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Discussion Starter #1
engine is a freshly rebuilt 396 that im trying to do the breakin on, it has a holley 750,summit fuel line with guage, and holley pump(all new). when i dump gas directly into the carb it will start for just a few seconds then die as soon as fuels gone. after checking all the lines(tank to pump,pump to carb) they all seem to be free of any obstructions as air blows thru them. but when i disconnect them no fuel leaks out and the hard line from summit seems to have no gas in it. any ideas as to why im not getting gas to the carb?? thanks
 

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Is fuel getting to the fuel pump inlet?
If so, is the fuel pump pushrod seated correctly on the fuel pump lever? If all this checks out ok, the fuel pump may be
faulty. If no fuel is getting to the fuel
pump, remove gas cap and see if fuel begins to flow to fuel pump. Just a few things to check.......
 

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you didnt say what model holley pump... electric or mechanical?
 

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Discussion Starter #4
the carb is a holley mechanical, when i disconnect the lines there is no gas coming out at all and i dont have a gas cap on either. theres only about 4-5 gallons of gas in the tank, could that be the problem? i talked to a few people and they say the pump might just need to be primed and to keep trying but im worried about hurting the motor when i continuely try to start it. also someone told me to take a air compressor and force air into the tank and that might force the gas up the line?? any other thoughts??
 

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If you have a vaccum gage, put it on the suction side of the pump and check it.
I can't remember if I ever heard what a good number is, but I would guess you would want 8 or 10 inches of vaccum.

If you have vaccum, then there is probably an air leak on the suction side of the pump, between the pump and tank. The pump would rather pump air than fuel. The slightest air leak into the line will stop it from pumping fuel.

If no vaccum check the outlet for blockage to the carb or stuck or mis set needle and seat.
David
 

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Hmmm, this is a nasty one. I hope you don't end up with an engine full of flat cam lobes before you fix it!! 3-4 gals. is plenty, it should have gas. This is a little extreme, but if you put a long hose on the steel line (from the tank) at the pump and suck on it, do you get a mouth-full? If you do, take off the pump. Check the pushrod. You did install the pump pushrod, right? If you clamp the pump in a vise, and work the lever with a finger over the suction side, you should feel the suction. You can even put a hose in a container full of liquid and actually see it move fluid if you want. You didn't cross the fuel lines, did you? Make damn sure this is fixed before starting it again!! Proper cam breakin is critical!! The engine must run at around 2000 rpm for 30 minutes!! Don't even think about trying to start it again until you KNOW this problem is fixed.
 

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if i am right there is no one on this board who can answer it better than me. i dont know the holley but if it is "knock-off" of the edelbrock series mech pumps here is your answer. the arm that goes against the fuel push rod is composed of a "laminate" of thin steel plates. you will see that the part of the pump arm against the diaphragm however narrows down to one small piece of metal. this is broken. if you reorder the same pump it will continue to break. do yourself a favor if you need a high volume mech pump use the carter race pump. it is about $50 and has a stamped one piece steel arm and will last much longer. i took my 2nd broken pump of this year (edelbrock) to summit in sparks (reno) last saturday. of course, the guy there had never heard of any problems before.... yah right. anyway, the carter is a stronger piece it just doesnt look as nifty.
 

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Make sure the push rod is the proper length for your application. I mixed mine up before and had a similar problem. The rod was too short for my pump so the result was no pressure. I was also using a Holley pump.

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67 SS
70 Z/28
 
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