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2R2
07-04-2008, 07:11 PM
Lookng in the parts book, the accelerator pump for an R2 carb carries a unique part number. Can anyone tell me what is unique about it?

Here's my problem - I installed my rebuilt R2 carb, and under blower pressure, fuel was pushed out the top of the accelerator pump, past the seal the unique R2 carbs have. SO, I order one of the new, brass seals with the captured "O" ring, and in adjusting the carb, I can not get enough stroke with the pump. It is supposed to be 29/64", from the top of the carb to the top of the pump, and the most I can get is 25/64", unless I have the pump come up past the seal. I never bothered to measure it with the original seal. Hope this makes sense, I know my explanation may not be to clear!:)

Anyone else ever have this problem with an R2 Carb (3725S)[?]

Eric DeRosa

'49 2R-5 (original Survivor)
'63 R2 Lark (barely surviving)

53k
07-04-2008, 08:01 PM
quote:Originally posted by 2R2

Lookng in the parts book, the accelerator pump for an R2 carb carries a unique part number. Can anyone tell me what is unique about it?
Here's my problem - I installed my rebuilt R2 carb, and under blower pressure, fuel was pushed out the top of the accelerator pump, past the seal the unique R2 carbs have. SO, I order one of the new, brass seals with the captured "O" ring, and in adjusting the carb, I can not get enough stroke with the pump. It is supposed to be 29/64", from the top of the carb to the top of the pump, and the most I can get is 25/64", unless I have the pump come up past the seal. I never bothered to measure it with the original seal. Hope this makes sense, I know my explanation may not be to clear!:)
Anyone else ever have this problem with an R2 Carb (3725S)[?]

Some years ago I rebuilt my R-2 carb with a kit from a Avanti vendor (no longer selling) and I found that the accelerator pump was the wrong one for an R-2 (too short). Maybe some of the kits are still out there.


[img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/R-4.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64L.JPG[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/64P.jpg[/img=right][img=right]http://www.frontiernet.net/~thejohnsons/Forum%20signature%20pix/53K.jpg[/img=right]Paul Johnson, Wild and Wonderful West Virginia
'53 Commander Starliner (since 1966)
'64 Daytona Wagonaire (original owner)
'64 Daytona Convertible (2006)
Museum R-4 engine
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1972 Gravely Model 430 (Studebaker name plate, Studebaker Onan engine)

JDP
07-04-2008, 08:19 PM
Did you try adjusting the stroke ? As I recall moving the link up allows the pump to come up further.

JDP/Maryland
"I'm a great believer in luck and I find the harder I work, the more I have of it."

Thomas Jeffereson

bige
07-04-2008, 08:33 PM
I'm trying to grasp the "up past the seal part", I can't picture what you mean?

I do remember on my 3725S having difficulty with the diameter of the pump shaft and the seal. When I replaced the original seal and used the kit pump it would stick. I think my solution at the time was to swap the old leather for the new neoprene and re-use the original pump.



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