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Holley 750dp, no fuel going into front bowl??

19K views 16 replies 5 participants last post by  brian oneil 
#1 · (Edited)
Hi, I have a Sean Murphy Induction 750dp, I was driving the other day and thought I ran out of gas but came to find out that I was not out of gas, but my front (forgive me I dont know the exact nominclature for these parts) fuel injector is not spraying fuel into the manifold. I have tryed to manually press the lever that actuates the injector and nothing comes out(at first there was a small mist, then fumes, then nothing at all). I am assuming that no fuel is getting to the front bowl. I am getting pleanty to the secondaties and they are working just fine. I also made sure I am getting fuel from the pump. My fuel line from the pump to the carb is a cheepie and has a small pressure gauge on it, just so yalll know. I would apreciate all and any info that I can get from the experts! Thanks in advance:beers:

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#2 ·
So....if i am reading this correctly, there is fuel going into the back bowls, but not the front? Have you checked the front line to see if it has a block? Pull that puppy off and blow it out with air. Start there and see what that does.

What kind of pump do you have? Whats the PSI read when the car is running?
 
#4 ·
thanks guys, Im running what apears to be a stock pump. Was on it when I got the car. And psi was always jumping arround on me, I think the guage was broken because it was always bouncing between numbers and now the guage face is completelly fogged up. I did pull the rubber line off the chrome line that goes to the guage then to the carb, and turned the enging over a few times to see if the pump was good....it was, and gas was flowing out of the hose. So I think it would be a problem after the fuel pump.
 
#5 ·
You could have a piece of trash in the needle and seat or an improperly adjusted front float. Removed the sight plug on the side of the fuel bowl and see if you see gasoline in the front bolwl. It should be even with the bottom of the inspection port. As gas enters the bowl it will slosh around and spill out the side.

Big Dave
 
#6 ·
I checked the needle and seat, no blockage. I have been trying to remove the fuel line inlet from the front bowl but it is on there like no bodys buisness and Im startign to mess up the nut on the carb side, is there some trick IM not getting? thanks guys, Im kinda rookie
 
#9 ·
I checked the needle and seat, no blockage. I have been trying to remove the fuel line inlet from the front bowl but it is on there like no bodys buisness and Im startign to mess up the nut on the carb side, is there some trick IM not getting? thanks guys, Im kinda rookie
Checked the side inspection port, no gas in the bowl at all. Must be blocked in the line? Is there a filter at the inlet of the carb that could be clogged?
The fuel bowl inverted flair inlet has a one inch hex nut and requires a six point socket or a strong open end wrench that will not distort. The inlet can but generally doesn’t have a fuel filter behind the inlet. The inlet is a steel part that threads into the soft pot metal of the fuel bowl (pot metal is zinc alloyed with lead and tin, so it is softer and heavier than aluminum used not for it strength but for it’s low melting point which makes it easy to cast parts with it). Because the steel is a dissimilar metal it needs to have antiseize on the threads to keep the inlet from chemically welding to the metal of the fuel bowl. And because the steel 7/8–20 threads are much harder than the soft metal of the fuel bowl you must use extreme care to keep from cross threading it as it will cut new threads before you are sure it is threading in correctly unless started by hand with light finger pressure.

http://www.holley.com/26-26.asp

The chromed 3/8 fuel feed line tubing nuts needs to be removed with tubing wrenches to keep the soft brass from rounding or distorting out of shape (once it bends it is useless as it will never seal again).

Big Dave
 
#12 ·
I like the pictures! Very detailed!

I think you say it right, just man up and get it done, with the right wrenches. People tend to overtighten the fuel lines, as I am guilty of that myself. There might be a mesh screen in the inlet which could be clogged. If everything is good inside the carb, and there is fuel to the feed line...
 
#14 ·
Well....now somehow i got it to shoot gas again for me. Must have been some thing that unclogged while I was checking the float needle and the lines. But now that she's running again, I have fuel leaking (alot!) from the line inlet. I never even took the line off the carb so I dont know why it would leak. Any help? thanks!
 
#15 ·
Well....now somehow i got it to shoot gas again for me. Must have been some thing that unclogged while I was checking the float needle and the lines. But now that she's running again, I have fuel leaking (alot!) from the line inlet. I never even took the line off the carb so I dont know why it would leak. Any help? thanks!
As I mentioned above the nuts on the fuel line are made of chromed brass which is very soft. It bends out of shape easily, but is next to impossible to bend back into shape so by attempting to take the nut off with an open end wrench it deforms the fitting allowing gasoline (which is very viscous) to leak past the threads.

Correct tools are important for some jobs. When playing with soft brass and alumium compression nuts you need a tubing wrench.

Big Dave
 
#16 ·
Thanks Dave, the advice is always welcome! I was using a flare end wrench, probablly not just the right tool but the best I had. I better just leave this fix to the pros at the carb shop down the road
 
#17 ·
You dont need to so that. You can buy a replacement dual feed fuel line at most auto parts stores or order one from your favorite parts house. If you take it to a car shop that what they will do, replace it (if the fuel line is bad) and charge you an arm and a leg in the process. Save yourself a whole lot of money and swap it out yourself :thumbsup:.
 
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