Start up issue

[KellerMAC]

I have a recently rebuilt 72 C10 and it sits during the week and on weekend when I go to start it, I have to pump the gas pedal and turn it over for about a minute before it finally starts up - I drive it through out the weekend and it starts on first turn. Then when I let it sit for the next week, it's hard to start and we go thru the same process again. I have a manual fuel pump on it. Is there anything I can do so it is ready to start after a week long layoff?

Thanks,

[geezer#99]

What carb?

[KellerMAC]

Rochester 4 barrel - factory carb - 350 engine - recently rebuilt carb and engine

[truckster]

Did you replace the filter in the carb inlet, and does it have the flowback preventer valve in it?

Also, did you set the float level according to the instructions in the rebuild kit?

[beadblaster]

Leaking fuel plugs on bottom of carb. Common problem.

[MARKDTN]

Originally Posted by beadblaster

Leaking fuel plugs on bottom of carb. Common problem.

agree

[Stocker]

Originally Posted by truckster

Did you replace the filter in the carb inlet, and does it have the flowback preventer valve in it?

Not to hijack.... My Q-jet acts similar to the OP's, the longer it sits, the more it needs to be cranked over before it will start. Carb has been rebuilt, leaking fuel plugs sealed, new mechanical fuel pump, newish filter at the carb's fuel inlet.

Maybe there's an issue with the flowback preventer valve and it would help if I knew what I was looking for. Any further info would be appreciated -- pic, diagram, etc. I have never heard of it before now.

[Toms67]

Is the Axcelerator pump working? When you pump it. Did you look in the carburetor and see if it was getting gas? With it not running.Sometimes they dry out. And when you get them wet again. it might work for a while.

[truckster]

Originally Posted by Stocker

Not to hijack.... My Q-jet acts similar to the OP's, the longer it sits, the more it needs to be cranked over before it will start. Carb has been rebuilt, leaking fuel plugs sealed, new mechanical fuel pump, newish filter at the carb's fuel inlet.

Maybe there's an issue with the flowback preventer valve and it would help if I knew what I was looking for. Any further info would be appreciated -- pic, diagram, etc. I have never heard of it before now.

It's a little black rubber piece on the end of the filter. Most paper filters have them.

[LSSierra]

Wow my 71 with a Q-Jet also does the same thing. Where is the best place to start troubleshooting?

[Stocker]

Originally Posted by truckster

It's a little black rubber piece on the end of the filter. Most paper filters have them.

Thanks! I'll make sure it's there... if not, I'll get a new filter and make sure it has that flap. I don't recall seeing it before, though....

[randy500]

Fuel pump is probably leaking fuel back to tank and has to refill line and carb, how old is the fuel pump.
You can check this by removing the line and seeing how much fuel is in it.
There is a check valve in the pump that when operating correct prevents drain back.

[geezer#99]

Is your divorced choke new too?
Did you clean out the crossover in the intake during the rebuild?

[demian5]

I believe this is just part of owning a carburated vehicle. We are all spoiled with fuel injection and all these bells and whistles. Yeah this is an issue that can be fixed, but its so common of carb vehicles that its almost like a theft deterrent!

[garyd1961]

You could install an electric fuel pump. It would pump fuel up to the carb before the motor turns over.

[Zogbert]

Had the same issue. Replaced the fuel pump, and that ended the problem.

[bandit0067]

I would bet the fuel plugs are leaking the bowls dry when sitting the short time. Then the fuel pump takes a bit to fill the bowls back up. If you want a quicker start, the bowl air vent tube, yes, that 1/4 inch "tube" that is slanted back towards the breathed stud, on top of the carb, you can squirt a few shots of fuel directly into the bowls. And then maybe a small squirt into front two barrels for a quicker fire up. I let too many of my old clunkers sit too long also.....