JD 6620 combine - still won't run - Part III

Posted by andy r on December 04, 2014 at 17:00:44 from (75.91.149.15):

First, thanks for all of the help. Here is what I did this mornng:
1) Ran fuel from tank sediment bulb - good flow
2) Ran fuel from sediment bulb outlet - good flow
3) Ran fuel from pipe going to electric pump - good flow
4) Ran fuel out of electric pump - good flow
5) Ran fuel out of end of pipe at injector pump (note - on inline pump combine, fuel from tank goes to injector pump first/hand pump is on side/also a mechanical pump runs off of injector pump) - pretty good flow - maybe rising 3/8" to 1/2" above pipe. Just a nice slow constant flow - not spraying everywhere. Reminded me of a low pressure drinking water fountain.
6) ONE TIME FUEL WOULD NOT GO THROUGH THE HAND/MECHANICAL PUMP ON THE SIDE OF THE INJECTION PUMP PUSHED BY THE ELECTRIC PUMP. ANOTHER TIME IT DID GO THROUGH THE HAND/MECHANICAL PUMP. I had ran the engine so maybe the piston in the pump was located at a different position and would not allow fuel to go through. Either time when the hand pump was used fuel would go through this item (hand/mechanical pump). I take it that the mechanical pump in this thing charges the filters and fuel rail in the injection pump.
7) Checked for fuel at end of pipe leading to filters. Like I said in #6 above one time it did not go through with the electric pump and one time it did after I had ran the engine. Always went through with hand pump.

Started the engine a few times today and actually I think it runs even less - maybe 30 seconds. Tiny air bubbles can still be seem coming in with the fuel at the bottom of the glass filter. Eventually the top of the filter has an air void exposing the outlet and the fuel stops going to the injector pump.

A couple have mentioned the hand pump plunger. I wonder if that plunger can act like a farm chemical injector in a spray mixing system, except in my case it is injecting air?????? The hand pump works OK - it is pulling and pushing fuel with each stroke. Could be a little loose. Still tightens down fine, which you would think out seal the air off. Looks to be a none repairable plastic plunger.

Could something be wrong in the hand/mechanical pump located on the side of the injector pump???? Remember fuel didn't want to go through and after I rolled the engine over it did go through. Looks to be a little piston in there with a push rod ran off of a cam in the injection pump. What all does that thing do??? Maybe the check valve too??? Someone told me they rarely cause problems.

Electric pump seems to be pushing an adequate supply to the engine. Is 3/8" to 1/2 " rise out of the pipe enough? After all I am not harvesting ... I am just idling. Can't take that much fuel at idle.

Thanks again guys. Eventually it will be figured out.

Replies:

• Re: JD 6620 combine - still won't run - Part III massey 333 05:19:39 12/05/14 (0)
• Re: JD 6620 combine - still won't run - Part III Bob 19:57:25 12/04/14 (2)
  • Re: JD 6620 combine - still won't run - Part III andy r 20:02:33 12/04/14 (1)
    • Re: JD 6620 combine - still won't run - Part III Bob 20:13:41 12/04/14 (0)
• Re: JD 6620 combine - still won't run - Part III Dieseltech 18:52:07 12/04/14 (0)
• Re: JD 6620 combine - still won't run - Part III RayP(MI) 18:23:01 12/04/14 (0)
• Re: JD 6620 combine - still won't run - Part III ben brown 18:12:38 12/04/14 (0)
• Re: JD 6620 combine - still won't run - Part III ben brown 17:31:59 12/04/14 (2)
  • Re: JD 6620 combine - still won't run - Part III andy r 17:39:40 12/04/14 (1)
    • Re: JD 6620 combine - still won't run - Part III 960 19:18:32 12/04/14 (0)

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