The Ford Barn

jlsmith80 · 07-07-2014, 10:22 PM

I inherited my grandpas 1930 model a. I was driving it the other day and twice when I shut it off it backfired. I moved the spark lever all the way up like he always did for starting and shutting down. But then later notice the throttle lever was about a 1/3 of the way down. Do you think that is what caused it to backfire. I was thinking it had too much fuel. Should I move the throttle lever all the way up when shutting it down so it won't backfire. When I park it for long periods I always turn gas off and let it use up gas in carb and it never backfires.

tbirdtbird · 07-07-2014, 10:27 PM

backfiring is usually from not enough fuel.
open the GAV on the dash 1/4 turn and try it. You can never be wrong playing with the GAV

Mitch//pa · 07-07-2014, 10:29 PM

the throttle lever should be all the way up at all times except for starting mainly cold starts. i would obtain a copy of the model A owners manual for basic start and driving operations....

jlsmith80 · 07-07-2014, 10:45 PM

But do you think having the throttle down when shutting off could have caused it

tbirdtbird · 07-08-2014, 12:01 AM

maybe. make sure the lever is up next time and see what happens

Join the local club and get someone to help you become familiar with the car

Tom Wesenberg · 07-08-2014, 12:34 AM

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Quote:

Originally Posted by jlsmith80

But do you think having the throttle down when shutting off could have caused it

Yes, it sure could. As Mitch said, the hand throttle should only be used for starting the engine.

Will N · 07-08-2014, 09:34 AM

The hand throttle also comes in handy when you're starting off on a hill and you don't want to roll back. In those situations when you think you need three feet to run the car- one on the brake, one on the clutch and the other on the accelerator- you can use the hand throttle in place of that third foot! Just keep your foot on the brake and rev the engine somewhat with the hand throttle while letting up on the clutch. You'll feel when the clutch starts to grab, and then you can let off the brake and take off with no rolling backward.

The backfire could have been because it was racing a little with the hand throttle down when you shut it off. The engine might spin down a little longer than normal from the higher speed without any spark to ignite the fuel that continued to be pulled into the cylinders, and the unburned fuel could ignite when it was pushed out into the hot exhaust manifold. Like tbirdtbird said, it's simple enough to test- next time make sure the throttle is all the way up when you shut it down.

johnbuckley · 07-08-2014, 10:25 AM

Gosh, I am the only one who drives regularly utilizing the hand throttle? I find the foot throttle not sensitive enough and too little travel from idle to full power. Thus I use the handthrottle most of the time even with LHD As with conventional pedal arrangement and always with RHD As with central throttle pedal! - Generally I drive with my right foot hovering over the brake pedal.

07-07-2014, 10:22 PM	#1
jlsmith80 Junior Member Join Date: Jun 2013 Posts: 13	Backfire I inherited my grandpas 1930 model a. I was driving it the other day and twice when I shut it off it backfired. I moved the spark lever all the way up like he always did for starting and shutting down. But then later notice the throttle lever was about a 1/3 of the way down. Do you think that is what caused it to backfire. I was thinking it had too much fuel. Should I move the throttle lever all the way up when shutting it down so it won't backfire. When I park it for long periods I always turn gas off and let it use up gas in carb and it never backfires.

07-07-2014, 10:27 PM	#2
tbirdtbird BANNED Join Date: May 2012 Location: inside your RAM Posts: 3,134	Re: Backfire backfiring is usually from not enough fuel. open the GAV on the dash 1/4 turn and try it. You can never be wrong playing with the GAV __________________ '31 180A

07-07-2014, 10:29 PM	#3
Mitch//pa BANNED Join Date: May 2010 Location: Bucks County, PA Posts: 11,454	Re: Backfire the throttle lever should be all the way up at all times except for starting mainly cold starts. i would obtain a copy of the model A owners manual for basic start and driving operations....

07-07-2014, 10:45 PM	#4
jlsmith80 Junior Member Join Date: Jun 2013 Posts: 13	Re: Backfire But do you think having the throttle down when shutting off could have caused it

07-08-2014, 12:01 AM	#5
tbirdtbird BANNED Join Date: May 2012 Location: inside your RAM Posts: 3,134	Re: Backfire maybe. make sure the lever is up next time and see what happens Join the local club and get someone to help you become familiar with the car __________________ '31 180A

07-08-2014, 09:34 AM	#7
Will N Senior Member Join Date: Jul 2010 Location: Pennsylvania Posts: 1,251	Re: Backfire The hand throttle also comes in handy when you're starting off on a hill and you don't want to roll back. In those situations when you think you need three feet to run the car- one on the brake, one on the clutch and the other on the accelerator- you can use the hand throttle in place of that third foot! Just keep your foot on the brake and rev the engine somewhat with the hand throttle while letting up on the clutch. You'll feel when the clutch starts to grab, and then you can let off the brake and take off with no rolling backward. The backfire could have been because it was racing a little with the hand throttle down when you shut it off. The engine might spin down a little longer than normal from the higher speed without any spark to ignite the fuel that continued to be pulled into the cylinders, and the unburned fuel could ignite when it was pushed out into the hot exhaust manifold. Like tbirdtbird said, it's simple enough to test- next time make sure the throttle is all the way up when you shut it down.

07-08-2014, 10:25 AM	#8
johnbuckley Senior Member Join Date: Jul 2010 Location: United Kingdom Posts: 1,559	Re: Backfire Gosh, I am the only one who drives regularly utilizing the hand throttle? I find the foot throttle not sensitive enough and too little travel from idle to full power. Thus I use the handthrottle most of the time even with LHD As with conventional pedal arrangement and always with RHD As with central throttle pedal! - Generally I drive with my right foot hovering over the brake pedal.