View topic - 1938 S5 Carburetor

1938 S5 Carburetor
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Author:  kimrosenkranz [ Sat Jun 18, 2016 4:35 pm ]
Post subject:  1938 S5 Carburetor

We bought a 1938 DeSoto Custom S5 6 cyl manual tran at Barrett Jackson in 2012. We cannot get the carburetor that came on it to idle, D6H2. We bought a used E6M1 and a kit but cannot get it to run either. Before we spend more money we want to know which one we should buy next. Our research shows E6P5 is the replacement for this model car. Is there an after market model that would work better? Or will the E6M1 with a new kit suffice? A dealer is trying to sell us a E6U2 NOS, will that work? Thank you. Kim in Washington state :?:

Author:  TimBowers [ Sat Jun 18, 2016 6:01 pm ]
Post subject:  Re: 1938 S5 Carburetor

Hi, Kim

Can you post a few more details about the symptoms you're experiencing and what steps you've already taken?


Author:  kimrosenkranz [ Sun Jun 19, 2016 12:36 am ]
Post subject:  Re: 1938 S5 Carburetor

We had it in a mechanics shop for 6 months, he rebuilt two carbs listed above but he couldn't get run at all, we gave him $750 and towed it back home. Next guy was 82 he rebuilt the carb with some of ours parts and some if his, it started and ran but would die each time he turned down the idle. He said the floats were wrong size for the 6cy. A third person said we had a leak in the manifold so we tore that apart and had it machined down put back on with new gaskets. Still dies when we turn down the idle. The forth guy set the points and timing. Running better but still dies when we turn down the idle. We can drive it but wants to die when we stop. We had the motor rebuilt and now have basically a mix of ethynal and unethynal gas. Thank you..,

Author:  BrentJacobsen [ Wed Jul 06, 2016 10:58 pm ]
Post subject:  Re: 1938 S5 Carburetor

Hi Kim.

I am relatively new to the club, but not to old Chrysler six-cylinder cars. I can suggest that if you have changed carburetors, and both exhibited the same condition, that the problem is not likely in the carburetor.

I suspect the mechanic who advised that you had a manifold leak might have been on the right path. It is just that the manifold to head interface is not the source of the leak. One leak point I have found is in the exhaust heat chamber area under the carburetor. I have seen both cracks and corrosion holes in this area. This will cause an exhaust leak into the intake that will prevent a stable idle. I'm not saying this is the case on your car, but it is a source that might have escaped consideration. A 1938 Desoto is a nice car. I hope you can enjoy it soon!

Author:  kimrosenkranz [ Thu Jul 07, 2016 1:39 am ]
Post subject:  Re: 1938 S5 Carburetor

Thanks for responding, we will change out the lower gasket, neglected it when we resurfaced the manifold.

Author:  BrentJacobsen [ Wed Jul 13, 2016 2:07 am ]
Post subject:  Re: 1938 S5 Carburetor

Hi Kim,

Just changing the gasket between the intake and exhaust manifolds might not be enough. The chamber under the carburetor is heated by exhaust gas to improve warm-up performance. If there is a crack or pinhole leak in this area, exhaust gas could leak from this chamber directly into the manifold. This might not cause a drive problem except at idle when manifold vacuum is high and airflow is low. The exhaust gas can be a significant part of the incoming air charge, and cause a very rough and erratic idle.

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