WALBRO Pump for Carbureted System??

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My problem is when it's cold it will read say 8lbs. After it warms up
Tbe PSI will drop off a lot. Like in the 4 psi range. I'm starting to think
I might have a bad regulator. After adding a restrictor in the return line I
thought I had it taken care if but it's not. I will
Swap out the gauge and see if that helps. I will do one change at a time
Until I find tbe problem.
 
Mad Dart said:
I am running the Walbro GSL-392 pump with the FPR mounted on the inner fender as usual and set up like yours use to be using -8 feed and -8 return. I was having issues too where the FP will be high and after the car warms up it would drop a bit. I have been chasing my tail on it like you did. Recently I put a restrictor in the return line and that seemed to help but then again after it was running a while and got hot it returned back to the same issue, not as bad but still there. When I get back out in the garage I will be setting it up just like yours is.

Did your FP start high and drop or did it do the opposite and spike? What exactly was your issue with the FP?

I also heard that Liquid filled gauges can sometimes give a false reading when they get hot? Have you heard this before? Do you run a liquid filled or just a regular? Any input on the subject will be appreciated.
Click to expand...
I am trying to get a good system also with a 392 pump and doing some research.Louis I have heard from many folks you will never get a steady reading from a liquid filled gauge after it warms up and I am hooking mine up the same as you but now im starting to wonder about doing it different. what regulator are you using Louis?
 
I just did a search and there are tons of guys having the same problem as me wit the liquid filled gauges under the hood. Heat screws up the reading causing the gauge to read low psi. In turn like myself I turn the FP up after it gets hot back to say 7pSI but it is actually about 11 and at that point the needle and seat can't hold the pressure and the carb overflows flooding the motor. This guys scenario mimimicks mine to the T

Every 30* in temp it will loose about 1lb PSI on the gauge. POS

http://www.firstcoastcobraclub.com/viewtopic.php?f=8&t=1009
 
I'm using this regulator and have had no issues..................

http://www.summitracing.com/parts/pfs-10653/overview/
(3 in/out ports, 1 return port, gauge port)

but I know a couple guys who have tried this one as a cheaper alternative with good results.

http://www.summitracing.com/parts/mrg-2015/overview/
(2 in/out ports, 1 return port)


The only thing is that it doesn't have a gauge port, but a simple 3/8" to 1/8" npt reducer would allow a screw-in gauge to be installed.

http://www.summitracing.com/parts/fra-491203-bl/overview/
 
UOP said:
I'm using this regulator and have had no issues..................

http://www.summitracing.com/parts/pfs-10653/overview/
(3 in/out ports, 1 return port, gauge port)

but I know a couple guys who have tried this one as a cheaper alternative with good results.

http://www.summitracing.com/parts/mrg-2015/overview/
(2 in/out ports, 1 return port)


The only thing is that it doesn't have a gauge port, but a simple 3/8" to 1/8" npt reducer would allow a screw-in gauge to be installed.

http://www.summitracing.com/parts/fra-491203-bl/overview/
Click to expand...









http://www.summitracing.com/parts/mrg-2015/overview/ The cheaper, Mr. Gasket regulator doesn't seeem to be boost-referenced, either... am I reading that right?

If so, that would disqualify it from being used as a forced-induction application, right?

Just want to be sure I'm right about that.
 
You can test the error of the liquid-filled gage at temperature by turning the car off and seeing the "zero reading". You may have to vent a hose to get true 0 psig, depending on the pressure regulating system you use. Even if it does have a major temperature drift, use it while cold to set your regulated pressure, then don't worry about the reading when warm. The regulator should hold the setpoint.
 
Thought I would update what happened to mine. I had 2 issues but they have both been resolved.

1) First issue was the Liquid Filled Gauge
2) Second Issue was the Rear Float was filled with fuel

I changed out the floats & needle and seats on both bowls & Jet extensions at the same time.

Both issues have been fixed. FP is ROCK STEADY at 6.5 PSI using 1/2" Feed and 1/2" Return lines with the Walbro GSL-392. I did not move my PF regulator. It is in the original location.
I am using a Mallory 4307M Regulator that is Boost Ready.

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View attachment phpRHySQwPM.jpg
 
give this thread a bump for my reference..

trying to put together my fuel system for a carb'd 530HP engine. I have to use electric fuel pump, (walbro gsl392) mounted near tank, with possible 3/8 feed and 3/8" return..but after reading maybe I should use a larger return? at what point is a larger return needed?
 
mopardude318 said:
give this thread a bump for my reference..

trying to put together my fuel system for a carb'd 530HP engine. I have to use electric fuel pump, (walbro gsl392) mounted near tank, with possible 3/8 feed and 3/8" return..but after reading maybe I should use a larger return? at what point is a larger return needed?
Click to expand...

James, I believe you will be fine with how you have it. I have seen guys with multiple 392's use a larger feed and return, single 392 you will be fine. The regulator will do its job for you with what you got.
 
James,

Any restriction in the return line may cause regulator creep (increases in pressure).

The size of the return is more about the size of your pump. If you are pushing a lot of GPH, the return needs to be larger than the feed. Most of the time with a 140-160gph pump, same size feed/return usually works well.
 
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