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Author Topic:   BG diaphram bypass help
posted March 23, 2004 02:57 PM
IM running the diaphram bypass with a mechanical fuel pump,the bypass is the one with out the idle bleed jet. No matter what I do I can only get about 6 pounds of fuel pressure I run a 11# pro cam pump.

I have the bypass mounted onto my fuel log on the back fitting,like the instructions say.
has anyone else had this problem?

posted March 23, 2004 08:08 PM
steve could probably answer this better than i can as i'm not too familiar with this type of BG fuel system.
i would take a guess and say that your fuel pump can't deliver any more pressure. if it is a mechanical pump (as in stock location lever action) it is quite likely unless it is a BG race pump or similar.
if it is a rotary pump (belt drive, cam drive ect)in good condition then you have another problem.

[This message has been edited by rocket36 (edited March 23, 2004).]

posted March 24, 2004 04:20 PM
Perhaps it is your Gauge, After replacing my BG pump because it was only going to 6 pounds, my new BG 15lb pump also would only pump 6 pounds. Replaced the gauge and now I have two good pumps.

posted March 26, 2004 03:51 PM
I was thinking the gauge also.Its a new longacre gauge panel but when we ran all our gauge lines to our gauges somehow the oil pressure line was hooked up to fuel pressure and fuel to oil pressure,needless to say we had all kinds of fuel pressure when we were priming the engine,wasnt for sure if that would have coused the problem or not.

posted March 27, 2004 10:05 PM
If you are running methanol, you should not need the regulator and the way pro cam works it will only make 11lbs max if it is a #11. And for a methanol motor the rule of thumb I learned was 9 to 11 lbs of fuel pressure at the carb. If you are on gas 6 to 9 ibs of fuel pressure. Just judgeing by your post that may be your bypass is too big. The bypass is to set your idle pressure (3 to 4 lbs at idle) the diaphram spring is for top end fuel pressure.

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