I have a 72 360 Dodge engine with a Holley two barrel carb,stock Holley from the factory. Problem:After car sets overnight engine wont start without priming it first.Once it starts, it will start all day fine.I have rebuilt the carb, new accelerator pump rubber and complete rebuild.Thats not to say I rebuilt it correctly, but I think I did.It has to be bleeding off the gas some how? Also motor has a new fuel pump on it. Any help you can give me on this would be great, I thought for sure it was the accelerator pump, but apparently not. Thanks in advance.
I don't know diddly about the carb you talk about, but for the sake of conversation I will assume it's not too far different from other Holley's I have worked on. FIRST and foremost - when it sits overnight - pop the aircleaner and push the linkage - can you see the fuel squirt into the venturi??? A two barrel means you ought to have a discharge nozzle with 2 separate discharge outlet points - meaning you should IMMEDIATELY see TWO STREAMS of fuel shoot out. If you don't then you accelerator pump system may STILL not be functioning properly. The accelerator system usually consists of some sort of fuel well and a 1 way valve to let fuel in an dnot get squeezed back out when you push in the diaphram. On some holleys there is also a check valve (near the discharge nozzle - on top) to keep the passage way full - so that fuel is there for a near instantaneous squirt. The pasage ways between them are small and easily plugged - manually depressing the linkage and or accelerator pump arm will allow you to check that it is functioning. Also keep in mind if the acceleartor pump well is leaking you might find a similar type problem - this goes for the main fuel well also!!!! Let us know!!
This may seem like a dumb question but is the choke closing? I worked on a lot of these when they were new and the choke plate would stick in the bore but only when they were cold. Once they warmed up they were OK. Filing the choke plate for a little extra clearance fixed it. Sometimes they wouldn't stick off the car but would when bolted on. Seems like some of these also used a fuel pump with a return line to the tank. I've seen where the wrong pump was installed and the return line plugged cause problems too.
I have a three of these carbs on three different 360 motors. At the bottom of the fuel bowl there are "plugs" that Holley put in to close off the end of the passages when they drilled the path ways for the fuel to travel through the carb. I have seen where these passage plugs leak fuel. Often times you can see the fuel leak stain, I've never actually seen them leak fuel, probably too slow, but I think they may only leak at a very specific temprature. To see the plugs, you have to remove the carb, and remove the throdle plate section. I will look tomorrow and see if I have one of these carbs apart and take a picture of the plugs. When they leak, the fuel runs into the intake manifold. I'd bet if you shut off the motor for about 10 minutes you have to press the peddel to the floor for the motor to restart? This is an inducation of the passages leaking. When it sits for 10 minutes, the fuel sits in the intake and actually floods the motor for a short peroid of time. When the motor sits over night, the gas in the intake evorperates, but you have to crank the motor long enough to refill the carb. A two part epoxy over the plugs usually seals them, but I put an electric fuel pump on all my old Dodges, solves this and a few other issues. Gene
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