Fuel System: R2 carburetor

[jetboat]

I am having trouble with the gasket leaking on my R2 carb. replaced the accelerate pump and top gasket because I had a lag at high RPM. Fixed the problem I thought, now after about 200 miles it is starting again. Guessing the gasket is leaking by again .bought the kit from our vendors so should be the rite one. Any sealer needed? If so what type?

[64studeavanti]

IIRC, there are supposed to be 2 gaskets between the air horn and carb body.

[jetboat]

The gasket I question is the one under the top of the carburetor that you remove to replace the accelerate pump.

[skyway]

Warped castings?

[altair]

Sucking air in or leaking fuel out?

[jetboat]

No fuel leak anywhere, just has a hesitation like the accelerator pump is split. Is there any sealer that can be used on the gasket?

[StudeRich]

Sounds more like the High Speed Jet passages are clogged or other internal problems, Gasket Sealer is not needed and probably would not fix anything.

[jetboat]

It stopped doing it after I installed the pump and gasket, but after 200 miles it very slowly started again.now it is back to where I started.

[Mike]

According to the workshop manual, the R2 carb is supposed to have Permetex in specific areas of the gasket between the air horn and bowl, as well as a couple of the screws that hold them together. There are supposed to be two gaskets here. That would effectively raise the fuel level in the bowl, slightly enrichening all circuits. Or maybe they were just to improve the seal!
I don't know what that would have to do with hesitation. Are the distributor advance mechanisms clean and lubed?
Mike

[jetboat]

It acts like a accelerate pump when they dry out,so that is why I changed it and the top gasket.
and all was great like a say 200 miles or so then it very slowly started again ,now it's like it was before.
I will dig into the book with my carburetor guy and come with a plan . Thank you all.

[wcarroll@outrageous.net]

Assuming the R2 carb is essentially the same as any AFB, I would trust your instinct and remove the top hat to carb and operate throttle and see if you get good pump shot immediately, and that it’s not a dribble or delayed.

If either above, remove the pump and check for good fit in bore.

I have had aftermarket pumps that were poor fitting and poor performing and had to swap back to the original.

Some carb makes use a check ball valve to keep the pump primed that often goes missing or forgotten during rebuilds. One time I took a carb apart after a recent rebuild by someone else that was acting up and discovered they had dropped a second check ball valve atop the original not realizing it was already in the bore!

On modern AFB’s you can adjust the pump stroke which sometimes helps get the pump stroking in a better area of the bore. If there’s any way to adjust it you might do so and see if there’s any improvement.

I imagine the new pump has a rubber seal? I

I went through a few on a rebuild recently on a Willys trying to eliminate lag and ended up having to buy a special one said to have been made to fit properly.


Of course you could also have a clog in the discharge nozzle.

[jetboat]

Thank you, we will give it a through going over.