Governor, RPMs, question

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Farmallgray

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I don't know if you guys will be able to relate to this or not. I'm working with a 3cyl Kubota in a pulling tractor. The pump is similar to a Bosch A or P but the pump housing is built into the engine block.

I'm trying to get more RPMs out of it. I have removed the screw that limits the rack travel and the screw that limits how much the governor spring gets pulled. I also lightened the governor fly weights.

Stock was 3200 RPMs NA and I'm now running about 4600 with 38# boost. It has a recall tach. I'm still running the stock pump and injectors.

I'm trying to determine if my RPMs are now being limited by fuel, or still by the governor. In other words I'm trying to determine if the rack is opening up the whole way or if the governor may still be holding it back. I tried a stiffer governor spring and it didn't make much, if any, difference.

One odd thing is that just driving around the yard it will only turn 4100 RPMs but under load hooked to a sled it will turn 4600. I'm guessing that the load is making it drive the turbo harder and making more boost which gives more RPMs.

I know it needs more fuel, but I'm trying to max it out before I spend a grand to have the pump and injectors done. My only idea for determining if the rack is opening the whole way would be to temporarily replace the governor spring with a solid link. That would allow my to override the governor and see if it turns any more RPMs. Any of you guys have any thoughts for me?
 
Is there a rack plug like on a p-pump? Might be able to fashion something so you can visually watch the rack, or put a dial on it so you can actually measure how far it moves.
 
Tate said:
Is there a rack plug like on a p-pump? Might be able to fashion something so you can visually watch the rack, or put a dial on it so you can actually measure how far it moves.
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The engine originally had a stop solenoid that I assume pushed the rack to close it. I made a cover for over the hole. I have thought about doing what you suggest. Maybe something that works like a pencil tire gauge and stays out. I would probably have to push it in after the engine starts because there is a light spring that holds the rack open for starting.

I was kind of hoping for something "quick and dirty". It was also suggessted to me to wire a couple coils or the whole spring to limit how much it stretches (it is an extension spring).
 
I ran tie wire through the gov spring on my L3A and basically made it not have a spring. Dunno the RPM because I dont have a tach, but its a bunch.
 
does anyone know which screw adjusts the rack and which one adjusts the governor. I have a turboed and intercooled rtv whith the same motor. there is one screw on top of pump and one one the front of the motor. ive turned the one in front of motor, if i go in a few turns the idle goes up...am I pushing the rack open?
 
The one out the front is for the idle speed. The one out the top limits the pull on the governor spring and therefore RPMs. As far as I know the governor is the only thing that controls the rack. There may have been some kind of solenoid out the back side of the pump, that mine no longer has. I bought mine as an engine alone. I assumed the solenoid was just for closing the rack to shut the engine down but I could be wrong.
 
mikeyrtv said:
does anyone know which screw adjusts the rack and which one adjusts the governor. I have a turboed and intercooled rtv whith the same motor. there is one screw on top of pump and one one the front of the motor. ive turned the one in front of motor, if i go in a few turns the idle goes up...am I pushing the rack open?
Click to expand...

The one on top of the pump controls your fuel delivery. You have to remove the whole thing and then shorten it to increase fuel delivery.
 
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