Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 07-15-2020, 05:18 PM   #1
sofield
Member
 
Join Date: Aug 2013
Location: Long Island NY
Posts: 72
Default Model “A” Bucking at 45 mph plus

Model “A” Bucking at 45 mph plus
The car is a “A” with indented firewall with a “B” engine, “A” head, converted to 12V, running a “B” carb and “B” distributor, 3.0-ohm coil, new condenser, cleaned points and replaced inline gas filter. The car idles well and runs well up to 42-44 mph. As speed is gradually increased to 50-55 mph the engine starts bucking and will to continue to buck until the speed is decreased to 42-45 mph again and then run well. The car has been driven 25 + miles at one time during the same day with the same response each time. A response to a solution from the members of the Ford barn membership is appreciated.
Sofield
sofield is offline   Reply With Quote
Old 07-15-2020, 06:02 PM   #2
Jacksonlll
Senior Member
 
Jacksonlll's Avatar
 
Join Date: Jul 2012
Location: Michigan-- Member of Oakleaf of MARC
Posts: 1,686
Send a message via ICQ to Jacksonlll
Default Re: Model “A” Bucking at 45 mph plus

Not getting enough fuel into the carb bowl. I don’t know about B carbs, but if it’s like the zenith, your fuel line might be pressing against the screen in the carb.
Jacksonlll is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 07-15-2020, 06:27 PM   #3
WHN
Senior Member
 
Join Date: Mar 2017
Location: Connecticut Shoreline
Posts: 1,815
Default Re: Model “A” Bucking at 45 mph plus

Fuel problem.

I might start by takings apart and cleaning the carburetor. Check fuel lines and also the gas cap. Is there a air cleaner? If so, is it clean?

I think it’s something on the fuel/air side of you engine.

Enjoy.
WHN is offline   Reply With Quote
Old 07-15-2020, 06:43 PM   #4
Patrick L.
Senior Member
 
Patrick L.'s Avatar
 
Join Date: May 2010
Location: Largo Florida
Posts: 7,225
Default Re: Model “A” Bucking at 45 mph plus

Yep, sounds like fuel starvation. Try loosening the fuel cap, may be a vent issue. At least its an easy first thing to try.
Patrick L. is offline   Reply With Quote
Old 07-15-2020, 07:19 PM   #5
Mulletwagon
Senior Member
 
Mulletwagon's Avatar
 
Join Date: Jan 2019
Location: Florida Panhandle
Posts: 585
Default Re: Model “A” Bucking at 45 mph plus

Does the shutoff valve on an indented firewall have a pencil filter like the earlier models ? If so, worth checking. Does sound like fuel starvation.
Mulletwagon is offline   Reply With Quote
Old 07-15-2020, 10:13 PM   #6
Johnny Nitro
Member
 
Johnny Nitro's Avatar
 
Join Date: Apr 2012
Posts: 63
Default Re: Model “A” Bucking at 45 mph plus

Sponsored Links (Register now to hide all advertisements)
Are you using gravity fed fuel, or the “B” engine’s fuel pump?
Johnny Nitro is offline   Reply With Quote
Old 07-16-2020, 05:47 AM   #7
bavArian
Senior Member
 
bavArian's Avatar
 
Join Date: Sep 2019
Location: Germany
Posts: 215
Default Re: Model “A” Bucking at 45 mph plus

If it's a fuel problem I guess it should happen in 1st and 2nd gear as well if you reach high rpms, you could check that.
bavArian is offline   Reply With Quote
Old 07-16-2020, 09:54 AM   #8
Ernie Vitucci
Senior Member
 
Join Date: May 2016
Location: Scottsdale, Arizona
Posts: 611
Default Re: Model “A” Bucking at 45 mph plus

Good Morning...Just a thought, but check your point gap...Your rubbing block might have worn down a bit and your points are closer than 0.018. Could also be a sign of a coil that is a bit long in the tooth...same with your condenser. Ernie in Arizona
Ernie Vitucci is offline   Reply With Quote
Old 07-16-2020, 09:55 AM   #9
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 8,099
Default Re: Model “A” Bucking at 45 mph plus

I would check float height in the carburetor , Five eights is the correct float setting . If the float setting is too low , the engine will starve for gas at higher speed .
Purdy Swoft is offline   Reply With Quote
Old 07-16-2020, 11:58 AM   #10
Planojc
Senior Member
 
Planojc's Avatar
 
Join Date: May 2010
Location: Plano, Texas
Posts: 828
Default Re: Model “A” Bucking at 45 mph plus

Agree float height.
Planojc is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 04:58 AM.