I need help in trying to get a d4 7u to crank. Dozer has been sitting for several years. I am able to turn engine. I know to drain all fluids and replace. My concern is the pony motor exhaust did not have a cover. What would be the best way to check for water in cylinder?

Just open both the petcocks under the spark plugs and roll the pony over.

Welcome: Does the pony turn at all? It should have petcocks on the bottom of each head, open and check for any oil/water/fuel that may have gotten inside. Drain them.
If it does not spin, then you might want to squirt some lube into the spark plug holes or even remove each head to see if you have stuck pistons or anything ugly inside.JM

one thing to consider is the pony exhuast may be rusted out and can lead to dusting the main engine as it runs through the intake manifold. just some thing to check once you get it running. a borescope camera can come in handy. that why its important to keep them covered or have exhuast flaps fitted

What can I disconnect to allow the pony motor to have something stopping it from turning after removing heads? I have removed seat, metal cover over main hand clutch ( oil cup on clutch dry and full of dirt), metal cover steering clutches. Inside steering clutch access brakes are rusty. I have moved the dozer and it move fine. I want to see what all works and does not work. Any thoughts will be much appreciated.

Hi Gary, if the pony crank does not move either direction best remove pony, from rough memory must remove pony to get pinion clutch unit out as it hits drive gear? (can't remember 100%), only a few bolts around the motor, be sure to get the ones behind the diesel head/block area they are hidden, this way you can get the junk back out of coolant gallery to pony in fly wheel housing it bolts to and under the pony, yes it is heavy to lift out by hand best get a helper or use lifting device, you can get bottom gasket from cat or make one up, make sure to change seal to diesel head as you process starts again to sort that later on.I hope pictures come thru to give rough idea. [attachment=71798]DEE2BE9B-0A88-4F2E-87BB-D02CFBE35544.

I believe if the thrust bearing on pony crankshaft has to much play the gear on the magneto hangs up and stops pony from turning. Which breaks thing like mag gears.

Or am I remembering wrong again as I don't have a D4.

yes ray that can happen. as the pilot engine is inline with the main, when its not running the crank flogs back and forth with the motion of the machine and the weight of the flywheel works it through the main bearings which are actually bushes and are also used to set end float. this bushes are only held by dowel pins that are known to break or wallow out allowing too much end float and a resulting harmonic vibration which shatters the mag gear and/or bends the mag shaft(ours did both). they also wear as the riding surface is only narrow. the bushes are turned to length before install to set the end float. (its a poor design proper taper roller bearings would have been better choice)

Neil fixed his by making some bronze thrust washers that mounted on the block casting and the crank and took the load off those bushes also instead of it wearing against a area 1/4 inch or so wide they had a area 3 times that.

a old farmer told us to make a couple of wood wedges to support the flywheel and prevent it walking through the bushings

As others mentioned, check the magneto. Some have been known to bind up after chipping a gear tooth, or the mag itself is toast (I've seen some here damaged by high revving).
It that isn't the case, I would take a wooden block and gently whack on the pistons. JM

Quick update. Right clutch full movement and pony motor moving some in both directions. Can pony motor cylinders be honed without removing pony motor? If pony is removed does cal have to be removed?