question on starting a d-6 dozer

I am working on an ru-d6 that has been parked in the hills for 10 years.I did start it twice but found problems and had to fix them.
Now for some reason I can not get the engine to start before it throws out the pinion gear.
I did realize after the fact I have the pony motor revved up can that be the problem.Maybe its going to fast and when the motor starts to pick up it has to much centrifugal force and throws out the pinion gear ??
...
engine turning under compression it has white exhaust then when I add fuel it go's black so it's getting fuel even thou the fuel gauge is not working .I did bleed the injectors they all are squirting fuel.
I can use any tips or info
thanks John

You could check your air filter he maybe plugged

You can try holding the pinion in manually to get it started but that won't work long term before there are bigger problems. You need to investigate the latching mechanism and whether or not the engagement sleeve has lost its attachment bolts or the latches are either out of adjustment or worn out.
Welcome to the world of pony motors.

Google, acmoc.org, that's the Antique Caterpillar Machinery Owners Club, they will be able to help you, there may be way to increase the tension on the throw out of the pinion gear. On my D4 you reach down into the case with a long screw driver, some one at the ACMOC site will know for sure about your D6..

I think I might have had the pinion engagement lever down after I engaged it.I should have left it up .I will try and see if that was my problem and
also not rev up the pony so much.
Thanks for the replies

if the pinion latches are latched the pinion engagement lever will flop up and down with no resistance---if the pinion latches are releasing you can hold the lever up to keep them engaged but as OM said you don't want to do this too often as it will wear out. The latches can be adjusted by tightening the release springs---i don't think the pony rpm makes any difference on the latches releasing---its the diesel's rpm that does that

Is this a 3 cylinder diesel, your post with the "R U", RD maybe, that would be a 3 cylinder, with the vertical 2 cylinder starting engine, vs the later 6 cyl and horizontal starting engine. Either or, same principle.

The book should describe the adjustment, 1/2 or 1 turn on the screw = x amount of rpms, so you can adjust when the centrifugal force kicks out the latches, sounds premature now. Check for mechanical problems first like Old Magnet says, not sure if you have an inspection cover on that one for access, if all is well in there, might just be the adjustment needed.

What you do not want to do, is have the diesel over speed the starting engine, by not having it adjusted properly, so be careful with that part of it when working on this, shut it down if it wants to take off, take the air breather pre-cleaner off, and have someone ready with a clean piece of board to block the air to the motor, have your hands ready on the levers, whatever it takes to avoid a problem as direct electric start or a starting engine rebuild could cost you.

Starting engines like fuel and spark, plenty of each, and do use care with its crankcase oil, check for gasoline contamination/thinning, change if its even questionable, with care these work nice, but they do require maintenance to work properly. I typically mention these kinds of things for the benefit of anyone new to these, so just in case you are, good to know.

Ok got it going owner came by and showed me the trick pony motor on idle when you engage the pinion then he revved the hell out of the pony then added the compression and it started.Now I know the trick of starting this dozer funny thing I had started it twice before then.

the pinion clutch has a brake on it to stop the pinion from turning--pull the clutch lever all the way back to apply it

I did just that but for some dumb reason I put the pinion engagement lever back down after I engaged it.
I was confused on how it worked but now I got it after a few youtube video's of people working on the internal parts.
We have a cat grader with a pony motor on the dairy but we always pull start it.The pony worked when we bought it years ago but he never wanted to use it.