Carb Weeping and Choke when Warm

Farmall Super A, AV, 1939 - 1954

Moderator: Team Cub

Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.

Carb Weeping and Choke when Warm

Postby Ironlegs » Tue Dec 11, 2012 9:09 am

I replaced the original Carter carburetor on my 1951 Super A with an apprropriate new Zenith carb last fall. Performance was awesome...until recently. The new Zenith has a plastic/rubber tipped float valve. I noticed that fuel slowly weeps/seeps from the fuel bowl drain when the engine is off and when the tank shut off is open. When running, some choke is needed to keep running smooth and to optimize power. The new carb was removed, cleaned and the float checked and set to 1-5/32 inches (Zenith spec)...only a very minor adjustment needed. The unit's governor is fine and the ignition system, valves and timing are spec. Can some definitively tell me what's needed to restore performance?
Ironlegs John
Ironlegs
Cub Star
Cub Star
 
Posts: 80
Joined: Tue Aug 21, 2012 10:21 am
Location: McKean PA
Zip Code: 16426
Tractors Owned: 1951 Farmall Super A
1958 Farmall Cub
Circle of Safety Award
Circle of Safety: Y

Re: Carb Weeping and Choke when Warm

Postby Don McCombs » Tue Dec 11, 2012 9:39 am

Have you checked your fuel tank and fuel strainer for dirt and debris? IF the rest of the fuel system is clean, your problems may be the result of using ethanol enhanced fuel with the rubber tipped float needle. I would contact Zenith to determine if their rubber compound is suitable for use with ethanol. While on the phone with them, I would see if an all-metal needle is available.

BTW, which model Zenith did you use? I may want to replace mine someday.
Last edited by Don McCombs on Tue Dec 11, 2012 1:26 pm, edited 1 time in total.
Don McCombs
MD, Deep Creek Lake

"1950 Something" Farmall Cub
1977 International Cub w/FH
1978 International Cub
1948 Farmall Super A
1951 Farmall Super C w/FH
User avatar
Don McCombs
Team Cub Mentor
Team Cub Mentor
 
Posts: 10532
Joined: Mon Feb 03, 2003 6:45 am
Location: MD, Deep Creek Lake
Zip Code: 21550
Tractors Owned: "1950 Something" Farmall Cub
1977 International Cub w/FH
1978 International Cub
1948 Farmall Super A
1951 Farmall Super C w/FH
Circle of Safety Award
Circle of Safety: Y

Re: Carb Weeping and Choke when Warm

Postby Bus Driver » Tue Dec 11, 2012 11:12 am

The need for the choke could be a partially clogged high speed jet.
Luck favors those who are prepared
User avatar
Bus Driver
Team Cub Mentor
Team Cub Mentor
 
Posts: 2650
Joined: Sat Feb 11, 2006 5:26 pm
Location: NC

Re: Carb Weeping and Choke when Warm

Postby Ironlegs » Wed Dec 12, 2012 8:07 am

If my memory serves me correctly, my replacement Zenith carb for my Super A was a model 161. The people at Zenith are helpful with identifying the correct model...their website is all about carbs for more modern applications/vehicles.

On the questions about a clean fuel system, I checked the fuel strainer screen and found it clean...and re-cleaned it anyway. I think I may have a fuel gumming situation in the float valve seat with the rubber-tipped plunger. I think the weeping of fuel I'm experiencing is closely related to the performance problem. I'm left to "try this and try that" to find the problem and remedy it unless one of the forum members can direct me.
Ironlegs John
Ironlegs
Cub Star
Cub Star
 
Posts: 80
Joined: Tue Aug 21, 2012 10:21 am
Location: McKean PA
Zip Code: 16426
Tractors Owned: 1951 Farmall Super A
1958 Farmall Cub
Circle of Safety Award
Circle of Safety: Y

Re: Carb Weeping and Choke when Warm

Postby Don McCombs » Wed Dec 12, 2012 9:23 am

How about the interior condition of the fuel tank? How old is the fuel in the tank? If you suspect varnish deposits may be the culprit, I would drain the tank (if the fuel is older than 90 days) and try some Seafoam in the new fuel according to the label directions.
Don McCombs
MD, Deep Creek Lake

"1950 Something" Farmall Cub
1977 International Cub w/FH
1978 International Cub
1948 Farmall Super A
1951 Farmall Super C w/FH
User avatar
Don McCombs
Team Cub Mentor
Team Cub Mentor
 
Posts: 10532
Joined: Mon Feb 03, 2003 6:45 am
Location: MD, Deep Creek Lake
Zip Code: 21550
Tractors Owned: "1950 Something" Farmall Cub
1977 International Cub w/FH
1978 International Cub
1948 Farmall Super A
1951 Farmall Super C w/FH
Circle of Safety Award
Circle of Safety: Y

Re: Carb Weeping and Choke when Warm

Postby Eugene » Wed Dec 12, 2012 11:34 am

Ironlegs wrote:I think I may have a fuel gumming situation in the float valve seat with the rubber-tipped plunger.
When shutting down for the day, shut off the fuel at the tank and let engine die of fuel starvation. This will let the carburetor float drop and open the needle valve.

Don McCombs wrote:I would drain the tank (if the fuel is older than 90 days) and try some Seafoam in the new fuel according to the label directions.
Works some times and well worth a try. Drain the entire fuel system including the carburetor bowl. Install a small container of fuel system cleaner to fuel tank. Put two gallons of fresh gasoline in gas tank. Open fuel shut off. Let set for 5 or 10 minutes. Start engine.
I have an excuse. CRS.
Eugene
Team Cub Mentor
Team Cub Mentor
 
Posts: 12495
Joined: Fri Jul 02, 2004 9:52 pm
Location: Mo. Linn
Zip Code: 65051
Circle of Safety Award
Circle of Safety: Y

Re: Carb Weeping and Choke when Warm

Postby Ironlegs » Thu Dec 13, 2012 11:36 am

The fuel tank is in fine shape...no corrosion. I screen all fuel at the time of each fill. I shut off the fuel strainer cock after each use of the machine. I guess my next move is to remove the carb and open it up (again) to search for debris or gum. The fuel in this machine never gets older than about a month. I use about 125 gallons per year in this machine.
Ironlegs John
Ironlegs
Cub Star
Cub Star
 
Posts: 80
Joined: Tue Aug 21, 2012 10:21 am
Location: McKean PA
Zip Code: 16426
Tractors Owned: 1951 Farmall Super A
1958 Farmall Cub
Circle of Safety Award
Circle of Safety: Y

Re: Carb Weeping and Choke when Warm

Postby Ironlegs » Tue Dec 18, 2012 10:25 am

Fellows, I have a verdict on my problem with having to choke the carburetor, even with a warm engine, and a weeping carb fuel bowl after stopping the ignition (fuel cock on). I found a piece of the paper/cardboard orifice gasket for the carb's main jet stuck immediately down-stream of the fuel bowl's outlet to the main jet. The carburetor model is Zenith (161, I believe) and was purchased new about 18 months ago. After a full carb disassembly, cleaning and removal of the card board piece, the tractor runs great (again). In place of the damaged washer, I used Permatex and an o-ring...there was no way I was going to take a chance on another paper/cardboard washer. Case solved.
Ironlegs John
Ironlegs
Cub Star
Cub Star
 
Posts: 80
Joined: Tue Aug 21, 2012 10:21 am
Location: McKean PA
Zip Code: 16426
Tractors Owned: 1951 Farmall Super A
1958 Farmall Cub
Circle of Safety Award
Circle of Safety: Y


Return to Farmall A, Super A, AV

Who is online

Users browsing this forum: jpcubs and 2 guests