The Ford Barn

johnbuckley · 07-05-2016, 10:56 AM

Friend sent me this B carb to check over ( it is fitted to a stock A engine with gravity feed tank) - All the symptoms he describes (stalling/stuttering when trying to power up hill etc )point to fuel starvation. Fuel level is 5/8 inch below gasket
No surge baffle with the float (has it been removed or are some like that?}Is the baffle essential?
Fow rates test out ( ml/min at 36 inch): main 88, cap 390, comp 158, power 35. Biggars book recommends, main 136-142, cap 372-462, comp 110-118, power 110-118. I don't want to take all the airway plugs out- the carb looks very clean. Apart from some of the jets being obviously way out are any other things I should be aware of?
IMG_1200.jpg

Chuck Sea/Tac · 07-05-2016, 11:41 AM

Your starving fuel because of a plugged main jet. Get them all to specs first. Check your throttle shaft for wear.

Jim Brierley · 07-05-2016, 11:58 AM

Also check the ignition, many carb are actually ignition problems.

tbirdtbird · 07-05-2016, 12:00 PM

has he opened the GAV more.....it is there to play with....many fuel starvation issues are because the GAV is turned in too far....don't be afraid of it

johnbuckley · 07-05-2016, 12:09 PM

Chuck Sea, the throttle shaft certainly has some play. I find the A carb is fairly forgiving with throttle shaft wear... But is it more critical on the B carb? Would this play cause lack of suction up the power jet, with the controlled port leaking?

Brian T · 07-05-2016, 12:51 PM

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I would get the main and power jet back to Biggars specs, and make sure the tube leading to the throttle shaft is clear, the B carb doesn't need the GAV after warmup which eliminates that, I don't believe the throttle shaft is a problem, should you need one they are now available

Ron in Quincy · 07-05-2016, 01:21 PM

Make sure the small hole in the throat or passage way , where the fuel from the pickup tube exits when the throttle is opened, is not plugged.

Ron

Jacksonlll · 07-05-2016, 02:18 PM

I don't know anything about a B carb, but if the fuel line goes in too far, like it can on an A carb, and hits the screen in the carb, this is exactly what happens. A little circumcision of the tube will fix it.

Ron in Quincy · 07-05-2016, 06:51 PM

The 32 B and 33-34 C passage ways and throat is no way like the Zenith- or Holley Carburetors that came on the A.

Ron

George Miller · 07-05-2016, 07:00 PM

check to see what color the spark is and how far it jumps.

07-05-2016, 10:56 AM	#1
johnbuckley Senior Member Join Date: Jul 2010 Location: United Kingdom Posts: 1,557	B carb fuel starvation Friend sent me this B carb to check over ( it is fitted to a stock A engine with gravity feed tank) - All the symptoms he describes (stalling/stuttering when trying to power up hill etc )point to fuel starvation. Fuel level is 5/8 inch below gasket No surge baffle with the float (has it been removed or are some like that?}Is the baffle essential? Fow rates test out ( ml/min at 36 inch): main 88, cap 390, comp 158, power 35. Biggars book recommends, main 136-142, cap 372-462, comp 110-118, power 110-118. I don't want to take all the airway plugs out- the carb looks very clean. Apart from some of the jets being obviously way out are any other things I should be aware of? IMG_1200.jpg Last edited by johnbuckley; 07-05-2016 at 11:35 AM.

07-05-2016, 11:41 AM	#2
Chuck Sea/Tac Senior Member Join Date: May 2010 Location: Between Seattle & Tacoma Posts: 2,411	Re: B carb fuel starvation Your starving fuel because of a plugged main jet. Get them all to specs first. Check your throttle shaft for wear.

07-05-2016, 11:58 AM	#3
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,251	Re: B carb fuel starvation Also check the ignition, many carb are actually ignition problems.

07-05-2016, 12:00 PM	#4
tbirdtbird BANNED Join Date: May 2012 Location: inside your RAM Posts: 3,134	Re: B carb fuel starvation has he opened the GAV more.....it is there to play with....many fuel starvation issues are because the GAV is turned in too far....don't be afraid of it __________________ '31 180A

07-05-2016, 12:09 PM	#5
johnbuckley Senior Member Join Date: Jul 2010 Location: United Kingdom Posts: 1,557	Re: B carb fuel starvation Chuck Sea, the throttle shaft certainly has some play. I find the A carb is fairly forgiving with throttle shaft wear... But is it more critical on the B carb? Would this play cause lack of suction up the power jet, with the controlled port leaking?

07-05-2016, 12:51 PM	#6
Brian T Senior Member Join Date: May 2010 Location: San Diego,Ca Posts: 1,377	Re: B carb fuel starvation Sponsored Links (Register now to hide all advertisements) I would get the main and power jet back to Biggars specs, and make sure the tube leading to the throttle shaft is clear, the B carb doesn't need the GAV after warmup which eliminates that, I don't believe the throttle shaft is a problem, should you need one they are now available __________________ Nothing can be made foolproof, ---- fools are ingenious bastards. Last edited by Brian T; 07-05-2016 at 12:55 PM. Reason: Added Text

07-05-2016, 01:21 PM	#7
Ron in Quincy Senior Member Join Date: May 2010 Location: Quincy, CA. Posts: 1,708	Re: B carb fuel starvation Make sure the small hole in the throat or passage way , where the fuel from the pickup tube exits when the throttle is opened, is not plugged. Ron

07-05-2016, 02:18 PM	#8
Jacksonlll Senior Member Join Date: Jul 2012 Location: Michigan-- Member of Oakleaf of MARC Posts: 1,686	Re: B carb fuel starvation I don't know anything about a B carb, but if the fuel line goes in too far, like it can on an A carb, and hits the screen in the carb, this is exactly what happens. A little circumcision of the tube will fix it.

07-05-2016, 06:51 PM	#9
Ron in Quincy Senior Member Join Date: May 2010 Location: Quincy, CA. Posts: 1,708	Re: B carb fuel starvation The 32 B and 33-34 C passage ways and throat is no way like the Zenith- or Holley Carburetors that came on the A. Ron

07-05-2016, 07:00 PM	#10
George Miller Senior Member Join Date: May 2010 Location: NC Posts: 2,975	Re: B carb fuel starvation check to see what color the spark is and how far it jumps.