Tillotson MT series question


Buzz Bomb

New Member
Nov 13, 2008
I got everything together today, and wanted to check for any leaks between the tank and the carb, (tank, Tillotson fuel bowl, line, Tillotson MT series carb). The carb was supposed to be tested good. Anyway, I put a bit of gas in the tank, opened the bowl valve, let the fuel fill the float chamber, and a minute later fuel ran out of the barrel(venturi) and onto the garage floor in a fast drip. Somebody said that this is normal. Bad needle valve in the float chamber? That cant be right.
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Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
up north now
Tap the chamber, sometimes the float may stick.

Other than that, the tip of the fuel shut off needle could have crud in it, or it's worn or bad.

Whizzer Nut

New Member
Dec 21, 2008
Millersburg Pennsylvania
I have the same set up. (46 H with Tillotson & glass fuel bowl) I can let the fuel turned on for days & it will not leak. I would think the needle & seat is sticking, dirty, or float problem. Float height may need to be set. Theese carbs are as simple as it gets, so it should be an easy fix. I would start with cleaning carb bowl & needle & seat. Good luck & keep Whizzin, Dan

If the needle valve & seat are good, and the float level is set correctly it shouldn't leak. I have however noticed a few leaking if the bike is tiltled to one side too much [using bike kick stand]. A friend of mine has a '47 with an "H" motor and we have messed with the float, replaced the seat and shut off [needle valve], and it always manages to leak on the kick stand, but never otherwise.

Have fun,