Oil & Fuel Another dk stuck at full throttle.

   / Another dk stuck at full throttle. #11  
If I remember right, some here thought it had to do with the shutdown solenoid slamming closed to hard on the 05-08 models, damaging the gears. Not bad fuel

Here's what I think I know about this.
(1) The "old" version of the stop solenoid used an external solenoid on the right side of the engine and that solenoid physically operated the external, manual stop linkage. There was an 8-sec 12v pulse provided by a timer relay that powers/operates that solenoid when the key switch was turned off. The force from that old version was limited to the force produced by the solenoid under power.
(2) A "new" SS version was phased in at different times between 2005-2008 with different models getting the new version at different times. I think the bigger engines got the new version first. This new version uses a solenoid on the front of the engine. That solenoid pushes directly on the IP rack and is spring-loaded to force the IP rack full aft (off/zero fuel). For the engine to start and run, a 1-sec 12v "pull" pulse to the solenoid retracts the solenoid (freeing the IP rack) and continuous 12v "hold" voltage keeps it retracted until the engine is shut down (via the key).
(3) I suspect the failures are caused by the momentum of the new solenoid (built up by the spring force) as it smacks the IP rack on shutdown. The rack (and the gears and plungers) should be free to move but if one of the plungers is under pressure (injection stroke) as the solenoid smacks the rack, that plunger could resist rotating and break a gear tooth. The IP plungers are lubricated by fuel so fuel quality could be a factor but I doubt it. Otherwise IP plunger wear would be a common problem.
 
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   / Another dk stuck at full throttle.
  • Thread Starter
#12  
The plunger theory, is very possible. I power washed the engine and spent a few minutes on it yesterday, have the oil fill side cover off along with the rack spring and solenoid, the rack will not move at all and I think I could see a small piece of a gear tooth laying under the rack. I had some other stuff to do so I didn't go any farther with the disassembly yet.
 
   / Another dk stuck at full throttle. #13  
... have the oil fill side cover off along with the rack spring and solenoid, the rack will not move at all and I think I could see a small piece of a gear tooth laying under the rack. ...

Pretty convincing evidence of a broken/jammed gear tooth. I'll include this in our database of IP events, if that's OK. Knowing the build year and engine hours at failure would be of interest.
 
   / Another dk stuck at full throttle.
  • Thread Starter
#14  
I'll have to look and see on the build date and double Che k the hours but was thinking it was about 210
 
   / Another dk stuck at full throttle.
  • Thread Starter
#15  
Well finally had a chance to finish removing the pump and pulled one gear, found two teeth broke off. One was still compete but the other was busted into a few small pieces and stuck in the other teeth of the gear. Now to find four new gears and he should be back up and running . Is there a part number for the gears that anyone knows of? The build date is April 2005. With 218 hrs.
 

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   / Another dk stuck at full throttle. #17  
There may be someone out there that has the P#.. if not.. see post #5.
I have the complete rebuild program for all things Zexel.. and I'd be happy to share..I just need to know the P# of the pump..
My #'s don't cross from tractor mdl or engine mdls.. ONLY ZEXEL.
 
   / Another dk stuck at full throttle.
  • Thread Starter
#18  
Ok thanks, the number stamped on the tag off the pump is 50809
 
   / Another dk stuck at full throttle. #19  
That's the serial #.
Wire wheel the edge of the mounting flange all the way around the pump.. the #'s are stamped into the housing..
Normally the pump # is at the opposite end from the serial #.. sometimes their on the other side of the pump.
 
   / Another dk stuck at full throttle.
  • Thread Starter
#20  
Will do , thank you. Figured it might be stamped in the casting someplace under the thick paint. :)
 
 
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