Roosa-master pump

I have a 4240 with a M&W turbo and the Roosa master pump I was wondering if there was a way to turn the pump up or down relatively easily. It has a Pyro, injectors are good and I regularly clean the radiator. I enjjoy tinkering with stuff and was just curious.

Yes - but only to a certain point. The pump's capacity to overfuel is limited by the size and amount of the plungers it uses.

4020s uss "633" pumps - which designates 6 cylinders in the engine and two .33" diameter plungers in the injection pump that pump all the fuel. It can be a small C series pump (obsolete) or the larger DB or JDB pump.

Years back, when tractor-pulling was not big-business yet, I used to turn up pumps for local farmers to pull at the county fair - and then turn back down. For custom-tractors that are not intended for farm use, you can install a pump with either larger plungers - or - a pump with four plungers instead of two. DM4 series has four. JDB637 has larger plungers - i.e. .37" diameter.

THe original pump on the 4020 has a fuel-screw that was originally protected by shims to stop anyone from turning it up very much. They often get removed - so they may - or may not be there.

You can take the top-cover off the pump (on the side with a 4020), and reach in with an hex Allen wrench to turn the screw clockwise. If it will move 1/3 a turn - you can get an extra 5 or 10 horsepower and lots of smoke at full load.

Thanks. How do I tell which pump I have? Is there a number coded on it somewhere I can look at? is there a certain style I can tell which one mine is?

It has a metal tag on it with all the info. Tab is riveted on, just wipe the grease off to see it.

The obsolete C series pump is small and round. Electric shut-off uses a push-on connector and you can pull it off by hand. Throttle hooks to a long tube that extends away from the pump.

The DB or JDB pump is long and rectangular - and has a top cover (side cover on a 4020) held on by three bolts. If it has an electric shut-off, the wire is held on to this cover with a nut and stud.
Throttle hooks directly to a shaft that runs through the main body of the injection pump.

Here's a picture of the little round C pump -that hopefully you don't have.

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Here's are diagrams of the JDB or DB pump - which is still current and parts are still available for.

<a href="http://s104.photobucket.com/albums/m162/jdemaris/?action=view&current=stanadyneDB2_showingring.jpg" target="_blank"></a>

<a href="http://s104.photobucket.com/albums/m162/jdemaris/?action=view&current=banjobolts2.jpg" target="_blank"></a>

I will have to double check but I think I have the newer style. Are these that much better? what will it do different for me? and how hard are these to work on? could I do maintenence and repairs myself?

One pump model isn't newer or better than the other. In fact, the bigger pump was used on early 4020s, then the little obsolete pump was used mid-range, and then the bigger pump was used again.

The small pump design got dropped - and by the early 1980s - all parts suppport was discontinued. You cannot buy parts anymore. If you had a Deere tractor with the small pump that failed, Deere sells a change-over kit to put the other type pump on it.

In regard to you working on it? Well, many people on this forum jump up and down and have tirades about anyone working on injection pumps. The reality is - an injection pump is simply an oil pump with added controls. The big problem is - the repair information is kept somewhat secret. The company that makes the pumps only sells repair info to registered repair shops.

Repair info is available from other places. Deere still sells a manual - SM-2045. Same manual is available as a reprint from other places for $30. Parts can be bought by anyone from several places.

If you have mechanical skills, and get a manual, yes - you can work on the pump yourself with no special tools needed except for a few minor things that cost less than $20.

Will the bigger pump make more power? if so, how much horse is it rated to? Do I need to do any periodic maintenance to the pump to keep it in optimum performance?

The bigger pump uses the same size plungers as the small obsolete pump and is not capable of pumping any more fuel.

You've got the 633 pump with .33" plungers. The next size bigger - actually the biggest that Deere ever used with this model pump - has .37" plungers and is used in the 5020.

On most newer tractors, if Deere wants high power levels - they use in-line pumps instead. With your rotary pump - you've actually got one little pump making fuel for all the cylinders. With an in-line pump, there is actually a separate injection pump for each cylider - all riding on a little camshaft. That's why in-lines last much longer and can pump a lot more fuel.

Your pump turned up as far as possible and no parts changed - can make around 110-115 horsepower. I've never worked on a 4020 with a turbo - and never had turbo-version on a dyno. Maybe someone that has can tell you more.

The same basic pump on your 4020 is also used on many V-8 Ford and GM diesels. For marine use, pumps with four plungers are often swapped for large power increases - like the DM4 pumps.

As far a maintenance goes? First, your pump probably has a piece of plastic inside of it - and it will go bad no matter what you do. Usually lasts 10-15 years and will go bad from use and/or age. It can be upgraded to a newer part that never goes bad (EID retainer).

To protect metal parts - do NOT use pump low-sulfur diesel unless you put in an additive. Two-stroke engine oil works fine - mix at a 1 to 200 ratio.

The # on the pump is DM4629nt3147. I think the tractor was 110 hp from the factory and then it was turboed so I don't know what it would be making now but I think it is the newer style pump. Thanks for the info and I might do some tinkering

I guess I've got to start wearing my glasses. I thought you were asking about a 4020. The DM4629 pump has four pump-plungers - twice as many as the 4020 pumps. It is capable of pumping more fuel than your engine can use.