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'39 LZ Possible Carburator Problems ???


friscozephyr
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Hi Everyone,

Over the past several months I have done the following On my '39 LZ sedan:

Installed rebuilt distributor

New Voltage regulator

New ignition harness

new spark plug wires

new fuel pump and hose

rebuilt LZ carburator (the original one on the vehicle was some kind of Ford V8 or truck carburator0

new exhaust system(restored manifold, new gaskets, new pipes, hangers and muffler)

New plugs set to the correct gap (I used the champion plugs that are supposedly hotter than the original replacement plugs)

Rebuilt transmission

Checked the coil for good spark. However, coil was not replaced.

Checked terminal plate contacts for wear. Some wear on the terminals but seemed OK.

New ignition resistors.

Last September after doing all this work I took the car to a show and she ran beautifully. It was almost a miracle. Plenty of power. The engine could almost get up to about 70 MPH (I didn't dare go faster because of the vibration and the fact that the tire and tubes were old).

Since September of last year I have only taken the car out once. The engine ran smooth when it was idling in the garage. I drove it to local gas station to fill up. Again it ran smooth to the gas station. However, after I filled up the gas tank and drove away from the gas station the engine ran very rough, almost like it was chooking from not getting fuel. The engine stalled a few times when it was idling at a stop sign and was very difficult to start up again. There was also a loss of power. I do recall I had a similar problem prior to all the above mentioned work.

Since I have done so much ignition and fuel system work my guess is that sediment from the fuel tank is getting into the fuel line (due to adding fuel or just plane driving around) and maybe clogging the carburator jets. I have no fuel filter on the fuel line and the fuel tank is either original condition or was restored about 15-20 years ago.

The only other thing I can think of is that the coil not working conistently or maybe a problem with the intake manifold. As mentioned above the only items that I have not replaced are the terminal plates and coil.

Any suggestions from you other LZ owners on what to check for would be helpful and greatly appreciated. I feel this LZ is very close to running in excellent shape. I have missed several shows this summer since I was worried the car would not make the trip. It is a shame to keep such a beautiful vehicle locked up in my garage.

Best regards,

James in Brisbane, CA

PS. About two years ago this car and I were featured in a local newcast about an art-deco related event. In addition this car has been featured in an International Auto Magazine. I'll try to post photos in the near future.

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James, It could well be that you got a charge of "junk" on the gas fill up. I rather doubt anything big enough to clog the jets got in the carburetor but you can check for debis by removing the carburetor top and having a look-see in the bowl. More likely something got clogged in the long,1/4" fuel line from the tank. There is a screen in the fuel pump that also might have got clogged up. I suspect that you may end up having to remove the tank, clean and seal it if you find small particles in the fuel bowl of the carburetor or in the fuel pump screen. Blowing out the fuel line is only a temporary fix as any junk in the tank will eventualy find it's way back in.

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Hi. I know you have changed ignitionresistor, but the symptoms sounds to me, that the problem is still here.You can make an easy check.Drive the car till it starts cheating you,then bypass the resistor and see if it helps.Best regards Birger

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i've had the same symptoms before but on a flathead V8 and after changing everything you mentioned plugs, wires, cleaned the carb bowl ect. the problems was still there until finally i was told to change the CONDENSOR and i did and it started running fine once again. Hope this helps since i'm told there is not much difference between the V12 and V8 except for the size.

MIKE.

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James, while you are checking things look for "water". The problem occuring right after the fill-up could also indicate you got some water mixed in with the gas. This happens. If you detect or think you might have got some water in that fill-up there are products you can add to the fuel that will absorb water or you can carefully remove the drain plug on the tank let some drain out. The water is heavier than the gas so it will come out first. Kinda messy so you should have a large pan to catch the gas and be ready to immediately replace the plug.

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"Peecher"

Thanks for all you suggestions. I'll be busy over the next three weeks trying to isolate the problem based on all the suggestions. Personnally, I like working on this car rather than paying someone $110.00/hour to fix it.

I forgot to mentiion in my first post that I did install new condensors.

Thanks again for the great advice. I'll keep everyone posted on my progress. I hope to have the car ready for big event that will take place in mid-September.

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I had condenser problems......because i used different....not new condensers....a matched set from Earle Brown..made althe difference....i also against lots of old boy warning run straight 6 volts to coil.....no problem ever..but i dont leave ignition on by accident ever...if your carb is full of crap...your never gona solve your problem......do you know if trouble is fuel or spark??

jb

oHIo

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Hey anyone, can someone tell me the correct way to check the voltage at the coil and resistors. I have a spec sheet that has the wiring diagram and specs for the car. There is no votage spec for the coil connection. Do you check voltage at the coil,at the resistors? With the igntion on but engine not running? Thanks for any replies. George.

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George, there are 2 sets of points and they are never open at the same time. With the ignition "on" you can check the voltage at each terminal of the coil. If the points are "open" for the side you are checking the voltage will be 6+ volts depending on your battery. When the points "close" the voltage should read about 3-1/2 to 4 volts. You can check this easily by connecting a volt/ohm meter to each coil connection and slowy turn the engine over by hand using the fan. If your reading alternates between 6+ and 3-1/2 to 4 volts the resistors (on the firewall above the steering column)for the ignition are okay. Each side of the resistor is about 1/2 ohm if you crawl up under the dash to check. The "hot" wire from the ignition switch feeds the center of this dual resistor while the 2 separate coil wires attach one to the top and one to the bottom terminal.If you get a continous 6 volt reading the points may be burnt or the connection on the resistor is not correct. if you get a continous low voltage in the 3 to 4 volt range the points in the distributor may not be opening.

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