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dokks6t9

1940 Olds

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Hello all. I just put my 1940 Olds on the road today, and have a small problem, and a question about gas. First the easy one. Should I use leaded gas in her, or will regular, unleaded gas work as well??? Now for the harder one. She just doesn't like to start when hot. It's not a heat-soak problem with the starter, but one that deals with the carb. It will flood when it sits. I popped off the air cleaner and noticed gas still dripping into the throat of the carb, (carter carb).This goes on for quite a few minutes. To start the car, you must depress the gas pedal all the way to the floor. This is not right as we all know, and my question is what is making the gas squirt down the throat, causing a flooded condition? Float level? The gas is coming out of the squirter in the throat.Thanks in advance....

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The scare about using unleaded gas seems to have been somewhat overblown. One of the higher priced gasolines before the unleaded era was sold by Amoco, which bragged of having no lead. A lot will depend on your use of the car. For casual driving such as most antique cars receive, I doubt if there would be a problem, but leaded gas would be a no-brainer any way if you can obtain it. There are also additives which claim to protect. As for fixes, some owners install hardened valve seat inserts and stainless valves when rebuilding. However, there have been cases where the seats didn't stay put, so a competent machinist is a must.

Flooding results when gas is going through the needle and seat valve in excess quantities and the revs, if any, aren't high enough to gobble the fuel. That can be caused by too high a float level as you suggest. It will also result from contamination such as grains of rust in the fuel that prevents the needle and seat valve from seating properly, or just a bad needle and seat. It could also be percolating if the carb isn't sufficiently insulated from the manifold, and excess fuel pump pressure could cause it too. It appears that the car may have been dormant for a while, and if that is so, I would siggest you inspect the fuel filter if it has one, looking for contamination. Any hint of it leads to a need to look for contamination inside the carb's float chamber. Hate to discourage you, but this could lead to having the tank removed, cleaned and sealed. Good luck in finding ther right cure.

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Your car was built before the heavily leaded gas of the fifties and sixties. It was made to run on low octane, low lead or no lead gas.

The lowest octane unleaded will be fine. Do not use high octane, it will run better on low octane.

The flooding problem sounds like a worn needle valve or leaky float. Your carb is probably due for a rebuild.

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Thanks to the both of you for your great responses. I truly appreciate the help. Now does anyone know of a good source for a rebuild kit?? This car sat only through the winter months. It had a full tank of gas when put away. I think the seats and/or the float could be the problem. I'm going to see a buddy in about an hour to discuss.

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She just doesn't like to start when hot. It's not a heat-soak problem with the starter, but one that deals with the carb. It will flood when it sits. I popped off the air cleaner and noticed gas still dripping into the throat of the carb, (carter carb).This goes on for quite a few minutes. To start the car, you must depress the gas pedal all the way to the floor. This is not right as we all know, and my question is what is making the gas squirt down the throat, causing a flooded condition? Float level? The gas is coming out of the squirter in the throat.Thanks in advance....

It's not completely clear from your post, but I assume when you removed the air cleaner and observed the dripping gas the car was not running. This is classic, low-level fuel percolation.

Gasoline boils at a much lower temperature today than it did 15 years ago or more. As a result, even relatively moderate amounts of heat (as low as 90 degrees F) will cause the lighter molecules in gasoline to begin to vaporize. Any heat above 150 degrees will boil the gas completely dry. This causes an expansion that, due to the one-way check valves in the fuel pump, only has one way to go. The gas will boil/expand inside the fuel line and carburetor bowl until it finds a place to exit, in your case the venturi.

No amount of rebuilding or tuning will stop this, and all gasoline suitable for fuel injected cars will do the same thing. I went through about a half-dozen fuel pumps and carbs (including professionally rebuilt NOS versions of each) on a 1960 Buick chasing this problem. Unchecked it will at best only dilute the crankcase oil with whatever finds it's way past the rings at shut-off, and continue the hard hot start problem. At worst it will progress with increasing summer heat and/or begin oozing through pores & gaskets and dripping off of the carb, creating a real fire hazard. It got so bad on my 1960 Buick that I had to relocate the fuel line (away from the engine block) and go to a switched electric fuel pump. Otherwise I was dumping about 1/4 cup of raw gasoline right in & on top of my motor every time I shut it off hot. Those changes completely solved the problem.

Check your crankcase oil soon. I'd be willing to bet it's level is creeping up with gasoline thinning the oil out.

Edited by Dave@Moon (see edit history)

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You are correct Dave. I saw gas dripping in from the squirter while the engine was off. However, I did notice a few things wrong with the carb. It's a Carter WA-1..I took off the cover, and noticed the accelerator pump was leaking badly when I worked the throttle. That will be replaced. I also have the operators/service manuals on this car, and noticed the anti-percolator adjustment is way off. It states .005 to .015 is acceptable, but from what I can see, it's about .030. One of my local buds, who is approx in his 80's and works on hit & miss,antique tractors, and old flatties,declared it was a bad needle and seat, and/or a heavy float causing the problem. We'll have to wait and see.I'm going with the percolating problem, but all my gas lines are far away from the motor.THANK YOU for your great response!!!! By the way, the car does run like crap, and everything so far seems to say a rebuild couldn't hurt it. It runs smooth at speed,35-45, but to get there, it takes a light foot. I think that's where the faulty accel pump comes into play. The carb comes off this weekend and it should be back on Monday. I'll post a note as to progress. Thanks again...Loren

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Dave hit it: percolation.

The WA-1 Carter is supposed to have a little valve-cap on top of the float-bowl that opens-up when the throttle returns to the closed position: this the "anti-percolation" vent. Make sure that it is open when the throttle is closed against the idle-stop screw, and that it closes when the throttle is opened.

Also make sure the anti-perc vent passage to the float bowl is clear - it's the sort of place that insects love to build egg-cases in.

Additionally, the Carter WA-1 has a metering rod that needs to be properly adjusted for peak performance / economy.

If the carb has not been serviced recently, the leather plunger on the accelrator pump is probably fossilized and that will contribute to lousy acceleration (making you "feather the gas")...

Good luck !

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Hello dokks6t9, I agree to not worry about the unleaded gas.

On the carb, we have one of the top carb men in the country right here on the forum. For your parts check THE CARBURETOR SHOP . Good luck, Todd

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Dok

If it is a perculation problem due to the modern gasoline formulation, is there a insulating spacer between the carb and the manifold? If not, installation of a non-metalic spacer might help. The Carburetor Shop should be able to help you with a rebuild kit and a spacer.

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First off, THANK YOU ALL for the great responses!!! There sure is a bunch of great people here!!! This is my plan of attack. Carb will get a much needed rebuild. Accle. pump to be replaced. Anti-per cap and linkage to be adjusted. I've also considered putting in a in-line fuel filter, and isolating/insulating/moving the gas lines in the engine compartment. I was thinking of using "header wrap" on the gas lines. I do know two things are for sure....1. The accle. pump is bad...2. The anti-perculalor cap/linkage is totally out of adjustment. Again thanks to everyone. You guys/gals are truly super...:) I have a rebuild kit that came with car. I also have the Carb Shop now in my favorites!!!

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Desoto Frank, I have family in the Hazelton/Freeland area. Mom and Dad were born there, and moved to NY after the Second World War.

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The rebuilt carb went on the car today, and it looks like I got lucky. Accelerator pump was changed, new balls added, new gaskets, needle and seat replaced, and float adjusted.Before priming the carb, I adjusted the anti-percolator linkage which was not working before. Car stated without priming the carb, and seemed to run smooth once it warmed up abit. I ran the car hard and got it up to temperature, and then parked it. I popped the air cleaner off and wow, no gas coming from the venturi!!! Before it was just oozing in, and flooding the engine. Looks like all the rebuilding and ultimately, I believe, adjusting the anti-perc cap was the culprit.Now the garage doesn't have gas fumes coming into the house, and I can sleep better knowing the oil isn't going to be diluted down with gas. Tomorrow will be the acid test as the car will be getting inspected, and will be shut down for awhile for the inspection, but I believe things are sorted out. Thanks for all the help guys; what a great forum to be associated with!!

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