Here is a redundant question I'm sure.
What should the float level be on a Holley G carb?
Chris, I'm not sure there is an honest dimension that you can go by with a G. The carb needs to be bolted to a fixture with a "fuel tank" above it and with the top three screws and the top plate removed you have to verify that the idle pickup tube is in the puddle and not above it. The float setting is determined by the height of this puddle. It is a pain in the neck.
If the car is a driver and not a show car, I would consider a later carb like an NH or an L4. Usually the venturi in the G is junk and a new one is $25.
When setting one of these early carbs (G) don't use gasoline! Use mineral spirits. The reason is you will drain it and have the bowl off a few times in order to get it all correct.
You know I was going to order a new Venturi but decided that it probably was alright. LOL That's the way it goes.
Thanks for the info Gary, I will go out now and get it set up, got a parade coming up pretty quick need to get it ready.
I will look into getting the NH carb soon.
There is some information at
And I checked but could not find the thread I had saved, so I am re-posting it. A little wordy but it has some good info also. Our T has run ok with the Holley G. It is basically a lawn mower type puddle carb -- but it runs ok. Below is a previous posting on the Holley G. I hope that helps.
Model T Ford Forum: Forum: Leaky Carb.
By Mike Walker (Waterwalk) on Tuesday, April 27, 2004 - 10:23 pm:
Hello, All -- I have rebuilt the Holley G carb on my '15 Touring, but I can't keep it from leaking when it's not running. It's not a big leak, but it's enough to make the garage smell of gas overnight. The one thing I wasn't able to replace when rebuilding it is the float needle & seat (I guess that's 2 things), because I couldn't find a listing for them in any of my catalogs. Does anyone know of a source for them? Or does one from another carb, such as an NH, fit a G? I can't think of anything else which would let it ooze gas like it's doing. I polished the needle with a buffing wheel & there's no groove in it, but it still doesn't seal. Thanks for any advice/guidance in sorting this out.
By Thomas Mullin (Touringtom) on Tuesday, April 27, 2004 - 11:12 pm:
Does your float cut off the fuel inlet to the bowl properly?
Is there a leak from the upper part of the carburetor, possibly behind the name plate? I understand there is a vent hole in most carburetors.
Until you find the problem, you might want to start turning off the valve at the gas tank every night.
By Mike Walker (Waterwalk) on Wednesday, April 28, 2004 - 06:17 am:
I didn't mention it, but I do shut off the fuel valve every night. It leaks anyway.
By Royce Peterson (Roycep) on Wednesday, April 28, 2004 - 08:06 am:
I had the same problem on the Holley G for my 1915. In my case the float was not bouyant enough to close the seat tightly. A new composite float from Chaffin's fixed it.
By Mike Walker (Waterwalk) on Wednesday, April 28, 2004 - 11:05 pm:
Hello, Royce, et al -- I replaced the float with the new composite one from Snyder's. It's probably the same one that Chaffin's has available. Everything's new except the needle & seat. What mystifies me is that when I come home from a drive, I immediately turn off the gas at the carb (I bought one of those $20 90-degree shut-off valves from Snyder's), but it still leaks during the night and the next day, and it's oozing down the outside of the bowl, which seems to me like it's the needle and/or seat, but why would it be leaking with the gas shut off? I just don't understand it. Thanks for your input, guys, please keep it coming until we come up with a solution. In the meantime, does anyone know of a source for a new needle & seat for a G?
By Ken Todd (Katy) on Thursday, April 29, 2004 - 10:51 am:
It sounds like your shut-off valve is weeping.
If it's a plug valve as I suspect it is you should disassemble and inspect it for scores or high spots on the plug or the body.
You may have to lap it to effect a better seal.
By Robert Bowes (Bobb) on Thursday, April 29, 2004 - 12:58 pm:
Mike, I have the same problem with my 26 Tudor, mine has a NH carb and metal float.
It only sticks/leaks if the engine is very warm from an extended drive, the end of the driveway and back won't do it... 10-15 miles out and back and about 1 in 10 times it has leaked.
I'm wondering if has something to do with all that heat and the bowl full of gas, perhaps evaporating it, letting the float drop, drying out the pivots on the float (no road bumps to slosh the gas around) or the little ball that pushes the needle gets dry and sticks...
The only fix for me has been to drop the bowl, manually manipulate the float a few times and re-assemble. This last time I took the whole carb off, and was able to bend the tab on the float to shut off a little bit "earlier" or with a lower fluid level in the bowl...
It has not done it since, including 3 drives over 30 miiles each. (fingers crossed)
Because of several occasions of leaks and the gas smell, my wife has instisted I park in the driveway first for a couple hours to let it cool off, then just a quick start and back in to it's parking spot.
I guess the concept of shutting of the gas every time should be part of my way of driving, 10 gallons gravity feed, means a big mess / fire if something let's loose.. Even if you do shut off the tank, on a '26 with the up front tank, I could still loose enough from what's in the tubing down to the carb to "smell" but probably not enough to burn down the place...
By Michael Pawelek-Brookshire,Texas (Michaelpawelek) on Thursday, April 29, 2004 - 02:00 pm:
Robert, On your NH are you using the float needle with the Neoprene tip? I had leak problems for years but now run 3 NH carburetors with Neoprene tips and have no leaking at all. They appear to seal better than the original all metal float needles...Michael
By Kip Carlin (Mrwood50) on Thursday, April 29, 2004 - 06:06 pm:
I agree with Michael, i changed to the Neoprene tip, and have had no problems at all.
By Mike Walker (Waterwalk) on Thursday, April 29, 2004 - 09:36 pm:
Well, I'm embarrassed to say that I was mistaken about the gas running down the side of the bowl, which changes everything. (It was doing that a while back, but I guess it's not now.) Apparently what's happening is that it's leaking from the bottom, around the nut. As I said, it leaks overnight and the next day or so. But after that, it stops. I opened the bowl drain valve tonite after the car had sat for 3 days, and the bowl was empty. I had tightened the bowl nut very tight last time I worked on it, thinking that the leak might have been there and that I'd stopped it. I guess that maybe I need 2 gaskets between the bowl and carb body to add some thickness to it. Anyway, thanks for your help, everyone. I'll do a little more homework next time before asking a question here.
By Thomas Mullin (Touringtom) on Thursday, April 29, 2004 - 09:47 pm:
No problem at all. I learned a lot from the responses and suggestions.
Glad you found the problem.
By Roy Stone WV (Roystone) on Thursday, April 29, 2004 - 10:58 pm:
Mike, have you checked for a crack in your bowl.or has your bowl been sprung (by being overtighting). Hope some of these ideas helps. Roy
By Mike Walker (Waterwalk) on Sunday, May 02, 2004 - 10:57 am:
Well, I always wonder how things came out when someone asks a question & gets several suggestions, so I'll post an update on what I found. I took the carb all apart again, and measured the height of the bowl against the faces where it fits onto the carb body, and the bowl is 1/16" taller. I made an extra gasket (slightly less than 1/16") to use in addition to the one which comes in the gasket kit for the carb. That stopped the bowl leak. My float needle & seat didn't pass the "needle valve leak test" (p. 2) in the MTFCA Carburetor book before. The book suggests tapping lightly on the needle to seat it, which I had done. This time I tapped it a little less lightly, and now it seals.
I had set the float parallel with the carb body before (I thought), but I noticed when I took it apart that it was higher than parallel. So I re-set it a little below this time, to effect a positive shut-off. The book describes in detail how to fine-tune the float setting, except I'm not clear on where the fuel level is supposed to be. Fig. 121 in Picture #30 on page 11 shows the fuel level 1/16" above something, but I'm not sure what. Is it 1/16" above the top of the spray needle seat? How critical is the fuel level adjustment? Is it worth going to all the trouble they describe in the Carb book to get it just right? I'm determined to conquer this, so any help will be appreciated, as always.
Hap -- Thanks for posting that. Reading it now was "like deja vu all over again". My car ran well with the Holley G, once I got the leak taken care of. This past winter I went thru the engine to "freshen it up" a bit. The aluminum pistons and rings were still good from the rebuild 15 years ago. I snugged up the rods and mains, and replaced the rear main cap to get a new thrust face. New mag ring and stainless valves, and a new Stipe 250 cam. It also has the Performance T Parts high-compression head, installed last year. I had tried several different carbs on the car before, but couldn't tell much difference. With the freshened motor and new cam, I ran the G for a month or so. It ran fine. The cam was the only real change from before, and it made quite a difference, especially going up hills. It has more low-end torque. Then I tried my straight-thru Wizard (Simmons) again and can tell a noticeable difference. It starts easier and runs smoother than with the G. I guess the cam made the engine better able to utilize the efficiency of the straight-thru carb. Whatever the reason, I'm tickled with the combination of parts I now have.
Mike Walker asked 28-Apr-04 whether anyone knew of a source for a new needle & seat for a G.
I noticed there is a modern 2 ball style valve for the Holley G (eg 6212GJG at Lang's).
Does anyone know where the standard (or one with neoprene) needle and seat for a Holley G can be found?
In Plate No 14 below, what are the part numbers for the standard Holley G needle and seat? 4453A and 4473A?
Float level: the float measures 1/2 inch from machined flange on mixing chamber to float per Murray Fahnestock The Model T Fordowner page 194