C3 69 - 3x2 Carb question

[John A.]

I have been having a problem with fuel flooding into the manifold and I’m not sure what its root cause it. I did read Keith Kibbe’s Restorer article “Holley Internal Leaks” and it got me thinking that this may be a common problem with other Holley carbs. I figure others with the 3x2 setup may have experienced this before and may be able to share their experience. (great Restorer issue!)

My problem is a bit more acute. I was actually driving the car when it seemed to become overwhelmed with fuel. I managed to get it home without it stalling. When I tried to restart it for troubleshooting, it would not start – flooded! I pulled all three carbs and slowly did an open and inspect. There were no obvious signs of anything failing. But there was about 1/4 inch of fuel pooled in the manifold. I replaced the PV, needle and seat and the metering plate gaskets (in all three carbs). The floats looked good. The only gasket I did not replace was the base-to-body gasket, but did tighten the screws. Still haven’t been able to get it started – and yes, I checked the timing…

Anyway, to make a long story short, if the base to body gasket is dry and not sealing, can the bowel fuel leak into the manifold if left to sit for a week? Can the engine suck fuel past that gasket if it’s not sealing completely?

Sorry for the long post... Appreciate any and all responses…

Thanks

[Marc R.]

Re: C3 69 - 3x2 Carb question

I don't know what you mean about the floats 'looking good' but from personal experience I can tell you that floats can become saturated and will cause a similar problem.

[Marc R.]

Re: C3 69 - 3x2 Carb question

I don't know what you mean about the floats 'looking good' but from personal experience I can tell you that floats can become saturated and will cause a similar problem.

[Clem Z.]

Re: C3 69 - 3x2 Carb question

the nitrophyl floats in the end carbs should weight 10 grams and the brass float in the center carb can be shaken to listen for gasoline inside.to remove gasoline from the inside of a brass float just put it on boiling water and you will see the bubbles where the hole is and also the gasoline will boil out. just solder up the hole and you will be fine. do NOT use your mrs pots or pans to do this as the gasoline smell will not come out. don't ask how i know this to be true. i now use a old coffee can on a electric hot plate. your problem sounds like parts warpage causing your leak thru

[Clem Z.]

Re: C3 69 - 3x2 Carb question

the nitrophyl floats in the end carbs should weight 10 grams and the brass float in the center carb can be shaken to listen for gasoline inside.to remove gasoline from the inside of a brass float just put it on boiling water and you will see the bubbles where the hole is and also the gasoline will boil out. just solder up the hole and you will be fine. do NOT use your mrs pots or pans to do this as the gasoline smell will not come out. don't ask how i know this to be true. i now use a old coffee can on a electric hot plate. your problem sounds like parts warpage causing your leak thru

[John A.]

Re: C3 69 - 3x2 Carb question

Hi guys,

Yes, the center brass float has no fuel in it and I'm told that the nitrophyl floats wont soak up fuel (styrofoam like). But, I will double check / replace them. Also, I did check the bowl leverl and they were not over full.

As far as the warpage, its hard to say... its a 2 barrel, so the total surface area is not that much. Question is, can fuel be sucked through that gasket if its old or the base plate screws aren't tight?

Thanks

[John A.]

Re: C3 69 - 3x2 Carb question

Hi guys,

Yes, the center brass float has no fuel in it and I'm told that the nitrophyl floats wont soak up fuel (styrofoam like). But, I will double check / replace them. Also, I did check the bowl leverl and they were not over full.

As far as the warpage, its hard to say... its a 2 barrel, so the total surface area is not that much. Question is, can fuel be sucked through that gasket if its old or the base plate screws aren't tight?

Thanks

[dick foehringer]

Re: C3 69 - 3x2 Carb question

i have seen the center carb leak thru the accelerator pump pass thru port due to the body being warped. take the bowl and block off and put a straight edge on the body. to fix it i use a metal plate sander block with 80 grit and sand it flat till everything shows sanding marks. this happeded on a holley i had on a Z28. it leaked so much gas into the engine i could see fuel flowing thru a clear filter at idle!! the exhaust pipes were even wet with fuel. let us know what you find.
regards dick

[dick foehringer]

Re: C3 69 - 3x2 Carb question

i have seen the center carb leak thru the accelerator pump pass thru port due to the body being warped. take the bowl and block off and put a straight edge on the body. to fix it i use a metal plate sander block with 80 grit and sand it flat till everything shows sanding marks. this happeded on a holley i had on a Z28. it leaked so much gas into the engine i could see fuel flowing thru a clear filter at idle!! the exhaust pipes were even wet with fuel. let us know what you find.
regards dick

[Dick W.]

Re: C3 69 - 3x2 Carb question

If whoever told you that the floats would not absorb fuel really believes that, I have a deal in ocean front property in Sedona. If you can find an old mechanic that has a float scale, get him to weigh it. Clem said 10 grams. Anything heavier than that trash the old float.

[Dick W.]

Re: C3 69 - 3x2 Carb question

If whoever told you that the floats would not absorb fuel really believes that, I have a deal in ocean front property in Sedona. If you can find an old mechanic that has a float scale, get him to weigh it. Clem said 10 grams. Anything heavier than that trash the old float.