DBG Roosa- Master on 4020

I"m hoping some of you with experience can answer a question about my DBG Roosa-Master. Yesterday I started my '65 4020 and it revved up to about 1500 when the throttle lever was set at idle. I gave the foot pedal a tap and the engine settled down and I used it for a couple hours on the hay rake with no problems. When I was done raking I shut it down and restarted it and it did the same revving up thing. So, I presume the flex ring is going to pieces. My question is this, is it possible to replace the flex ring with the pump on the tractor. I internd to take the pump off this winter (when the tractor is getting a valve job)and completely re-seal it and whatever else it needs but I really need the tractor for the round baler in the next few days as my 730D struggles in that application. I can get the flex ring in a couple of days and I have Deere manual #2045 enroute (which I suppose will answer my question) but wanted to see what those of you who have been in these pumps have to say. I want to put the solid weight retainer in and eliminate the flex ring but will do that when the tractor is down for the valve job. Thanks for any info/advice.

Ted K

It would be next to IMPOSSIBLE to remove and reinstall the head and rotor and governor assembly with the IP in the installed (vertical) position. ('Cuz the governor would fall apart at any attempt to lower the assembly down into the pump body.)

Have you examined the return fitting/pressure regulating valve or looked into the timing port for coffee-grounds-like debris that would indicate a disintegrating flex ring?

Your problem could also be a sticky metering valve or worn governor linkage.

It would be nearly impossible to do it on the tractor because the weights in the the weight cage would want to fall down because the pump is vertical. You cant put the weights in the pump before either because of the snap ring that holds the weight cage on the rotor. You will need the pump removed. Remember to time it before removal. Check the return restrictor fitting for debris to be sure this is the problem.

It would be impossible. But if it were possible it would take longer than removing the pump.
Usually the pieces of the plasticast ring cause the metering valve to stick.

are you adding any extra lube to your fuel if not it may be sticking the metering shaft try 5% bio diessl

Thanks for the replies guys.

The service manual and seal kit and flex ring are supposed to be here by Friday. I didn"t want to tear into it w/o the manual.

Until then, I"ll check everything you all mentioned. I have had the little timing cover off in the last month or so to sheck the timing and noticed NO coffee grounds as you mentioned. Haven"t taken the return line off yet to check there.

I"ve not added any extra lube to the fuel so the metering shaft sticking could be the problem. Are these older pumps that sensitive to the low sulphur fuels we get these days? It"d be great if a can of some additive would be all it needs....

I agree with the others on the sticking issue. I can't believe there is a 4020 out there that still has the old style gov ring. By now they have all been converted to the steel cage/ring assy. If it hasn't been then you should do it if you tear into it. Can't believe someone would just replace it with the same old junk.