Injector pump problem

[nealfris]

Hello all, I'm new to this site. I've been looking around all the tractor forums. What a wealth of info, not to mention a lot of fun banter!
Here's one for the orange people, no one else seems to know how to answer.
I bought a L3000DT last summer. The previous owner disclosed a sticking throttle problem. The dealer said it was a pricey fix. He learned to live with it.
I have too till now. Dash lever if free of the linkage on return to slow. Pulling up on gas pedal brings it to idle.
I have sprayed everything with PB blaster. And I mean everything! The last owner had it for a one year landscape project. He did no maintenance. Tractor only had 187 hrs and is like new. He just didn't do anything. Anyway I digress.
I removed all linkage at injector pump shaft. All linkage is free, injector pump shaft will not return to idle. I've sprayed PB on it for 9 months.
I have decades of back yard mechanic knowledge but I know nothing about diesels.
Can anyone tell me how to properly make the needed repair???

Thanks,

Neal

 

[eserv]

This is really a very simple fix but requires some dexterity. Remove the 4 fasteners holding the throttle lever plate to the engine, lift up the plate and carefully remove the throttle spring from the lever on the inside. Be VERY careful that you don't drop the spring into the engine or you'll be removing the front cover! disassemble the throttle plate and withdraw the throttle shaft from the plate, clean it up and reassemble with a light oil. Problem fixed!
I thread a small wire through the spring before I remove it to prevent dropping it into the front cover.
You will not change any sttings when you do this as long as you don't stretch that spring!
Ed

 

[nealfris]

Ed, thanks so much. I was hoping it was that easy. I guess my patience in waiting for advice paid off. It would be just like me to drop that spring!!!
Does that plate have a gasket that I can save if I'm careful?

 

[eserv]

Yes, it has a gasket. it usually comes apart easily though without damaging the gasket.
Ed

 

[SuperCharged]

I've got a 1977 B6100 with a similar issue. I can lightly touch the end of the throttle shaft and push it to the idle position. Could this be the same fix? And if that throttle shaft in the cover plate is sticking, does that affect the governor operation?

Thanks for your help. This diesel stuff is new to me! Only about two months now.

 

[SuperCharged]

Thanks. Now I just have to find the time to work on it!

One more question regarding the governor. I've looked at the parts manual and read up in a service manual, but I still don't completely understand how the throttle and governor work. I get that the balls move out with centrifugal force to move the second fork which is attached to the injector pump rack, but how does this happen at different throttle positions? I assume the pump gear doesn't move axially, but the second fork has to move forward in the engine to move the rack forward and pump more fuel for higher speed. But at higher speed, the balls are the furthest position backward out of the gear, right?

Ok, that was more than one question. But I am really interested in how this works.

 

[SuperCharged]

Update: the o-ring on the speed control shaft on the injector pump was swollen and hard. Removing that solved the problem. I still have to get a new o-ring, so I am anxious to see if it stays "fixed" with the new o-ring.

But I am suspicious that the governor is not working exactly right. My Dad (300ZX on this forum) has a B7100 that when idling and the 3pt hitch is raised, speeds up in response to the hydraulic lift. Mine doesn't do that. But at normal operating speed, I don't have an issue with the mower kicking on or pulling hills.