The Ford Barn

Laredo · 08-19-2022, 05:09 PM

Is it normal for a Tillotson float arm to wear/create a dimple from the needle valve so quickly?

The carb was recently rebuilt on this Model A that I bought a few weeks ago. After getting it home, it started dumping gas from the carburetor. I took it apart and found that the rebuilder set the float at 1-1/4" instead of 1", causing the float to drop so low that the needle valve dropped too far and put it in a bind. Wouldn't let the float come back up. The end of the needle valve that contacts the float arm had also put a decent dimple in the brass. I took some sandpaper and smoothed that whole area of the float arm to remove the dimple and reinstalled.

Now, I have the carb. off and apart because it's leaking at the gasket (housing is slightly warped). During disassembly, I noticed that a new dimple is already forming from the needle. Is this normal for it to form this quickly? (I have only put 5 miles at most on it since sanding it smooth.) Wouldn't this eventually wear through at this rate?

Herb Concord Ca · 08-19-2022, 06:48 PM

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I've rebuilt a number of Tillotsons over the years. The dimple doesn't look that bad or deep. I've seen and used worse. Check your float level again. Is it level across the length of the barrel? You also might want to get one of the site tubes the vendors sell, to check your fuel level in the bowl while the motor is running, that might show you something.

08-19-2022, 05:09 PM	#1
Laredo Member Join Date: Jan 2022 Location: Louisiana Posts: 40	normal wear on Tillotson float arm? Is it normal for a Tillotson float arm to wear/create a dimple from the needle valve so quickly? The carb was recently rebuilt on this Model A that I bought a few weeks ago. After getting it home, it started dumping gas from the carburetor. I took it apart and found that the rebuilder set the float at 1-1/4" instead of 1", causing the float to drop so low that the needle valve dropped too far and put it in a bind. Wouldn't let the float come back up. The end of the needle valve that contacts the float arm had also put a decent dimple in the brass. I took some sandpaper and smoothed that whole area of the float arm to remove the dimple and reinstalled. Now, I have the carb. off and apart because it's leaking at the gasket (housing is slightly warped). During disassembly, I noticed that a new dimple is already forming from the needle. Is this normal for it to form this quickly? (I have only put 5 miles at most on it since sanding it smooth.) Wouldn't this eventually wear through at this rate?

08-19-2022, 06:48 PM	#2
Herb Concord Ca Senior Member Join Date: May 2010 Location: Concord CA Posts: 638	Re: normal wear on Tillotson float arm? Sponsored Links (Register now to hide all advertisements) I've rebuilt a number of Tillotsons over the years. The dimple doesn't look that bad or deep. I've seen and used worse. Check your float level again. Is it level across the length of the barrel? You also might want to get one of the site tubes the vendors sell, to check your fuel level in the bowl while the motor is running, that might show you something.