Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 11-30-2017, 12:44 PM   #1
skeazle
Senior Member
 
Join Date: Dec 2013
Location: Hershey, Pa.
Posts: 102
Default Leaky Zenith carb.

I got back from a nice easy ride in my 1930 Tudor sedan last week and the next day when I went out in the garage the smell of gas was over bearing. I looked underneath the car and there was a puddle of gas on the floor. Sure enough I noticed gas dripping from the carb. I tightened the bolt on the front by the bowl a little and I snugged up on both bolts on the bottom a little each. I thought that solved the problem but it still has a drip and I guess there is only one place left it can be at the big gasket that separates the two halves. Can I take the carb apart there just to put a new gasket on without disturbing anything else like jets and float etc.? It runs so good now and I would hate for it to get messed up by me tearing it apart. I just ordered a Zenith carb kit from Snyder's so I could get that big gasket. Yes I did shut the gas off when I parked it. Plus along with the gas leak there is an oil leak up front somewhere on the right side of the engine between the fan and the carb. I thought it might be that tube but the bolt wasn't loose on that. I checked the oil pan bolts and they were all snug. Any ideas? thanks, Jim
skeazle is offline   Reply With Quote
Old 11-30-2017, 12:49 PM   #2
oldforder
Senior Member
 
oldforder's Avatar
 
Join Date: Mar 2013
Location: Columbus Nebraska
Posts: 171
Default Re: Leaky Zenith carb.

If you are sure you shut the gas off when you parked it, then the shut off leaks. If it is shut off gas can't run out. Unless of course there is a hole in the bottom of the carb, and the gas from the carb bowl is all that ran out.
oldforder is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 11-30-2017, 01:21 PM   #3
ursus
Senior Member
 
Join Date: May 2010
Location: Oregon
Posts: 1,369
Default Re: Leaky Zenith carb.

I have found a few carbs that had hairline cracks that extended out from the main jet plug. They are nearly invisible to the eye but enough to allow a steady drip until the bowl is empty. Previous owners had overtightened the plug, a drip started from the resulting crack, so the tightened them some more, and the crack enlarged some more, etc.
ursus is offline   Reply With Quote
Old 11-30-2017, 02:04 PM   #4
skeazle
Senior Member
 
Join Date: Dec 2013
Location: Hershey, Pa.
Posts: 102
Default Re: Leaky Zenith carb.

I was out and started up the car and let it run for 10 minutes and no leaks. Then I decided to take the glass bowl off and drain that gas and when I put it back on and turned on the gas the bowl filled up like it should no leaks there but then I heard it running ou the bottom of the carb. I shut off the gas and held my mirror under the carb and sure enough the gas is leaking out of either the drain plug or the bolt next to it or both of them. I had just tightened the plug a little before I started it up. I'm thinking maybe the washer on the plugs are bad. That would be an easy fix. Can I get those at a parts place or hardware store? I hope it isn't a hairline crack. Jim
skeazle is offline   Reply With Quote
Old 11-30-2017, 02:40 PM   #5
Tom Endy
Senior Member
 
Tom Endy's Avatar
 
Join Date: May 2010
Location: Southern California
Posts: 3,122
Default Re: Leaky Zenith carb.

More than likely the leak is coming from the float valve not holding. Possibly some crud has gotten into the valve, or the valve is just worn. This will allow the level of fuel in the reservoir to rise. At the same time the level of fuel inside the main and cap jets will rise until they overflow. The fuel will then run down into the intake throat and run out through the small drain hole in the base of the throat. From there it runs back to the hex bolt of the drain plug under the main jet and drips off onto the ground.

Quite often this leads people to think the drain plug is leaking and they end up over tightening it and stripping out the threads.

Slide your finger into the throat under the choke butterfly all the way to the jets and see if it is wet in there. If so, the float valve is not holding.

My method of resolving the issue of a float valve that will not hold is to install a float valve with a Viton tip. I put these in all the Zeniths I rebuild.

Tom Endy
Tom Endy is offline   Reply With Quote
Old 11-30-2017, 02:59 PM   #6
skeazle
Senior Member
 
Join Date: Dec 2013
Location: Hershey, Pa.
Posts: 102
Default Re: Leaky Zenith carb.

Sponsored Links (Register now to hide all advertisements)
Tom, I took out the short drain plug and the washer is fine. So I put it back in and turned on the gas and gas started dripping from around those two plugs. Where should I stick my fingers in do you mean where the air filter is? I never had one of these apart so I'm a little dumb at it. If the float is sticking is it a major job replacing the float valve? I was hoping I wouldn't have to take off the carb and operate, it might turn out worse than what is was. Thanks for all the help, I will go back out there and tinker some more. Jim
skeazle is offline   Reply With Quote
Old 11-30-2017, 03:26 PM   #7
larrys40
Senior Member
 
Join Date: May 2010
Location: St Charles , Missouri
Posts: 1,994
Default Re: Leaky Zenith carb.

I ditto what tom said. If you put a finger or two inside the carb throat and it is whet the cap and main jets are being topped and fuel is running out them into the throat. This is because the needle and seat is probably not holding ( shutting off the full fuel flow) when closed.

As he said a good viton tip is probably the best solution. I have had some that don't work though... so I test them with a vacuum pump to make sure they hold vacuum prior to install. If it doesn't hold vacuum it probably won't hold fuel.

Review what Tom said and I have noted above and you should be able to rectify the problem.
Larry Shepard
larrys40 is offline   Reply With Quote
Old 11-30-2017, 03:29 PM   #8
skeazle
Senior Member
 
Join Date: Dec 2013
Location: Hershey, Pa.
Posts: 102
Default Re: Leaky Zenith carb.

Tom, I slid my finger in to the throat and there is some gas in there at least my finger tips came out with gas on them. What part # or description should I order and do I have to remove the carb( I would think I do) ? Is it a hard job? Jim
skeazle is offline   Reply With Quote
Old 11-30-2017, 03:47 PM   #9
Tom Endy
Senior Member
 
Tom Endy's Avatar
 
Join Date: May 2010
Location: Southern California
Posts: 3,122
Default Re: Leaky Zenith carb.

Bratton's Antique Auto 800-255-1929. Modern float valve P/N 14310, $15.25

A few year ago I bought several that did not work at all. I took them apart and found them full of brass machine chips. It was easy enough to clean them out. I called Walt Bratton and advised him about it. He is at the mercy of his supplier, but he got on his case and the situation improved. However, I still take them apart when purchased and I still occasionally find machine debris.

There is a small plastic washer that holds the needle in place. Use a very small screwdriver and pry it out. Check with a magnifying glass and a strong light, then clean it out. Press the washer back in making sure it Is even and does not restrict the valve.

Replacing the valve in a Zenith is not difficult. Best to remove it from the car. You will probably need two fiber washers under the valve, Do not molest the float as a means to adjust float level.

Tom Endy
Tom Endy is offline   Reply With Quote
Old 11-30-2017, 04:03 PM   #10
Synchro909
Senior Member
 
Synchro909's Avatar
 
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 7,471
Default Re: Leaky Zenith carb.

Guys, the OP also said he had turned off the fuel when the leak occurred. I agree it sounds like the float valve is faulty and replacement is the way to go. Clearly, the shut-off valve is also leaking. This is also an easy fix. I recommend: http://www.snydersantiqueauto.com/gas-valve-repair-kit
at $1.60, it is very cheap, easy to install and works well.
He also mentioned an oil leak and wondered about the return pipe leaking. I suggest taking the pipe off (2 small bolts) and inspecting the seals replace if necessary or use some permatex on both sides of them them before reinstalling.
__________________
I'm part of the only ever generation with an analogue childhood and a digital adulthood.
Synchro909 is offline   Reply With Quote
Old 11-30-2017, 04:27 PM   #11
BILL WILLIAMSON
Senior Member
 
BILL WILLIAMSON's Avatar
 
Join Date: Dec 2010
Location: FRESNO, CA
Posts: 12,560
Default Re: Leaky Zenith carb.

The float chamber vent is hidden on the backside of the carb, just above where the carb halves separate. Very likely your shut off valve leaks through, when supposedly "OFF"---
Go to modelabasics.com for good info & pics & animations.
Bill W.
__________________
"THE ASSISTANT GURU OF STUFF"
BILL WILLIAMSON is offline   Reply With Quote
Old 11-30-2017, 04:48 PM   #12
skeazle
Senior Member
 
Join Date: Dec 2013
Location: Hershey, Pa.
Posts: 102
Default Re: Leaky Zenith carb.

Thanks everyone for the help! I ordered a new viton fuel valve and a gasket kit. I ran the car for 10 minutes and shut off the shut off valve and it ran for a minute then shut off. So that has to be working but the glass bowl at the firewall was still full of fuel. I'm so confused! If the gas was turned off so that the car starved for gas then why wasn't the glass bowl dry also? Jim
skeazle is offline   Reply With Quote
Old 11-30-2017, 05:13 PM   #13
Big hammer
Senior Member
 
Join Date: Jun 2014
Location: Land of Lincoln
Posts: 3,114
Default Re: Leaky Zenith carb.

The glass sediment filter, fuel goes in at the top and fuel goes out at the top. Like a drinking glass if no water going in no water will go out, unless it's broken :-)
__________________
Don't force it with a little hammer tap, tap, tap
get a bigger hammer tap done
Big hammer is online now   Reply With Quote
Old 11-30-2017, 05:38 PM   #14
Synchro909
Senior Member
 
Synchro909's Avatar
 
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 7,471
Default Re: Leaky Zenith carb.

Quote:
Originally Posted by skeazle View Post
Thanks everyone for the help! I ordered a new viton fuel valve and a gasket kit. I ran the car for 10 minutes and shut off the shut off valve and it ran for a minute then shut off. So that has to be working but the glass bowl at the firewall was still full of fuel. I'm so confused! If the gas was turned off so that the car starved for gas then why wasn't the glass bowl dry also? Jim
The glass bowl stays full, even when you turn off the fuel and run the car till it stops. Your tank valve may be leaking enough to cause a pool on the floor but not enough to keep the motor running.
__________________
I'm part of the only ever generation with an analogue childhood and a digital adulthood.
Synchro909 is offline   Reply With Quote
Old 11-30-2017, 06:08 PM   #15
mhsprecher
Senior Member
 
mhsprecher's Avatar
 
Join Date: Aug 2012
Location: Takoma Park, MD
Posts: 2,811
Default Re: Leaky Zenith carb.

I have experienced the Viton valves sticking on both of my Model As. I removed them and replaced them with the old style valves. Just sharing my experience.
mhsprecher is offline   Reply With Quote
Old 12-01-2017, 01:52 PM   #16
skeazle
Senior Member
 
Join Date: Dec 2013
Location: Hershey, Pa.
Posts: 102
Default Re: Leaky Zenith carb.

Tom, I sent you a PM.
skeazle is offline   Reply With Quote
Old 12-01-2017, 02:15 PM   #17
skeazle
Senior Member
 
Join Date: Dec 2013
Location: Hershey, Pa.
Posts: 102
Default Re: Leaky Zenith carb.

So I just took off my carb and the gas line is dripping gas in the pan about a drop every 3 seconds or so. I assume that means that is a bad shut off valve. Should I assume that that was my problem all along or should I still take the carb apart and replace the float valve? So far I haven't disturbed the carb in anyway yet. I hope I don't everything looks brand new. Is replacing the shut off valve a major job? Jim
skeazle is offline   Reply With Quote
Old 12-01-2017, 04:04 PM   #18
Farrell In Vancouver
Senior Member
 
Farrell In Vancouver's Avatar
 
Join Date: May 2010
Location: Pitt Meadows BC
Posts: 1,003
Default Re: Leaky Zenith carb.

Like me you may fin both the shut off valve and the float needle by-passing. Start with the valve remove and replace or repair. then delve into the carb float needle.
Farrell In Vancouver is offline   Reply With Quote
Old 12-01-2017, 04:26 PM   #19
skeazle
Senior Member
 
Join Date: Dec 2013
Location: Hershey, Pa.
Posts: 102
Default Re: Leaky Zenith carb.

Thanks, Farrell I will do that. Jim
skeazle is offline   Reply With Quote
Old 12-01-2017, 04:50 PM   #20
Dick Steinkamp
Senior Member
 
Dick Steinkamp's Avatar
 
Join Date: Apr 2016
Location: Bellingham, WA
Posts: 1,163
Default Re: Leaky Zenith carb.

Jim,
If you have limited experience with Model As...or older cars in general, it is probably easier and less frustrating to replace both the carb and the shut off valve rather than taking the carb apart and rebuilding the shut off valve.

Separating the two halves of the carb can be frustrating and can result in a broken venturi or carb castings. While apart, you would normally completely disassemble it, soak it in carb cleaner, check the jets and passages for obstructions and damage, set the float height and reassemble it. This is not generally a job for a "rookie" although if you have some mechanical skills and an interest, learning can be a fun part of the hobby.

It would be easiest and more certain that you will have solved the carb leak problem if you buy a professionally rebuilt carb. I think they are about $200 from vendors like Bert's.

For the shut off valve, you will need to completely drain the tank. Then remove the valve, determine which one you have, and check to see if a rebuild kit is available for it. If it has been replaced by an aftermarket valve in the past, a kit is probably not available. Then you have to disassemble the valve, clean up the seating surfaces with fine grinding compound, repack it and reassemble it (and hope it still doesn't leak).

A new, reproduction of the original valve is $34 or so.

Before reinstalling the rebuilt old valve or a new one, I'd install the "pencil" micro filter on top of the valve to help insure "gunk" stays out of the carb.
__________________
All steel from pedal to wheel
Dick Steinkamp is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 03:39 AM.