Starting problem with 64 283 in El Camino. If the engine has not been running for 12 hours or so it takes up to 20 seconds or so to get started. If fuel is poured directly in carb or starting fluid is used she starts right up. Carb is quadrajet freshly rebuilt. Had same problem when carb was new. Have changed fuel pump, no fix. Any ideas what to test or check? No leaks obvious in fuel line from tank. :confused:

Almost sounds like the fuel is draining back down from the car like the check valve in the fuel pump is bad. I would either replace the fuel pump as you might have gotten a bad one or install an inline one way check vavle to prevent fuel from flowing back down the lines.

I had a similar problem with my chevy pick-up with a Q-jet and a 454. It could be the porous casting material in the carb itself allowing fuel to seep out of the bowls and into the manifold where it evaporates. If you have another carb laying around, swap it out and see if the problems follows or clears up.

http://www.carcraft.com/carcraft/howto/p123761_image_large.jpg

You need to epoxy the plugs at the bottom of the fuel bowl. These will leak and drain the fuel bowl after setting for a few hours.

Epoxy the plugs as shown in the previous post & replace the carb fuel filter with one that has a built in check valve. Make sure you have a spring behind the filter to seat it up against the inlet fitting/nut. Are you sure your accelerator pump is functioning properly?

I run all my q-jets with no carb filter and haven't had any problems with fuel leaving the bowl after shutoff.

TY Guys. Will try all suggestions starting with epoxying the plugs.
Will post results.

I had the exact same problem with a quadrajet on my '64 El Camino. I had rebuilt the carburetor before installing it, never had a problem with a quadrajet like this before. In addition, it would run out of fuel when I romped on the thing. The fuel pump just wouldn't suck enough fuel through the 5/16 fuel line from the tank fast enough to keep the small fuel bowl in the quadrajet full.
I've never really liked Holley carburetors much, but it was either install a Holley or replace the fuel line from the tank. I went the Holley route, it starts after sitting for months and runs like a raped ape.

Looks like onovakind67 nailed it to me. I made a living with that fix back in my dealership days. Nice graphics too!
graemlins/hurray.gif

Mark

I had the same starting problem with 2 different Rochester carbs. Last carb had the plugs epoxyed. Finally replaced the fuel pump with a new Delco. Now it starts right up everytime.

Well first I replaced fuel pump, not any help.
Epoxied fuel bowls and put in fuel filter with check valve. Now it starts much quicker but still not as well as it does after only sitting for a short time(under 12 hours). Still takes five seconds of cranking and 10 pumps or so on gas pedal to get gas to manifold and engine. After cranking for five seconds no fire what so ever. Then starts right up immediately.

By the way THANK YOU VERY MUCH

Solved just this very problem just last week.

In my case the carb was getting too hot. The fuel evaporated. I installed the GM heat shield AND the thick base gasket with the plastic inserts in the bolt holes. Now it starts first time every time, within 5 seconds! That's with one pump of the accelerator pedal.

If I had every Qj that had the plugs epoxied, but wasn't actually a leaker, I think I would have a stack from here to the moon! :D Sure, some leak, but generally the older ones are more likely to have this problem.

Like onovakind 67 pointed out, the anti-drainback valve might not fix it. In fact, it may be part of the problem. The anti drainback valve was used with slightly higher pressure fuel pumps. Install it in a system using the old, lower pressure pump and it may give you a starting problem.

Mike