Re: Don’s 1937 (120) 138CD Deluxe Touring Limo

Posted by Don B On 2024/4/22 18:21:56

I’m revisiting my carburetor issue where the following happens…

About two to three minutes AFTER I shut off the car, I get fuel bubbling out around the accelerator shaft. The fuel is NOT boiling out…it’s not hot to the touch.

So, I called Daytona Parts to talk to them about getting a rebuild kit or having them rebuild. I spoke with Tim and he was SUPER helpful and spent some time with me to talk through what is happening and what may be needed.

When I described what was happening, he asked if my fuel pump had been rebuilt recently. It has been. And, when I thought about it, this issue didn’t come about until after the fuel pump was rebuilt.

He said this issue is actually very common after fuel pumps are rebuilt and the first thing to try was to lower the fuel level in the bowl by adjusting the float.

Here is what he said happens and why… In short, he said the fuel level in the bowl is too high and I need to adjust the float. He said there is seal in the fuel pump valve that was originally phenolic/fiber materiel. He said this material didn’t make a great seal and residual pressure when the car was shut off would be relieved through this seal back to the pump. Then, he said that pumps that are rebuilt today use a rubber seal that creates a very good seal. Therefore, the pressure can only be relieved through the carburetor. Apparently, the reason it takes two or three minutes for this to start happening after the car is shut off is that it takes some time for the temperature to rise (no fan etc…) to cause the fuel to over flow. He said I could confirm this by removing the air cleaner and looking into the carburetor.

So, after a drive, I shut off the car and removed the air cleaner. At this point no fuel was bubbling out and no fuel was going into chambers. Then, about two minutes later, I saw fuel overflowing in the chambers and at that same time, I saw fuel bubbling out of the accelerator shaft.

So, I’ll trying adjusting the float level slightly. Time said to just make a very small adjustment and see if it improves and that it would be an iterative process.. The key is no large adjustments.

I’ll post a follow up once I work up the nerve to tackle yet another item I know little about. I love how much I’m learning along the way!