Folks,
I am having a right old performance trying to get this tractor to fire up.
Long story short basically some time ago I had to replace the seals on the throttle spindle which meant going in to the governer housing, the machine sat for almost a year in the owner's yard. Tried to start it and no go, anyway it seemed as if the rack had stuck. So went back to it yesterday with the intention of removing it but thought I better try one more time, plenty of duck-oil and a squirt of engine oil in around the plungers and got everything free again.

Rebuilt it in-situ with new gaskets, primed ther pump up with the hand-primer and also had the throttle lever all the way forward with all 6 injector pipes slackened off with diesel flowing out of all ports. I also bled the governer housing by undoing the little 1/4" bolt. I also verfied the pump timing is correct.
Cranked the engine over with the lions at the injectors slackened off and all we seem to get is a dribble of diesel and find the same at the pump outlets as well.

The tractor sounds like it is trying to run but just doesn't pick up.....that sort of sound they make when "on the next crank they will start". Even tried with a sniff of ether and it didn't help push the ball over the lion.

I had a length of clear pipe supplying diesel to the filter inlet on the pump from a seperate tank thinking maybe there wasn't enough head of diesel, with the pipe full of diesel I saw that air bubbles were coming up it from the pump as if it was displacing air.

when I pump the primer it always seems that the first couple of pumps are easy, then it stiffens up.....as if the main pump body has lost pressure.

To me it seems as if the diesel is too low for the pumping elements to pick up....as if the diesel is draining off slightly.


Any suggestions?


 

 

Valves on the priming pump may be bad. Did you have the throttle control pulled back enough when you tried to start it?

That appears to have the constant bleed valve. Check and see that the internals are working.

@ Rome KG.....yes, throttle lever right back

@Old Magnet - funny you should mention it but that was the very last piece I looked at before calling it a day ......it seemed to be in order....spring wasn't broken and the valve was the right way around and seating

You mention air bleeding back from the pump/s. Take the lines loose from the injectors and crank the engine to see if you are getting compression bleed back. Use a few drops of oil or fuel and look for bubbles indicating leakage.

@ O/M......you mean to indicate that compression gas is unseating the injectors?

Not unseating but leaking past injection valves and check valves or the capsules are not seating properly.....it happens, not often but has been know to happen.
You didn't state which model s/n D6D. I'm generally referring to capsule/pre-com injection, not direct direct injection.

OM....its a 20X 04340 (8A3204 arrangement) I believe its a 3306 motor

OK, so Direct Injection.
What do you have for fuel pressure?
If not compression back feed about the only other source for air intrusion would be transfer pump seals.
Your symptoms of priming pump seem normal. Should be some easy strokes until pressure builds to point where constant bleed valve opens.
Are you sure your getting full rotation of the sleeve metering shaft?

O/M.....well, there's no fuel pressure gauge fitted to this one.,.....just a blanking plug where one should live.

You mean the shaft that slides the barrels up and down the injection pistons?
It rotates nicely, the only thing I did notice on this was that on the "shut-down" position the action is positive, moving from idle to max speed the rack stay seems to sit freely - not a positive movement throughout the rev range realtive to the throttle lever, it does look like its the max speed (bearing in mind that we should never assume anything) my assumption is that the governer mechanism regulates the delivery openings throughout the rev range.