

Do not ignore the suggestion to check the mag. Could be a problem with the impulse mechanism. It should start out in the retard position and automatically shift to regular timing as the pony picks up revs. Could be that is what is causing the bind as it attempts to run.

Great news, after cleaning the mag it turned out that Joe was correct. I found that the exhaust manifold for the left side cylinder has a 1" hole at the elbow. After draining the coolant and pulling the head I found that the cylinder had made a hockey puck out of mud. Once I clean the cylinder up, bolted the head back on, and put the coolant back in the pony roared to life after only a couple cranks! In addition the diesel rolls over and even seems to have good compression based on how hard the pony labors. I let the pony crank the diesel for a couple minutes at low idle, the diesel pegged the oil pressure and fuel pressure gauges.

Now my new problem. The throttle lever on the side of the injection pump won't move more then a fraction of an inch. I removed the side cover on the injection pump and checked the rack to find it appears to move when nudged left or right gently, at least it springs back to the off position. With the engine turning over all the pumping plungers work up and down. So now I'm looking for advice on what I need to take apart to free up the throttle lever. I'm starting to get excited as it looks as if it might run if I can sort out the throttle lever problem. Open to suggestions.

Thanks!

Have you disconnected the linkage at the fuel pump end and tried moving it. If you are half lucky it is stuck where it pivot on the air cleaner.

I wish it was that easy. My linkage is all free it is seized up in the pump itself. Thanks for the thought however.

Linkage moves, Rack moves. So it maybe a little rusty inside the Governor Housing? If it was left in the "Fuel Shut Off" position, then it maybe hanging up on the Shut Off Detent. Its earlier in the morning without a Manual nearby but I am pretty confident that I am thinking right.