MD injection pump differences

I recently bought a farmall md that was stuck, both injection pump and motor. Swapped the motor out with a free one in good shape, just got another injection pump that worked when it was taken off a running tractor at the scrap yard. The old pump has an "A" on the side cover and the new one has the same cover, without an A. When people refer to the A pump vs. the B pump, does the B pump have a letter or is it refered to as the B because it doesnt have an A? Sounds like a stupid question but after poking around nobody has been able to answer it.

the new pump the number 65309DA and the old one has number 65306DA on the tag if that means anything.

Lowest number is a MD, 6 series and the other is a WD9 pump. Both are pre B pump. B pumps if fitted to those tractors has a drip tube or drip tube opening in the pump bottom. Also just a primary pump on rear of injection pump with 2 line hook up to it instead of 3.

There were 3 IH pumps used on the gas start tractors (There is also the Bosch pump). This is the way that my pump rebuilder (now deceased) explained it to me and his informatin does match what I have in my W-series collection. The earlier tractors had the "pre-A" pumps which had no marking. The later tractors had the "A" pumps which are identified by the large "A" on the pump. Finally, the "B" pumps which were identified by a large IH symbol on the upper part of the pump and yes, the "B's" had the drain tube at the bottom. IH started installing the "B" pumps part way through the production of the Supers, the regular tractors never came from the factory with "B" pumps.

(quoted from post at 19:51:03 01/01/12) Lowest number is a MD, 6 series and the other is a WD9 pump. Both are pre B pump. B pumps if fitted to those tractors has a drip tube or drip tube opening in the pump bottom. Also just a primary pump on rear of injection pump with 2 line hook up to it instead of 3.

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Is it true the WD-9 pump can be run on a 6 series tractor with a couple adjustments?

I have read on websites that a WD-9 pump can be put on a 6 series tractor with adjustments. I have never actually tried it so I am not much help on that. You might want to put a post on the Red Power website and someone will likely have a better answer.

(quoted from post at 11:05:11 01/02/12) I have read on websites that a WD-9 pump can be put on a 6 series tractor with adjustments. I have never actually tried it so I am not much help on that. You might want to put a post on the Red Power website and someone will likely have a better answer.

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The only real difference between a 306 and 309 pump (or a 314) is the plunger cut. The actual plunger is interchangeable between nearly all of those pumps (except for being match ground). IH made adjustments to each for different RPM settings and stuff like that so you will see different springs in use. Yes they will basically swap.

(quoted from post at 12:13:29 01/03/12)

(quoted from post at 11:05:11 01/02/12) I have read on websites that a WD-9 pump can be put on a 6 series tractor with adjustments. I have never actually tried it so I am not much help on that. You might want to put a post on the Red Power website and someone will likely have a better answer.

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The only real difference between a 306 and 309 pump (or a 314) is the plunger cut. The actual plunger is interchangeable between nearly all of those pumps (except for being match ground). IH made adjustments to each for different RPM settings and stuff like that so you will see different springs in use. Yes they will basically swap.

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It was probably you that said it over on RPM. So could I run a 9 pump on the MD to take the place of turning the pump up?

(quoted from post at 18:50:23 01/03/12)

(quoted from post at 12:13:29 01/03/12)

(quoted from post at 11:05:11 01/02/12) I have read on websites that a WD-9 pump can be put on a 6 series tractor with adjustments. I have never actually tried it so I am not much help on that. You might want to put a post on the Red Power website and someone will likely have a better answer.

Click to expand...

The only real difference between a 306 and 309 pump (or a 314) is the plunger cut. The actual plunger is interchangeable between nearly all of those pumps (except for being match ground). IH made adjustments to each for different RPM settings and stuff like that so you will see different springs in use. Yes they will basically swap.

Click to expand...

It was probably you that said it over on RPM. So could I run a 9 pump on the MD to take the place of turning the pump up?

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In theory yes, but I haven't done that one yet. The basic 6 plunger will still produce considerable fuel at full on. (I think the numbers are 55cc vs 75cc but I don't have the book handy.) The better advantage is that the 9 pump will deliver fuel quicker and should give better response at low RPM. Again, haven't tried it.