Inliners International Forums General Discussion Engines Rochester carb leaking! Help!

I have a 1951 chevy with the 216 and I am having fits with the carb! After messing around with it trying to fix all the leaks I bought the chevy of the 40's kit (new gaskets) installed them and...it STILL LEAKS! The leak is right where the gasket is between the top of the carb and bowl. I tightened down the slotted head bolts as much as possible but it still leaks. I am VERY frustrated with this carb. I have a 235 (not running) in a parts car that I want to restore so I don't want to replace the rochester in the 216, only get it to stop leaking!
p.s. the motor does run, the carb does work it just LEAKS OUT THE BRAND NEW GASKET!!!!!!!!!!
Any help is GREATLY appreciated
Aaron

The problem with these carbs is that the top cover gets warped due to overtightening. New gaskets can't stop this. Check the archives at Stovebolt.com for more info - I think there is a rebuild service that re-machines the top of the carb to fix this.

Check out the 12PN, May/June 2004, Pg 20. The bowl cover gasket could be interfering with the float and holding it down causing the flooding.......JOE

Dear Aaron;

Joe's right, it may be the float/gasket. Or it could be the float/seat. Or that adjustment & the gasket is okay.

So check that too.

Good luck. John M......

Thanks for the replys. I am thinking that the carb is warped. Even if the float is not closing gas still shouldn't pour out between the 2 halves of the carb where the gasket is. Unless I am missing something??
I have another carb that I don't think is warped (didn't leak out the sides only through the throttle slide)so I am going to swap out all of the new parts into the other carb. Hopefully that'll work.

Tip. Before you rebuild another old carb that may leak check the bowl gasket surfaces with a small straightedge for warpage or distortion. Alternately you can use a sheet of glass on the bench and lay the carbs mating surfaces on it and using a set of feeler gauges check for flatness that way. Typically you'll find the screw bosses making contact and the area between the screws leaving a gap against the glass. Minor distortions can be corrected by laying a full sheet of 220 papar on the glass and carefully running the carb pieces over it until the high spots are knocked down. When you think you have it smear a little coating of grease on one half of the carb and put the top on by hand pressure and not using the screws. Lift the top back off and check for full contact as shown by the grease wetting the other surface.

Mike ( by necessity a rebuilder of a lot of old junk )

Thanks for the tip Mike, I'll have to try that out, since, my other carb is leaking. One question, I really had to torque down the bolts (in a star pattern) before the gasket would stop wiggling in the middle. I guess this kind of proves that the halves are warped?
I also still have a leak out of the throttle slide where the leather plunger is, and tips on why a new plunger would leak?

Had same problem, new fuel pump was to much for the old carb. Installed an adjustable inline fuel press. regulator, problem solved. These are the chrome units, that allow you to set pressure from about 1 lb to 5 or so, mine liked 2 lb setting.

Aaron if you are talking about fuel leaking from the bottom of the bowl where the accelerator pump shaft sticks out then it is related to the bowl gasket not sealing. You're probably getting fuel spilling over through the gasket area from the float bowl. Fix the warpage and get the 2 halves of the carb body to seal nice and flat and life will be good again.

I have a couple extra Rochester B model carbs if you need a particular part from one - I was going to ebay them since I got mine working right again but if you need a part from one let me know .

I can send photos if you want .

Thanks for the replys!
Mike, so the plunger isn't necessarily the problem, but the gasket. The fuel leaks out the slot where the accelerator slide is.
I bit the bullett and ordered a "new" carb so hopefully that will fix my woes. I didn't want to spend the $$ but oh well, if it doesn't leak and works properly it'll be worth it.

Oh well, Guess you have it taken care of . Good luck !
Randy.

Leakage from where the accelerator pump shaft goes through the bottom of the carb is not something that can be stopped completely as there is no seal involved. Keeping the float level and fuel pressure in check are all you can do. It shouldn't be running out, but will develop a "film" over the parts in that area over time. Nature of the beast, sorry.

As for a warped air horn, filing or whatever will end up removing the "bead" that runs around the edge for sealing. If the carb is truely warped, toss it and fing one that isn't. Most are fine, I have yet to find one that is warped, personnally. Just make sure it is for a 216, as the 216,235 & 261 all used this carb and the throttle bores are all different, and the 216 has a smaller bolt pattern as well. You would want to look for one witha 1 1/2" bore and approx. 2 3/4" bolt pattern.

Another option to correct warping is to get a 1/2" thick piece of steel plate and drill and tap mating holes to the upper half of the carb body. Screw this to the plate and put it in the oven. (obviously you have removed all gas and rinsed first)

Fire at 300 degrees for an hour and it will come out flat. Use proper torque when re-assembling and it will not warp again.

oi vey,yah'll goin over the top on this one,yes old rocky singles leak from being warped when rebuilt and all that,well i got this tip from an old timer,its cheap and work like a charm. take the top off,and get the tube of vasoline out of the medicine cabinet,carefully smear a bead of vasoline around the gasket keepin it towards teh outside of it,put the top back on,and 8 times out of 10 it works.