The Ford Barn

Lefthander1930 · 12-05-2015, 03:40 PM

Just tried to start, carb was leaking/weeping a little gas. Took it apart & clean everything, It there a float chart ? Thats the thing that I could see would cause a weep/leak if it was set wrong. Carb has ball check & not neddle & seat ??What is a good starting point for the idle mixture ? Also the view shows adjusting needle that on the choke shaft ??

Patrick L. · 12-05-2015, 05:14 PM

The Tilly is a simple and fine carburetor. As with most things they tend to have their quirks which need to be corrected.
These carburetors are famous for warping which can and needs to be corrected. They also need to be properly cleaned which sometimes can be a problem. The main nozzle can be a PITA to remove and sometimes needs to be drilled out and replaced. The venturi air bleeds need to be clean.
I just set/adjust float to be level. I think the spec is 15/16" without looking it up. The float arm tends to wear a dimple in it which needs to smoothened to keep float from hanging. Be careful bending the float to make sure it stays parallel.
As far as the float valve, I prefer the Grose style.
I would suggest getting a how-to book such as Bratton catalog #37461

JamesAC · 12-05-2015, 09:44 PM

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I assume the adjusting needle you are speaking of is that which is adjusted by turning the "choke knob" (Gas Adjusting Valve) in the car clockwise or counterclockwise? Yes, it's on the same mechanism that does the choking of the car. Pull the knob out and the car is choked, usually used only on cold engine start-up those first turns of the engine before it fires, then it is released, that is, the choke is opened as soon as the engine starts.

The carburetor running mixture adjustment is controlled, a rather neat feature in my view, by rotating the GAV (Gas Adjustment Valve, or choke knob) clockwise or counterclockwise. Rotating counterclockwise enriches the mixture and clockwise leans it out. My engine with its fresh engine rebuild and a new Tillotson Model X carburetor runs best about 1/2 or slightly less of a turn off of closed, i.e., turned counterclockwise off from being run down all the way clockwise. Incidentally, don't turn the GAV "hard" off in the clockwise direction or you could damage the seat on the needle valve inside the carburetor.

12-05-2015, 03:40 PM	#1
Lefthander1930 Senior Member Join Date: Nov 2015 Location: Roseville Ca. Posts: 176	Tillotson carb Model X Just tried to start, carb was leaking/weeping a little gas. Took it apart & clean everything, It there a float chart ? Thats the thing that I could see would cause a weep/leak if it was set wrong. Carb has ball check & not neddle & seat ??What is a good starting point for the idle mixture ? Also the view shows adjusting needle that on the choke shaft ??

12-05-2015, 05:14 PM	#2
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Tillotson carb Model X The Tilly is a simple and fine carburetor. As with most things they tend to have their quirks which need to be corrected. These carburetors are famous for warping which can and needs to be corrected. They also need to be properly cleaned which sometimes can be a problem. The main nozzle can be a PITA to remove and sometimes needs to be drilled out and replaced. The venturi air bleeds need to be clean. I just set/adjust float to be level. I think the spec is 15/16" without looking it up. The float arm tends to wear a dimple in it which needs to smoothened to keep float from hanging. Be careful bending the float to make sure it stays parallel. As far as the float valve, I prefer the Grose style. I would suggest getting a how-to book such as Bratton catalog #37461

12-05-2015, 09:44 PM	#3
JamesAC Junior Member Join Date: Nov 2015 Posts: 26	Re: Tillotson carb Model X Sponsored Links (Register now to hide all advertisements) I assume the adjusting needle you are speaking of is that which is adjusted by turning the "choke knob" (Gas Adjusting Valve) in the car clockwise or counterclockwise? Yes, it's on the same mechanism that does the choking of the car. Pull the knob out and the car is choked, usually used only on cold engine start-up those first turns of the engine before it fires, then it is released, that is, the choke is opened as soon as the engine starts. The carburetor running mixture adjustment is controlled, a rather neat feature in my view, by rotating the GAV (Gas Adjustment Valve, or choke knob) clockwise or counterclockwise. Rotating counterclockwise enriches the mixture and clockwise leans it out. My engine with its fresh engine rebuild and a new Tillotson Model X carburetor runs best about 1/2 or slightly less of a turn off of closed, i.e., turned counterclockwise off from being run down all the way clockwise. Incidentally, don't turn the GAV "hard" off in the clockwise direction or you could damage the seat on the needle valve inside the carburetor.