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I recently rebuild a Rochester B. I put everything in carefully. The last thing that I did was check and adjust the float settings to the specs.

It ran great for about 10 miles. Now it floods, won't start and seaps gas where the throttle body meets the insulator. I'm assuming that the bowl is just flooding and that is why its coming through the insulator.

I've had it apart a couple of times but everything seems OK. Does anyone have any ideas of what I should check?

Thanks,
Mark

MarkT,

I would look at the needle and seat. Could some debris (teflon tape?) have entered the carburetor and either wedged itself in the seat, or damaged the little viton tip of the needle.

Did you "float the float"? No holes allowed!

Make sure the float isn't hanging on some internal structure. If this is a cause and effect kind of deal, your rebuild is the culprit.


Stuart

One problem - the kit that I purchased didn't have the correct replacement needle or seat. The last time that I took it apart I noticed the needle was sticking a little. I thought I fixed it though when I put it back together.

I didn't think about floating the float - Good call. I'll check that.

I've had this thing off so many times in the past few days in minutes flat. I feel like I'm on a pit crew.

Mark

Mark,

The plot thickens!


Stuart

Stuart

Stay tuned.............

Mark

You did remember the gaskets between the insulator and carb? The insulator and the manifold? I ask because that was something I forgot to do. Oops.

The throttle body gasket that came with the kit from Classic Parts is a lot thinner than the one that I originally had on it.

Are these better? I'm not sure if I should stick with my original rubber gasket?

Sometimes the float sticks to. If you take a screwdriver and tap the carb with the blunt end you can jar it loose.

My carb was flooding at 1 point cause of crap that kept getting into it. Definatly check that out again. Blow out all the passages.

I can put mine back together blind folded, I had it apart about 10 times!

I made my own gasket cause the replacement was thinner. And if you overtighten it will leak gas like crazy, I would think it was better to use a thicker gasket.

Good luck, Jeff

When a carb floods it has to be getting by the needle & seat. The usual cause is foriegn matter get in although some of the things mentioned are good possibilities. You should have a filter right where the gas enters the carb.

Some causes of carburetor flooding:

Possible carburetor problems
(A) defective fuel valve
(B) dirty fuel
(C) failure to flush fuel line after disconnection
(D) defective float
(E) cracked casting
(F) improper float adjustment
(G) incorrect fuel valve orifice
(H) defective accelerator pump discharge check valve

Other possible causes
(A) fuel pump creating excessive pressure
(B) wrong gas tank cap (no joke)

There are probably others, but one (or more) of the above should catch it.

Jon.

I noticed that the needle sticks in the seat when I have the horn assembly sitting upside down for a while when the carb is apart. I have to shake it for it to fall onto the float tang. However, I would think that would restrict fuel though.

Jon - Thanks for the checklist. Is there a procedure for checking the accelerator pump discharge check valve when the carb is apart?

When the needle was sticking on my rebuild, it was becuse the original did not use the spring retainer on the needle. I installed the one from the kit and it was causing binding. I took it out and the needle was free and no longer stuck.

Just another opinion...

A quick way to check if the needle is working with the float is to blow air (with your mouth) into the carb where the gas comes in. If you turn the carb over while you are blowing, it should act as though the float came up and you should not be able to blow air in anymore. Its pretty low tech but an easy check as long as you have the carb off.

One thing that I've found with Rochester "B" carb kits is that the seat that comes with the kit is drilled but not chamfered. The original has a chamfer in the hole that the needle fits. I take one of the old check balls out of the carb, and drop it onto the new seat, then tap it lightly with a punch and hammer. This puts a chamfer into the brass and seems to keep the needle from sticking. I have been on the same rebuild for 4 years on the "B" on my 261 with no sticking or flooding. Before that it would stick and flood every other time I drove it.

Insure that the floats are not coming in contact with the sides of the bowl.

I'm pretty confident with the float settings. It makes sense that a chamfer in the seat would work.

I've got it back on so I'm hoping for success.