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Lou Van Anne
06-22-2015, 07:37 PM
64 R2 Hawk: Car runs fine until about 50 mph at which point the engine surges/hesitates and can't be driven on the highway. It has a new electronic distributor, recently tuned up, new correct fuel pump with an back up electrical fuel pump (used only after the car sets awhile). I just install a professionally rebuilt carburetor by a gentleman who has experience rebuilding the R2 AFB. When I turn on the electric fuel pump the issue goes away...but has a whine to it that would drive one crazy! Fuel filters have been change. What am I missing?...any ideas out there?

karterfred88
06-22-2015, 08:10 PM
Check the reference hose from the blower to the fuel pump top. May be the problem, or not. Sounds like not getting enough fuel or a vacuum leak (check your newly installed carb base gasket). Since it goes away with the electric pump, maybe the reference line isn't fooling the pump to put out more pressure, or the mechanical pump isn't keeping up and you're running out of fuel, leaning it out causing the surging. Maybe a bad new pump, or not an R2 style with the pressure reference. Doesn't seem to be an issue with supply from the tank, so I'd hone in on those two areas. Good luck.
Just a second thought--did you change the fuel hose from the frame to the fuel pump? Is your electric pump near the tank? It is possible there is a kink or a collapse inside of the fuel hose that opens up with the electric pump pressurizing the fuel hose at the frame to pump opening it up.

t walgamuth
06-23-2015, 05:29 AM
Sounds like running the fuel pump all the time would solve the problem. If its not mounted back by the tank, that's probably where you want it both for noise isolation and best performance.

SN-60
06-23-2015, 07:18 AM
As long as that new factory R2 fuel pump is working OK, I'd get that electric pump out of there.....It's really just an unnecessary complication anyway!

bezhawk
06-23-2015, 08:26 AM
Check for free movement of the metering rods, and the proper springs for your altitude. A bent rod or weak springs will also cause those symptoms.

rkapteyn
06-23-2015, 09:06 AM
Some of the R2 pumps offered are really Chrysler pumps and the arm needs to be bend just right to get a full stroke.

http://www.studebaker-info.org/tech/fuelpump/R2modfp/R2modFP.html

http://forum.studebakerdriversclub.com/showthread.php?579-Avanti-R1-fuel-pump-leaking-out-the-top-revisited

Robert Kapteyn

SScopelli
06-24-2015, 12:52 PM
If you have your electric pump in line with the mechanical pump, that is a big no-no.. the mechanical pump can not suck the fuel past the inner workings of the electric..

The mechanical pump was designed to draw on gravity feed.

Here is one way you can have both..

45106

PackardV8
06-24-2015, 06:11 PM
If you have your electric pump in line with the mechanical pump, that is a big no-no.. the mechanical pump can not suck the fuel past the inner workings of the electric..

FWIW, that's a yes, no, maybe. Some electric pumps will pass fuel to a mechanical pump with no restriction. Some won't.

jack vines

Lou Van Anne
06-25-2015, 10:01 AM
Seems to me that the problem is the mechanical pump...but it is brand new?(from SI)...I'm thinking maybe the boost reference line is damaged...can anyone explain to me exactly what it is supposed to be doing and how?...as I've never had a supercharged Studebaker before.

karterfred88
06-25-2015, 10:18 AM
Seems to me that the problem is the mechanical pump...but it is brand new?(from SI)...I'm thinking maybe the boost reference line is damaged...can anyone explain to me exactly what it is supposed to be doing and how?...as I've never had a supercharged Studebaker before.
Pressure from the Blower is transferred to the area above the diaphragm, changing the ambient pressure there so it puts out more pressure, or something like that. See the link for a more complicated explanation:
http://vs57.y-block.info/fuelpump.htm
But I still think it's either your pump or fuel hose coming in--take it off and replace it with 3/8 fuel injection hose-cheap and easy and won't hurt even if it's not the problem. Although sticking metering rods could cause the symptom, it goes away with the electric pump assist, indicating fuel starvation, as that won't make the rods in the carb move any better. At 50 MPH you're not getting much boost anyway, I think it's a fuel flow problem on the mechanical side. Just for fun, bypass the electric pump completely with a piece of the 3/8 fuel injection hose. See if it goes away, check valve in the electric pump could be getting in the way of normal fuel flow--again cheap and easy.

Mike Van Veghten
06-25-2015, 10:37 AM
Having an electric pump feed a mechanical pump is a bomb waiting for a chance....very unsafe. I don't care how long someone's "done it this way"...it's still a danger.
All it takes is a leak in the diaphram, and fuel will be pumped into the oil pan..!

If you want the mechanical pump for visual reasons...hollow the mechanical pump and just run a fuel line "thru" it.

Electric pumps ARE out there that are VERY quiet..! The Carter inline on my Lark is hardly audible, even with the engine not running.

Mike

TWChamp
06-26-2015, 10:10 AM
Good thoughts from Mike. I have a precision brand 6 volt electric pump that I bought from O'Rielly's for $52, and I have two Holley 12 volt pumps that I bought for $5 each at a swap meet. All three are rotory vane pumps and you can't here a thing inside the car, even with the engine off. Be sure to ask for a rotory vane pump and not a pulse or diaphram electric pump.

In the late 70's I went through about 5 or 6 AC pulse pumps in my Renault R12 GTL before I finally sold the car. I'm sure the main problem was the corn crap in the gas eating up the bellows, but they were also noisey. The rotory vane pumps I have now don't have any rubber parts to be destroyed by the corn crap gas we sometimes are forced to buy while on a trip away from home.

BTW, I use a resistor to drop the voltage to 3 volts on my Holley pumps, and they now have the correct flow and pressure. Without the resistor the 12 volt Holley will put out 14 pounds of pressure even when running it on only 6 volts.

Lou Van Anne
06-29-2015, 01:41 PM
PROBLEM SOLVED!...bypassed the electric fuel pump and she now runs fine with just the mechanical pump. Thanks everybody for your suggestions.

jgrohs
06-29-2015, 10:32 PM
glad that took care of it!

karterfred88
06-30-2015, 05:54 PM
PROBLEM SOLVED!...bypassed the electric fuel pump and she now runs fine with just the mechanical pump. Thanks everybody for your suggestions.
Great! I thought it was the fuel flow, that's why I suggested bypassing the electric pump completely in post #10. Glad it worked.