65 396 holley carb, still leaks?

[William B.]

65, 396/425 coupe, carb rebuilt by previous owner and he could never get the leaks to stop. I have been working at it, 4 new gaskets on both end bowls, new washer on all bolts and the top float adjusting screws.
Problem while running it seaps out the top float adjusting screws and after you shut it off it leaks around the bowl screws. Have tried to make them as tight as I can without breaking off the top screws and bowl screws.
Thinking about changing the bowls screws to bolts just to get them tighter. Anyone have any solutions or suggestions?

[Timothy B.]

Re: 65 396 holley carb, still leaks?

William,

Could it be the screws are too tight distorting the gaskets. If everything is tightened to the point you are afraid of stripping the threads something is definately wrong. Fuel leaking out the top float adjusting lock down is a sign of improperly adjusted float or missing gaskets.

Take everything apart carefully and check for flat surfaces at the main body and even the float bowls around the perimiter and don't use those cork gaskets. Over tightening can pull the area where the bowls thread to main body and need to be filed flat and possibility helicoiled if the threads are marginal.. Just a little tighter than snug gets it done.

[Joe L.]

Re: 65 396 holley carb, still leaks?

65, 396/425 coupe, carb rebuilt by previous owner and he could never get the leaks to stop. I have been working at it, 4 new gaskets on both end bowls, new washer on all bolts and the top float adjusting screws.
Problem while running it seaps out the top float adjusting screws and after you shut it off it leaks around the bowl screws. Have tried to make them as tight as I can without breaking off the top screws and bowl screws.
Thinking about changing the bowls screws to bolts just to get them tighter. Anyone have any solutions or suggestions?

William-----


Forget about changing the bowl screws to bolts "to get them tighter". That will either exacerbate your problems or create new ones. Or BOTH. You definitely have other problems that need to be addressed which are the root cause of your leak problems. Most likely, your mating surfaces are "warped". This is a common problem with Holley carbs (often caused by guys applying "gorilla" torque to the bowl screws).

[William B.]

Re: 65 396 holley carb, still leaks?

OK, tonights project will be to see if the mating surfaces are straight.
But I am not leaking around the mating surfaces. My leaks are at the float adjusting screw while running and after the engine is shut off it leaks around the lower bowl screws in the rear of the carb.

[Joe L.]

Re: 65 396 holley carb, still leaks?

OK, tonights project will be to see if the mating surfaces are straight.
But I am not leaking around the mating surfaces. My leaks are at the float adjusting screw while running and after the engine is shut off it leaks around the lower bowl screws in the rear of the carb.

William-----


Very often the exact source of a fuel leak can be almost impossible to discern. While the fuel may APPEAR to be leaking from a certain source, it may be coming from elsewhere.

However, I'd say the leak from the adjusting screw area may very wll be caused by too high a float level as Chris previously mentioned,

[Ken A.]

Re: 65 396 holley carb, still leaks?

OK, tonights project will be to see if the mating surfaces are straight.
But I am not leaking around the mating surfaces. My leaks are at the float adjusting screw while running and after the engine is shut off it leaks around the lower bowl screws in the rear of the carb.

Get a GENuine Holley rebuild kit and set the float level w/ a drill bit. Don't worry about drop. Your goal is to be slightly below the "sight" window. Do you know how to set the floats? Are you using a 5/8 wrench & large screwdriver? Do you have BOTH gaskets for the needle assembly? Use either nylon or Holley gaskets for the bowl screws. As they have said, "do not over tighten". The Holley gaskets should compensate for a wraped main body. If it still leaks, then you need to send to a pro.

[William B.]

Re: 65 396 holley carb, still leaks?

I am trying to correct leaks by a previous person unkown to me. I think my best bet is get a holley rebuild kit and take my time do everything correct. Thank you for all the replies, I am going to plan "B"

[Timothy B.]

Re: 65 396 holley carb, still leaks?

William,

One other thing to think about is the fuel pump pressure. The needle and seat may not be able to hold it back. I think approx 5 1/2 lbs is good pressure for our cars. I agree with Joe about the difficulty to locate the gas leaks.

I found on my 3810 that the throttle plare screws had pulled the aluminum in the main body and previous rebuilder installed a thicker gasket and I needed to file some to flaten then install a thinner gasket. If it's a original carb it is definetely worth the extra effort to fix correctly.

[Joe C.]

Re: 65 396 holley carb, still leaks?

If the bowl gaskets are intact and sealing against a relatively flat surface, all bowl screw washers are in place, and there are no hairline cracks or porosity problems, then the bowls will not leak with an excessively high float level or fuel pressure in excess of 6-7 psig, which is ideal. In this case, excess fuel will dump into the throats through the boosters.

[Jack H.]

Re: 65 396 holley carb, still leaks?

Correct/original 3124 carbs are about as rare as hen's teeth! They were often replaced during the early years of the car's ownership with service replacement carbs...

The suggestion(s) made by others that you might be fighting a component warpage issue could be ON THE MONEY. If that's the case, all the rebuild kits in the world aren't going to remedy the situation and it's time to send the carb off to a Holley restoration pro...

Personally, I like Jerry Luck, but others have their own favorite sources and opinions. I've seen some pretty BAD work done on carbs folks sent directly to Holley...

[William B.]

Re: 65 396 holley carb, still leaks?

Retightened the 8 bowl screws last night, I think after the carb goes through a heat and cool cycle, the screws must be retighned. The carb also had white plastic washers under the float adjustment screws, replaced those with the origional holley fiber washers and so far no leaks, time will tell and I am going to keep a close eye on it.