4020 injection pump irratic

I have a 1966 4020 Powershift with a stanadyne roosa master
style pump. Tractor has not been ran much in years and I
bought it put new filters on and it ran like a charm, then one
day I cranked and I noticed it would not start easy and had to
move throttle. Then it speed to 1800 by itself....ever since it
has not had the correct throttle response.. I have researched
and it sounds like the governer ring his worn out. My question
is can I repair this instead of costly pump shop and if so what
specialty tools would I need?
Thanks
 
Which style RoosaMaster/Stanadyne pump? Huge difference. Sorry but I can't recall which years had what. 4020s used the C pumps and the D pumps. C pumps have NO plastic ring to break. They often had/have governor and throttle issues due to wear in the rack and pinion gears getting stuck or wearing out. With them, sometimes all it takes to fix is to remove the pinon gear and flip it upside down. If you have a D series pump (DBG or JDB) - broken plastic governor dampers are common. But when they fail - the first symptoms are usually not what you describe. If it is a failed ring - it's not a highly difficult job to fix for a skilled mechanic. Usually takes around $50 in new parts.
 
My 72 model 4020 did that and it was just old fuel.It mostly sets around.I drained the tank and the last fuel to come out was black.New fuel and filter and it runs good now.
 

It's a dbg style pump .
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(quoted from post at 08:01:23 09/21/14) Can I get parts from Deere or pump shop? All they want to do is me it's needs building..

JD stopped selling most inj pump parts many years back. You can order parts here www.usdiesel.com/
 
Follow up on roosa master jdb pump. I took the return line off at elbow with check valve and nothing,,, very clean. Blew through the line fine. Then took side cover off pump with two screws where timing marks are. No black terds or sign of trash. Could a restriction on the pickup in tank cause irratic speeding up? Or just die out?
Thanks,
Shawn
 

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