Inliners International Forums General Discussion Engines 1 BARREL CARBURETOR LEAKING!!! (HELP!!!!)

This is the original 1 Barrel Rochester BC Carburetor that sits atop a 235.5 cid "blueflame" Inline Six engine!!! The car is a 1955 chevrolet, but now it's 52 Year old Carburetor is leaking fuel onto the hot exhaust manifold!!!! The carb. was fine until recently, when the glass fuel filter was broken by my wife and very dark contaminants passed into the mechanical fuel pump and then into the carburetor. Now the car dies when going uphill and leaks fuel after a 2-3 min. starting warm-up!!! From a cold engine the 55 starts o.k. then after 2-3 min. a small leak starts from the top of the carb., near or in the Choke shaft area. The leak seems to start with a few fuel droplets apparently coming from the choke shaft end where the idle arm connects to, on the throttle linkage side facing the driver!!! First a drop or two, then a steady repetition of drops and after 3-4 min. of the engine warming up the drops become a spritz spray that pours all over the hot exhaust manifold, potentially creating an engine fire!!!!!


_________________________________________________


O.K., i installed a brand new performance clear glass in-line fuel filter w/micro mesh steel screen so i can see any "Contaminants" that may try to pass through the fuel lines!!! So far, all fuel appears clean and clear!!


Then, i removed the Carbuetor from the intake manifold! Took apart every piece (like a rebuild, but without new parts!), used a whole can of carb. cleaner & pulled out about a 1/3 of a cup of dark red "rust"? powder!!! - washed out and blasted (with an air compresser) all passages, ball bearing, springs, ports, inlets, outlets and of course the fuel bowl and every other part in the carb.!!!! I Re-assembled and re-installed the Carburetor back onto the intake manifold. Re-attached all lines and linkage, poured 1/2 cup of gas into the carb. and started her up!!!


The fuel going to the carb. stay'ed clear with no leaks around the fuel filter!! The engine started staight up and maintained a steady rate with excellent timing!!(no misses!). The 55 chevy ran for about 35 seconds with no problems when suddenly, gas started to shoot out with ever increasing pressure on the linkage side of the carb.!!! Like last time it seemed to be coming straight from the throttle linkage. But, i think it's more probable that it's coming from the top of the carburetor, nearby or in the choke shaft and it's end that links the idle linkage to it and then the fuel splashs down onto the throttle linkage and then onto the hot exhaust manifold!!?!! I noticed a bit of play on the end connection of the choke shaft where the idle arm attaches....it wiggles maybe a millimetre? or so!!! Could the gas leak be coming from there??? I tried to tighten the connecting screw and all other possible loose parts but this did nothing!! When i was cleaning the Carb. and i saw all that dark red rust powder (1/3 cup+) in the fuel bowl and all other interior parts of the carb., i thought this must be the problem!! Clogging some passage or part, causing the fuel to continue to fill the carb. until it reachs the height of the choke shaft and ejects out through the choke shaft's end!!! Am i wrong??, because after the carburetor's cleaning - the leak is now happening even quicker with even more fuel spilling out now than before!!!!


HELP!!! I spent over 4 hours making sure the Carburetor was perfect!! And it is running the engine perfectly, the only problem is this **** mystery leak!!!!!!!


Any idea's on what's happening and on how i can fix my "1 barrel - ROCHESTER BC , 52 year old CARBURETOR???????????? HELP!!!!


"Fla54Chevy3100"

Suggests:

"My guess is that there is some trash stuck in the float needle and valve assembly, Your description sounds like it is flooding because the float is not able to cut off the fuel flow in the bowl and just continues to pour gas into the carb. I would start there, an easy fix".

So o.k., should i take off the Carburetor again and double check the float assembly and assoc. parts?? I thought i had done a good job overall, but i remember now that i didn't use the air compresser on the float assembly! (just sprayed carb.cleaner in and around the needle and float area.) Seemed o.k., but maybe i should re-do with more attention there! What do you guy's think????


Don't know what else to do!!!

Islandman!!

Check to make sure the float isn't sinking. Remove the float hold it up near your ear and shake to see if you near gas sloshing if so replace float. Then make sure float is adjusted properly. While you have float out double check needle and seat area for debris.

You MUST solve the contamination problem first!!

The needle is staying open due to this and the fuel level inside the carb is to high.

The debris (perhaps rust) is so fine It's going through your filter and this is why it runs okay after youve cleaned it etc.

Clean or replace the tank.

Good luck.

THANKS GUYS!!!


I will take the top of the Carburetor off and check the float for leaks as well as blast air thru all passages and all surfaces!!! I'll then re-assemble the Carburetor and test for leaks!!!

I read a tip on leaking Carburetors and it said you should take a silicone gasket seal making material (like the type used in engine assembles!) and coat the Carburetor gasket on both sides with your finger. Let the gasket dry/set overnight and install in your Carb. The tip say's any and all leaks around the gasket area's would be completely gone!!!

What do you think????

I would be really surprised to find that even fine rust powder could get past my fuel filter! The only time contaminants got past it was after it was accidently broken by my wife and was replaced temporarily by a hose coupling! The fuel filter is located on the passenger side of the engine away from all heat sources and with nothing under it in case of leaks. This is a High Performance Fuel Filter that has a clear glass cylinder and a super fine micro-mesh that can be removed, cleaned and re-used!!! But i see your point "John H. Meredith"...


I'll fix the fuel tank problem after the Carburetor's fixed. I know contaminants are coming from the tank, but when this fuel filter is on, it seems to capture everything!! I will keep a close eye on the filter and try and fix the Fuel Tank A.S.A.P.!! I need to have the 55 running to get it fixed (I.E. take to shop), as well as it's our only vechile!!! I Still don't know how i'm going to get the tank clean while it's still attached to the car!! I can't afford to do the "radiator shop, flush and seal" idea or replace the tank at this time. So when i get to the tank how do i flush it?? Do i use diesel fuel or is there a better cleaner or a better way of solving my problem??

Any Idea's??????

By the way, "John H. Meredith" I noticed that you've "posted" almost 2500 times!!! WOW!!, Are you one of this site's ("Inliners International") creator's????

Thanks for all your help and hoping for a solution.....


Islandman

No; I am not one of the Club's creators. Just one (of the many) that has the time/desire to assist here.

If your vehicle wasn't vandalized, someone may have poured a (rusty) can of gas in W/O knowing etc. Whatever the origin; your problems are going to continue untill its removed completly.

You could install a 'sediment bowl' ahead of the fuel pump, but that not a job for a novice, so flushing the tank is what's needed.

If you persist in your present course a fire/explosion is quite possible!! So please GET someone with experience to HELP, BEFORE that happens!!

Good luck.

Hey thanks everyone for the advice!!!

HOORAY!!!!

The Carburetor is fixed!!!!!

The culprit was debris that got lodged in the upper portion of the Carburetor, not in the needle valve area but in one of the other small passages!!! Blasting all area's with the air compressor was the best way to clean the Carb.!!!


This "Contamination" got into the Carburetor because the fuel filter was off for a short time!! The high performance fuel filter is located before the fuel pump and the fuel appears to be clean, so far...

Anyone with with advice on, "How to clean your fuel tank (flush/seal), without taking it off your vechile" is gratefully welcomed!!!


With only one last problem to solve....

Islandman

You can unscrew the plug in the bottom of the tank and see if setiment comes out as it drains. I would do this with only a gallon of fuel in the tank and in a well ventilated area with NO sources of heat or spark nearby. The best as has been suggested is to remove the tank. It's really not that hard especially if you have a manual to follow.