MF 431 - Injection pump problem? - sat and then fires off to high rpm

[Jason1010]

A day later and still starts with high rpm. On/off several times. I'll give it some more time and check it again.

 

[claggstractors]

Yeah, sometimes it takes a while if a piece is really stuck and sometimes no matter what the pump has to pulled and gone over. I've always hated how Perkins set these up though.

 

[JWR]

This is fairly wild. Is it in a place where you have lots of space? I would be tempted to start it up & head off in lowest gear and run around a bit on it. Vary the load by braking it off and on. Whatever mechanism is supposed to actuate the governor may get jarred loose by the "normal" up and down call for governor action. Obviously ticklish to do this but might work. Of course make sure the engine does not overrev in the process. Your only shutoff mechanism is the key, right ? You probably should check the owners manual about a shutoff mechanism too.

 

[ROUSTABOUT]

You could back the throttle screw off so you can kill it that way, or slow it down.

 

[Jason1010]

Well sportsfans, same thing today as previous.

I'm pretty confident that the metering valve is stuck open, which the governor nor throttle can pull back in.

With the way the engine runs up, I don't want to risk engine damage trying to even back it out of the shed.

Throttle is fully closed and moving the throttle does not affect it going wide open on start up. Disconnecting the throttle from pump does not change anything. I see nothing in the manual nor on the tractor for a secondary cutoff.

I think I'll continue to let it soak some more but start removing sheet metal to prepare for pulling the pump.

In the meantime, willing to try other suggestions. Thank you all again for the replies.

 

[thepumpguysc]

Unless the magic potion frees up the mv(hope so) your destined to pull the pump..
READ THE MANUAL..
THE TIMING IS CRUCIAL ON THAT PUMP AND ENGINE.!!!
If the engine is not set correctly when you pull the pump, you’ll never get it to run right when you put it back on..& u only get 1 shot at it..
Once u break loose the locking bolt for the pump drive shaft.. (timing) and start the engine or crank it.
There’s no putting back the timing from the fuel shop(lock timing)..
If it’s not right, the pump has to go back to the shop and put back on the machine inorder to set the timing again..($$$) it’s not a simple procedure, so u will b charged..
I had a customer once that screwed it up 3x.. and was charged 300.00, 3x..!!!

 

[claggstractors]

Unless the magic potion frees up the mv(hope so) your destined to pull the pump..
READ THE MANUAL..
THE TIMING IS CRUCIAL ON THAT PUMP AND ENGINE.!!!
If the engine is not set correctly when you pull the pump, you’ll never get it to run right when you put it back on..& u only get 1 shot at it..
Once u break loose the locking bolt for the pump drive shaft.. (timing) and start the engine or crank it.
There’s no putting back the timing from the fuel shop(lock timing)..
If it’s not right, the pump has to go back to the shop and put back on the machine inorder to set the timing again..($$$) it’s not a simple procedure, so u will b charged..
I had a customer once that screwed it up 3x.. and was charged 300.00, 3x..!!!

Also, don't forget to pull the timing pin before reassembly. @Jason1010 I got a copy of the Perkins manual in case you need it.

 

[JWR]

... thinking over the past 16 posts... this is an 18 or 19 year old tractor with less than 300 hrs on it. It was either rebuilt or mothballed for an extended period. Maybe both. I can't see anywhere that the OP tried to start it up and run it a bit before attacking the machine doing 10 or 15 things to it which (while understandable) complicates the evaluation. Almost gotta suspicion that something done during the rehab process was the culprit. Isn't this also among the early years of the 3 cyl Perkins in MF tractors? Surely the pumpguy in Post #16 knows more about this than all the rest of us combined...

 

[claggstractors]

... thinking over the past 16 posts... this is an 18 or 19 year old tractor with less than 300 hrs on it. It was either rebuilt or mothballed for an extended period. Maybe both. I can't see anywhere that the OP tried to start it up and run it a bit before attacking the machine doing 10 or 15 things to it which (while understandable) complicates the evaluation. Almost gotta suspicion that something done during the rehab process was the culprit. Isn't this also among the early years of the 3 cyl Perkins in MF tractors? Surely the pumpguy in Post #16 knows more about this than all the rest of us combined...

Fourth sentence he states he tried starting it without doing anything. Then he checked out the fuel supply. Once that was fixed, it started but was going beyond governed RPMs. I thought it was the governor that was stuck, but @thepumpguysc pointed out that it was the metering valve. Learned something new there myself. This is also one of the newer Perkins designs. The magic potion(Stanadyne and ATF) is just something I've used over the years myself to free up stuck injection pumps for further diagnosis. Sometimes it works, sometimes it doesn't.

 

[JWR]

Thanks for the corrections Claggs. Good info. I had missed where he had tried it without doing anything. My oversight.