The Ford Barn

PC/SR · 11-26-2012, 06:59 PM

I have dual 92's on a Model A Speedster. Doing some timing and vacuum checks the other day, and noticed that at 2300 rpm gasoline started leaking down the vertical shafts that go up into the carb body that actuate the accelerator pump. Does this on both carbs. Below about 2200 the flow stops.
They were rebuilt last year with new throttle shafts, gaskets, etc. No leakage from throttle shafts. I have an electric fuel pump, 2 lbs psi at the carbs. Float height is correct, with no leakage anywhere when just running the fuel pump with engine off, or running up to 2300 rpm. It has a hot cam, and very slight flutter, less than an inch, on the vac gauge at 2300. Max timing is 27* advance at 2700 rpm, an FSI mechanical advance distributor.
Again, the leak comes down the vertical shaft out of the carb body, not the throttle shafts or anywhere else.
I dont get it. Anyone else hear of this, have any ideas? The 94’s were built virtually the same way so any experience with them might give a clue. Thanks for your thoughts.

ken ct · 11-26-2012, 07:19 PM

If theres rubber type accelerator pumps in them the pumps dont fit the bore well and gas leaks up over the AP and fills up the upper chamber and has no place to go but out the uprite shaft.,find some old style leather type ones [good luck]to replace the rubber ones. set floats slightly lower.I set 1 7/16" ken ct.

1952henry · 11-26-2012, 07:31 PM

Good call, Ken. I have some NOS 92 pumps, but are not in the same zip code as I am.

PC/SR · 11-27-2012, 12:12 PM

Ken ct: Are the 92 pumps the same as the 94's?
1952 henry: Sent you an email.
Thanks to both for the response.

ken ct · 11-27-2012, 12:40 PM

NO there smaller diameter cups. 52 Henry has some he says. ken ct. Older used leather ones can be reused if not too dry and are not shrunk or split,if you soak in motor oil for approx 1 minute,then pat off the excess before inserting into carb. ken ct.

ford38v8 · 11-27-2012, 10:03 PM

Sponsored Links (Register now to hide all advertisements)

So Ken... I guess they don't make cows like they used to? What's the big deal, it's only leather?

ken ct · 11-28-2012, 12:56 AM

Even used leather ones work better that the new rubber ones if treated to an oil bath first and are not split or shrunk a lot and the spring is in good shape. ken ct.

ford38v8 · 11-28-2012, 01:38 AM

Ken, I meant... oh hell, never mind.

11-26-2012, 06:59 PM	#1
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,278	Holley 92 carb leak I have dual 92's on a Model A Speedster. Doing some timing and vacuum checks the other day, and noticed that at 2300 rpm gasoline started leaking down the vertical shafts that go up into the carb body that actuate the accelerator pump. Does this on both carbs. Below about 2200 the flow stops. They were rebuilt last year with new throttle shafts, gaskets, etc. No leakage from throttle shafts. I have an electric fuel pump, 2 lbs psi at the carbs. Float height is correct, with no leakage anywhere when just running the fuel pump with engine off, or running up to 2300 rpm. It has a hot cam, and very slight flutter, less than an inch, on the vac gauge at 2300. Max timing is 27* advance at 2700 rpm, an FSI mechanical advance distributor. Again, the leak comes down the vertical shaft out of the carb body, not the throttle shafts or anywhere else. I dont get it. Anyone else hear of this, have any ideas? The 94’s were built virtually the same way so any experience with them might give a clue. Thanks for your thoughts.

11-26-2012, 07:19 PM	#2
ken ct BANNED Join Date: May 2010 Location: stratford,ct Posts: 5,971	Re: Holley 92 carb leak If theres rubber type accelerator pumps in them the pumps dont fit the bore well and gas leaks up over the AP and fills up the upper chamber and has no place to go but out the uprite shaft.,find some old style leather type ones [good luck]to replace the rubber ones. set floats slightly lower.I set 1 7/16" ken ct.

11-26-2012, 07:31 PM	#3
1952henry Senior Member Join Date: May 2010 Location: North Dakota Posts: 1,615	Re: Holley 92 carb leak Good call, Ken. I have some NOS 92 pumps, but are not in the same zip code as I am. __________________ I dig coal, which provides motivation for EVs.

11-27-2012, 12:12 PM	#4
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,278	Re: Holley 92 carb leak Ken ct: Are the 92 pumps the same as the 94's? 1952 henry: Sent you an email. Thanks to both for the response.

11-27-2012, 12:40 PM	#5
ken ct BANNED Join Date: May 2010 Location: stratford,ct Posts: 5,971	Re: Holley 92 carb leak NO there smaller diameter cups. 52 Henry has some he says. ken ct. Older used leather ones can be reused if not too dry and are not shrunk or split,if you soak in motor oil for approx 1 minute,then pat off the excess before inserting into carb. ken ct.

11-27-2012, 10:03 PM	#6
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 6,633	Re: Holley 92 carb leak Sponsored Links (Register now to hide all advertisements) So Ken... I guess they don't make cows like they used to? What's the big deal, it's only leather? __________________ Alan

11-28-2012, 12:56 AM	#7
ken ct BANNED Join Date: May 2010 Location: stratford,ct Posts: 5,971	Re: Holley 92 carb leak Even used leather ones work better that the new rubber ones if treated to an oil bath first and are not split or shrunk a lot and the spring is in good shape. ken ct.

11-28-2012, 01:38 AM	#8
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 6,633	Re: Holley 92 carb leak Ken, I meant... oh hell, never mind. __________________ Alan

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