The Ford Barn

mll1446 · 09-29-2023, 05:24 PM

Put a new Tilotson carb on model a pickup and have to pull throttle lever half way down or more and will start and run but as soon as I pull lever up to lower speed car shuts off. Any ideas or help appreciated

Marshall V. Daut · 09-29-2023, 06:38 PM

Adjust the carb's idle screw inward to raise the idle. If you switched from a Zenith, you will also have to bend the accelerator linkage arm in order to reach full throttle. The carb now probably only has 3/4 throttle. This requirement is often overlooked when switching carburetor brands. Marshall

nkaminar · 09-30-2023, 06:56 AM

After adjusting the idle speed and if it still shuts down, check the idle fuel adjustment, and if that does not work, clean out the idle circuits. Also check to see that you do not have any air leaks at the flange or throttle shaft. Running the gas from an unlit propane torch over the areas should not make any difference in rpm.

The vendors sell an adjustable link for the throttle rod. It is advertised for the ignition rod but will work on the throttle rod. See https://www.snydersantiqueauto.com/p...9546&cat=41663

TMarsh · 09-30-2023, 03:38 PM

Marshall, you are the man or woman, I have about 5000 miles on my A I put together from buckets of parts. It runs great and I am proud of her. Had a Zenith and a friend of mine gave me a Tillotson and said Zenith was for show and Tillotson was for go. He said his 29 would run 58 with this carb. Mine ran just fine for me with the Tillotson. Checked today and I gained a quarter inch of throttle after I read your post and adjusted my linkage. Never new she could run so fast if needed. Thanks again.

Marshall V. Daut · 09-30-2023, 04:36 PM

TMarsh -
Hurray! Good for you! You're going to enjoy driving your Model A more now that you can use all 40 horsepower of the engine. Pretty zippy now, isn't it? I am convinced that many owners, who complain about lack of performance and top end, have a poorly-adjusted accelerator linkage. It's rare that you can simply swap carburetor brands and not need to make some kind of linkage adjustment.
Thanks for the report. It's nice to be right every once in a while.

Marshall, da MAN animal

mll1446 · 10-01-2023, 07:42 PM

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Thank you

Marshall V. Daut · 10-01-2023, 07:54 PM

By the way, to those who bend the accelerator linkage to achieve full throttle after changing carburetors, do NOT test results by manually revving up the engine using the linkage rod connected to the carb's throttle plate arm. Full throttle will deceivingly be reached every time doing it that way. You instead need to check travel by having a second person sit in the passenger's compartment and push the accelerator button to the floorboard as you watch the butterfly arm's travel and note whether it stops at the peg in the upper throttle body, which is full throttle. That reproduces real world usage.
Marshall

TMarsh · 10-02-2023, 07:49 AM

Marshall, you are correct it takes a person in the drivers seat to push on the accelerator to check for full throttle.

Marshall V. Daut · 10-02-2023, 09:40 AM

Probably the easiest two-man job required when working on a Model A. Tailor-made for a wife as the second person.

M.

mll1446 · 10-03-2023, 07:45 PM

Thank you all fixex

Patrick L. · 10-04-2023, 06:54 AM

All good suggestions. Have you tried adjusting the idle fuel mixture ?

09-29-2023, 05:24 PM	#1
mll1446 Senior Member Join Date: May 2010 Location: Palatine il Posts: 320	Tilotson carb question Put a new Tilotson carb on model a pickup and have to pull throttle lever half way down or more and will start and run but as soon as I pull lever up to lower speed car shuts off. Any ideas or help appreciated

09-29-2023, 06:38 PM	#2
Marshall V. Daut Senior Member Join Date: Apr 2011 Location: Davenport, Iowa Posts: 2,112	Re: Tilotson carb question Adjust the carb's idle screw inward to raise the idle. If you switched from a Zenith, you will also have to bend the accelerator linkage arm in order to reach full throttle. The carb now probably only has 3/4 throttle. This requirement is often overlooked when switching carburetor brands. Marshall

09-30-2023, 06:56 AM	#3
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,900	Re: Tilotson carb question After adjusting the idle speed and if it still shuts down, check the idle fuel adjustment, and if that does not work, clean out the idle circuits. Also check to see that you do not have any air leaks at the flange or throttle shaft. Running the gas from an unlit propane torch over the areas should not make any difference in rpm. The vendors sell an adjustable link for the throttle rod. It is advertised for the ignition rod but will work on the throttle rod. See https://www.snydersantiqueauto.com/p...9546&cat=41663 __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

09-30-2023, 03:38 PM	#4
TMarsh Senior Member Join Date: Jun 2019 Posts: 131	Re: Tilotson carb question Marshall, you are the man or woman, I have about 5000 miles on my A I put together from buckets of parts. It runs great and I am proud of her. Had a Zenith and a friend of mine gave me a Tillotson and said Zenith was for show and Tillotson was for go. He said his 29 would run 58 with this carb. Mine ran just fine for me with the Tillotson. Checked today and I gained a quarter inch of throttle after I read your post and adjusted my linkage. Never new she could run so fast if needed. Thanks again.

09-30-2023, 04:36 PM	#5
Marshall V. Daut Senior Member Join Date: Apr 2011 Location: Davenport, Iowa Posts: 2,112	Re: Tilotson carb question TMarsh - Hurray! Good for you! You're going to enjoy driving your Model A more now that you can use all 40 horsepower of the engine. Pretty zippy now, isn't it? I am convinced that many owners, who complain about lack of performance and top end, have a poorly-adjusted accelerator linkage. It's rare that you can simply swap carburetor brands and not need to make some kind of linkage adjustment. Thanks for the report. It's nice to be right every once in a while. Marshall, da MAN animal

10-01-2023, 07:42 PM	#6
mll1446 Senior Member Join Date: May 2010 Location: Palatine il Posts: 320	Re: Tilotson carb question Sponsored Links (Register now to hide all advertisements) Thank you

10-01-2023, 07:54 PM	#7
Marshall V. Daut Senior Member Join Date: Apr 2011 Location: Davenport, Iowa Posts: 2,112	Re: Tilotson carb question By the way, to those who bend the accelerator linkage to achieve full throttle after changing carburetors, do NOT test results by manually revving up the engine using the linkage rod connected to the carb's throttle plate arm. Full throttle will deceivingly be reached every time doing it that way. You instead need to check travel by having a second person sit in the passenger's compartment and push the accelerator button to the floorboard as you watch the butterfly arm's travel and note whether it stops at the peg in the upper throttle body, which is full throttle. That reproduces real world usage. Marshall

10-02-2023, 07:49 AM	#8
TMarsh Senior Member Join Date: Jun 2019 Posts: 131	Re: Tilotson carb question Marshall, you are correct it takes a person in the drivers seat to push on the accelerator to check for full throttle.

10-02-2023, 09:40 AM	#9
Marshall V. Daut Senior Member Join Date: Apr 2011 Location: Davenport, Iowa Posts: 2,112	Re: Tilotson carb question Probably the easiest two-man job required when working on a Model A. Tailor-made for a wife as the second person. M.

10-03-2023, 07:45 PM	#10
mll1446 Senior Member Join Date: May 2010 Location: Palatine il Posts: 320	Re: Tilotson carb question Thank you all fixex

10-04-2023, 06:54 AM	#11
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Tilotson carb question All good suggestions. Have you tried adjusting the idle fuel mixture ?