d950 injection pump problems

[snakeknuckles]

Hi: I recently acquired a Jacobsen 422D mower with a d950 bw kubota engine. Every once in a while when I go to start it, it runs wide full open (no governor) until I get it to shut down. (Key will not work) My usual fix was to push-pull on the fuel shut off solenoid and that would fix the problem. The last time it did this, I noticed the wires were melted to the solenoid and the thing wouldn't budge. I did get her shut down before she blew up. In retrospect, I should have just pulled the air intake rain cap off and suffocated her... The solenoid is indeed fried and costs $250 from Jacobsen dealer?? From what I have read online, I suspect that the solenoid is not the root cause of the problem. It sounds like the metering rack is sticking. Is that correct? Does anyone have procedure for disassembly/fixing this thing? Thanks for your suuport.

 

[bruceatlam]

I'll go on record saying that you don't even want to try it --- find a good fuel injection shop and have them look at it.

 

[janis]

Hey,
I ust want to add that I just changed an fuel filter on L1-455 and get air bulb, all the instructions abowe dose not help, the air bulb was befeore prime fuel pump and I spend lot of time whwn I found that, If instructions abowe dose not help disconnet tube from primr fuel pump un just turn engine a bit while pure diesel is comming out and than connect tube back.

Janis

 

[snakeknuckles]

Well I am only a little insulted by Vic's response... (There was no jury-rigging, just panic mode evasive action. I only regret not thinking quickly enough to pop the air cleaner rain-guard off and suffocate the damn engine before it over revved)
I, in fact ignored your advise slightly and took off the covers at the fuel shut-off lever and the throttle to see what conditions were like inside. It seems pretty clean in there and well oiled and it looks like all springs are in tact. Everything moves freely as far as I can tell. I may have mentioned that a perhaps-unrelated problem I had was a fried fuel shut-off solenoid which I replaced for almost $300! It seems this has been a problem on this machine before as the wire feeding it from the ignition switch was melted and that wire had been replaced... I put the new solenoid in and repeatedly started it to see if I could make the problems recur. In fact I got both symptoms to recur-the ungoverned speed runaway and the melting wire on the solenoid. Is there supposed to be some sort of shunt resistance in the solenoid wire? Every time the engine speed runs away, cycling the fuel shut-off lever resolves the problem. I think it might have something to do with the fact that the solenoid snaps the lever back so violently that the mechanism gets hung up.
I noticed that the throttle arm on the pump has an unused hole at the end that with a little bit of machine work can be connected to the fuel shut-off arm so that I could eliminate the solenoid altogether. What do you think of that plan?