Whistlin' Zenith

bobpo1

bobpo1

Senior Member
I just removed the Tilliston I had been running for a couple of years and replaced it with a "rebuilt" Zenith 1. After I got it started and adjusted to where I thought it should be I noticed that when I turn the engine off, the carb whistles. Now I know this isn't quite right but I don't know what causes it. Any ideas?

Also throttling the engine after it's warm and then backing off the throttle it pops a few times. This is all without an air cleaner. Again, any ideas appreciated.
 
The only "whistling" carb I have ever discovered had an air leak between the carb and the intake manifold. A new carb gasket silenced the whistle. Given the pops, it sounds like you may have a lean air mixture and further supports the suspicion of an air leak in the system. Could even be a manifold to block leak.
Good Day!
 
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Dave, you were right about the Exhaust Manifold, I check and ofund that all four (4) mounting bolts needed about a 1/4" turn. It seems to pretty much have eliminated the popping. Thanks for the info pertaining to that.

JD, are you referring to the Throttle Plate itself? Also how exactly did you correct the situation?

I am also still dealing with gasoline fumes. I can't seem to get to the bottom of this. I CANNOT find a leak or seepage anywhere. I've been over the tank bracket, the fuel bowl, the shut-off, all the line connections, etc.. My wife is extra sensitive to any kind of fumes and it actually gives her a headache to ride in the 'A'. I need her to ride along 'cause she has the money..........(an I ain't kiddin').... It's a situation that's worked pretty well for us for going on 55 years now.
 
Do you have gas fumes, or exhaust fumes?
If gas, does it aways have them, or only during the first minute after starting?

For the throttle plate to close completely you need to back off the screw on the side linkage that sets the idle speed, then see if the throttle plate fits the bore tight. If not, then loosen the two screws holding the plate and tap on the plate while holding the throttle closed. This should allow the plate to settle in to the bore nice and square so it is fully closed. Keep holding the throttle closed and tighten the two plate screws. Now you will need to set the RPM screw back to hold the plate slightly open.
 
Git yo' self a cheep Harbor Freight stethescope. Pop off the probe, & with jist the open hose, they're GREAT for finding vacuum or exhaust leaks, also, with just the open hose, they can help localize noise that seem to transmit EVERYWHERE when using the probe!----Bill W.
(CAUTION! DON'T ever stick the open hose on a vacuum fitting, IT'LL SUCK OUT YOU EARBALLS!!)
 
the throttle shafts get loosey goosey in the bore of the carb , sucks vacuum and whistles. also causes driveability problems, and erratic high idle.
the fix is an oversize throttle shaft,,,all the jobbers sell them
 
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Can't thank you guys enough, I'm working on Ms. Tillie as we speak. Taking her to the First Car Show of the season tomorrow. Weather is looking good and all proceeds go to children with health problems. Makes for a great combination.

And yes that gas fume problem is gettin' to me. It's present whenever it's running, but no leaks. I tightened the exhaust pipe to manifold and it's quieter in the engine compartment, but still the fumes.
 
Hmm! Ms. TILLIE, hmm, Duzit seem that cars with LADIE'S names are harder to UNDERSTAND & harder to FIX?? HMMM! I seem to get along better VERMIN than I did with MINERVA!! VERMIN will tell me WHUT'S WRONG, MINERVA would only say, "NUTHIN'S WRONG"!! And "ROLL" her "EYES"! Hate it whin women do that!---Bill W.
 
Check for a cracked manifold. I was getting fumes and when I had the ex. manifold off I found the crack on the back side.
Also plug off the vac.port for your wiper on the intake and see if the gas fumes go away.
 
Thanks guys for the help. Now I got a bigger one, the clutch pedal went to the floor right after a car show. Went it rains, it pours so they say. I found a fella who specializes in restoring and repairing these cars, so I figure I'll have him go over it thoroughly.
 
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Well, the Whistlin' Zenith problem has been solved.I bought the used carb from a local fella but I didn't go through it. I recently had to have some work done on Miss Tillie and the mechanic found that the gasket on the Zenith was slighly protruding out one side of the carb. New gasket and the whistle is gone. So are the gas fumes.... Amazing is all I can say. Live and Learn.
 
I was going to say check the venturi. A lot of venturii (plural) are not made correctly and "shuck" around in the recess where they are supposed to be a press fit.

I myself have rebuilt a Zenith and was forced to use a repop venturi - and was not pleased with the fit/form/can't say yet on function part on this Carb.

If you open it up and the venturi can drop out by gravity - then it's too loose and might cause a whistle.

Joe K
 
Bill Goddard said:
My venturi is loose enought to fall out on its own. Would a gasket sealer like permatex work here? Bill G
Click to expand...

It should. I put mine together counting on just the gasket to seal - after all, flow is "through" the venturi normally - and not around it.

I've not checked the operation of this carb though. I've considered just buying a better quality venturi - it should't be hard to measure the hole with an inside/outside micrometer and then call Snyder's (or someone) and have them confirm the fit.

On my list of things to do...

Joe K
 
I've never had a problem with a repro venturi, even if they are just slightly loose.
I bought a couple venturii from A&L and a couple from Bratton's.

Four more inches of rain last night and it's still coming down.
 
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