Tillotson Model X

Installation

1. Prepare the manifold

After removing the old carburetor, make sure the manifold flange is clean and smooth.

2. Install the carburetor

Install the Tillotson Model X using a new flange gasket. The hookup and installation are the same as for the original carburetor.

Flush the fuel line

Before connecting the fuel line, flush it thoroughly. Bending and handling an older fuel line can loosen internal scale and debris.

Fuel contamination is a common cause of carburetor leakage. Make sure an effective fuel strainer is installed ahead of the carburetor.

Engine Preparation

Satisfactory carburetor performance depends on a properly conditioned engine. Before making final carburetor adjustments, check the following:

• Clean the spark plugs and set the gaps to .035 inch.
• Inspect the breaker points for pitting or high spots and set the point gap between .018 inch and .022 inch.
• Check engine compression by turning the engine over slowly with the starting crank. Each cylinder should provide strong, reasonably uniform compression.

If compression is noticeably uneven, inspect the valves and piston rings.

Adjustment

1. Low-speed adjustment: Before starting the engine, gently close the low-speed adjustment to its seat, then open it 3/4 turn.
2. High-speed adjustment: Close the dash (high-speed) adjustment, then open it one full turn.
3. Warm the engine: Start the engine and allow it to run at these settings until thoroughly warm.
4. Prepare for idle adjustment: Close the throttle and fully retard the spark.
5. Set the low-speed mixture: Very slowly turn the low-speed (idle) thumb screw to the left, or outward, until the engine begins to flutter or miss. Then turn it to the right until the engine fires evenly.
6. Set the high-speed mixture: With the engine warm, the normal running position is approximately 1/8 to 1/4 turn open. Drive at about 25 mph with the spark advanced and adjust to the point where the engine runs smoothly without missing or the car surging.

Do not adjust the mixture so lean that the engine misses or the car surges. The original instructions note that no mileage or economy advantage is gained by doing so.

Fuel Level

Remove the carburetor upper body containing the float mechanism and turn it upside down. The float should be parallel with the cover.

If adjustment is necessary, carefully bend the float to obtain a distance of 1 inch from the gasket flange to the lower edge of the bead around the middle of the float.

Service Hints

Gasoline leaking from the carburetor air horn is generally attributed in these instructions to dirt-related inlet needle and seat problems, or to a loose main nozzle or nozzle gasket.

1. Separate the upper and lower carburetor bodies.
2. Remove the inlet needle and seat and clean them thoroughly with compressed air.
3. Lightly tap the inlet needle against the seat while turning it several times to reseat it.
4. Remove deposits of dirt, water, and other contamination before reassembly.
5. Remove the main nozzle using a screwdriver with smooth edges to avoid damaging the casting threads.
6. Make sure the nozzle gasket seats correctly in its channel and is neither wrinkled nor cracked.
7. Reassemble the carburetor and make sure the nozzle is secure in the casting.