Rochester 2 GC problem

[stevef]

Wonder if anyone has experience with the Rochester 2 GC 2 bbl. carb?
I have a 7045162 on a 75 Pontiac 350 (M) that's giving me problems. I've had the car for 9 years, and it used to be fine, but now it's gotten to be a real problem. It starts easily when cold. But, when I go somewhere, park, and come back out, it's very hard to re-start. I think the bowl is leaking into the intake and flooding. Whatever causes it, it is flooded.
I put a kit in it, but it still does it.
I was trying to think of where the bowl could leak. It has a power valve in the middle of the floor of the bowl. It's a brass valve with a small pin in the middle which is pushed by a spring loaded rod hanging above it that is vacuumed actuated.  There is also a mechanical power valve at the bottom of the accelerator pump well, which has a button that is pushed by the bottom end of the pump. The valves have base gaskets. I'm wondering if there are any seals inside the valves that could deteriorate and leak. Or are they just small spring loaded pistons with no interior seals? So I don't know if they should be a concern. They don't look like they come apart, and I don't see replacements for sale.
Also, there's a small aluminum check valve ball in the bottom of the pump well. The one that came out of the carb is larger than the new one in the kit. I bought 2 kits, and both have the smaller alumninum ball. I put the new one in, but now I'm thinking I should put the old larger one back in, since maybe the small ball isn't sealing?
I've adjusted the float to specs. It was off a bit. I'm getting a new float in case the old float got saturated.
There's also a hesitation when taking off. I can feather the takeoff and once it's going it's fine and power is good. But if I accelerate from a stop too quickly, it can die. I think it's not getting a sufficient pump shot. If the check ball is not sealing, that could be the problem.
It's a simple carb, and should be easy, but getting the right parts for it has been hard.
Sorry for the long winded post. Any ideas would be appreciated.

[Cliff Ruggles]

Pressure test the bottom plugs in the casting just like we show for the Q-jet.  Install screw in plugs if you find any leaks.  We have a plug kit for them off the website, just specificy 2GC when you call the order in.

BIG problems currently with 2GC accellerator pumps found in over the counter kits.  We just finished tested the latest upgraded version for the manufacturer, and have them available for sale.

The aluminum check ball MUST be seating off effectively or there will be a BIG delay in fuel delivery from the accellerator pump.

If you are going to use the aluminum check ball, you may need to use a small steel ball to form a new seat.

I don't use them for 2GC units built here, we block off that passage as they are a trouble area for those units......Cliff

[stevef]

Thanks alot for your thoughts about it Cliff! It looks like I figured it out.

I used a NAPA kit first and it has a blue pump, which looks like better cup material. But the kit had some wrong parts in it. The power valve gaskets were the wrong size and the aluminum check ball was smaller than what came out of my carb. Even the mounting gasket was wrong, and couldn't be used on my car(didn't cover the entire hole on my EGR intake). It claimed to be for my carb number, but not quite as it turns out.

Trying to use the smaller ball must have been my stumbling problem on takeoff, since it probably didn't seat well enough. I bought another carb kit by Walker and it had all the right parts....correct sized power valve gaskets and the larger size aluminum check ball like I originally had. And correct mounting gasket. I also bought a new float. So I rebuilt it again today, keeping the better looking NAPA pump. It's working great now. Easy starting, no flooding, and no hesitation on takeoff. It feels good to have it working like new again   .

[Cliff Ruggles]

"I used a NAPA kit first and it has a blue pump, which looks like better cup material."

Don't be fooled by "blue" seals, most are too "soft" and will swell up and fail in contact with ethanol.

The new pumps we tested have a much better "blue" seal, just like our q-jet pumps, with a garter spring under it to keep it against the pump bore.

We also eliminated the check ball when we did the testing for them, and the pump works perfectly.  The check ball is just another thing to fail and cause pump delivery issues, very common problem with those carburetors........Cliff

[stevef]

Good to know. Thanks!