Seeking some advice,   
    I have a late D2 with factory direct electric start. Starter was working fine when I brought it in the shop last January to do steering clutches, brakes, and bevel shaft bearings.
            As part of that teardown I removed the starter in order to access the equalizer spring bolt...  gave the starter shaft a shot of fluid film where the gear slides and put it on the shelf.
Nine months later I install the starter on the tractor and and it won't spin the diesel engine over... it whirrs, it seems to engage, and you can see the engine fan try to move, but not spin over.
           If I engage the compression release it will spin the engine over... disengage the compression release and no go.
So I take it to the local auto elecrtic shop who has worked on these starters before and does a lot of work on heavy equipment starters and generators... he bench tests it and says it"s working fine, must be a solenoid or wiring problem on the tractor.
        I take it home and put it on the tractor and jump directly from the battery to the starter bypassing the solenoid, switch and wiring...  no dice, doesn't work.
So next I remove the starter and put it on another tractor with the same results...  I then take the starter from the 2nd tractor and put it on the original tractor it it starts just fine...  which confirms that it original starter is at fault, and not any other kind of problem with the tractor.
       Back to the auto electric shop where I explain my testing and results.    He agrees to look into it further.
Two days later I pick it up... he had taken it apart, armature tests good, every thing else looked good, and he replaced the brushes since he was in there even though he said they looked fine. Bench tests good.
       I take it home. put it on, same result as before... it whirrs, trys to turn the fan, but no go.
I'm stumped, as I'm sure is the auto electric guy.
       If the starter is ok electrically, is there something in the drive end that could be causing slippage ???
Thanks for taking time to read this, and any help you can provide,  Wayne

Hey Wayne, could it be that fluid you put on it?  Did you just dip some on it with your finger or pretty much douse the small end in it. I’ve never heard of a problem like that. But good luck.  Mike Hudson 

Those old inertia drive starters have a multi-spring loaded clutch built in to the drive. You may have inadvertently lubed the clutch. A good soaking in something like "brake clean" might allow it to recover.

Wayne: I hope it wasn’t the shop that rhymes with Obama! I had a customer take a starter for a TD6(I know, not the same) and it never worked right; I took it apart and find broken parts in it still as well as missing parts. All they did was change the Bendix and slop some black paint and their decal on it, for the sum of $500.00; they’re supposed to be the most expensive shop in your area. Major disappointment!
Good luck on your 24V starter. They are hard to come by. JM

Thanks everyone for your suggestions. I think Oldmagnet may have hit the nail on the head, because the starter worked fine until I lubed the drive end and put it on the shelf.
I ran this scenario past RotorBob the other day and he thought there was some kind of clutch mechanism in there, but wasn't certain.
I'll take it back to the autoelectric shop in Salinas and ask him to take it apart so I can clean it.

Been awhile since I dug into one of those and had it apart. Vaguely recall it being a one way dismantle and the Delco book states it is not a service part.

Old wrote:

Been awhile since I dug into one of those and had it apart. Vaguely recall it being a one way dismantle and the Delco book states it is not a service part.

  Oh Joy !!!     If it's not serviceable/repairable I will probably replace it with a 42mt and enlarge the hole to fit.
 

try soaking the drive end in a little shellite(aka solvent x55 or coleman liquid stove fuel) it works wonder for electromechanical switches. a photocopier tech put me onto it. rob said the number of copiers he has fixed with jar and some shellite to clean a dirty switch.

its cheaper than electrical contact cleaner and works just as well.
no need to dismantle you just need to hold it in the vise and hang small bucket so the bendix is soaking in the solvent.

and yes most starter motors do have a one way clutch in the bendix

remember to blow it out with air and let it dry in the sun so all the solvent evaporates.

Hi TK , do you mean LPG? kind of family in a fashion, is it liquid or a gas?