The Ford Barn

RandyMettler · 01-21-2019, 08:19 PM

I have dual 94s on a 8BA. When pulling the air cleaners off the carbs with the engine running, one has a strong sucking sound while one has a barely audible sucking sound. When covering either of the carbs with my hand, one at a time, it kills the motor. I would think the carbs would have equal sucking sounds. To me, this is an indication of a problem with one of the 94s.

I did a propane test to both 94 with no increase in rpms.

Also, when cold and throttling the gas I get misfires. When the engine warms up after 2 minutes I get smooth throttle response. To me, this in an indication of a vacuum leak sealing itself with thermal expansion. Is it possible that a weak coil takes time to warm up to provide consistent strong spark? (I know far fetched)

Any thoughts?

Sorry about multiple post, I am just trying to work through my current problem

Tinker · 01-21-2019, 08:24 PM

Try a Uni Sync to get the vacuum correct.

Do both have chokes on both carbs?

Cold and throttling could just be fuel not firing in the cyclinder. Let it warm up before throttling.

RandyMettler · 01-21-2019, 08:30 PM

Tinker,

Thanks for all your help.

The primary only is set up with a choke. The secondary toward the front of the motor, is the 94 with the strong sucking sound, no choke. It is much stronger than the primary carb, mounted closest to the firewall.

Do you have a favorite uni sync manufacture?

Tinker · 01-21-2019, 08:42 PM

Progressive linkage?

Charlie ny · 01-21-2019, 08:52 PM

Randy,

Look into the air horn and see if both carbs have identical nozzle bars. If OK
there back off the idle SPEED screws so both the carbs are 100% shut, with as sensitive a touch as you can conjure just barely crack the throttle open on each carb. From the just barely cracked setting advance the idle SPEED screws in 1/4 turn at a time until the motor idles where you want it. At this point if your problem is still with
you a UniSyn will help with adjusting the mixture screws. The alternative is to run each carb individually maybe on the buddies single carb motor and set the idle MIXTURE screws that way.
Charlie

RandyMettler · 01-21-2019, 09:17 PM

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Tinker, No I don't have progressive linkage and understand with dual setup you should not. I am running Charlie Price dual 3.5 power valves and 47 jets.

My 94s are not identical. The primary chocked 94 has what I am going to term as a float bowl vent tube located in the center of the air horn. The secondary 94 has a float bowl vent hole, factory drilled in the side of the air horn. I think both accomplish the same function but could be wrong. If you would like pictures I can post tomorrow.

Not sure what "nozzle bars" are, both carbs are identical with the above acceptation.

And thanks Charlie, I sent a check to you today for one of your fuel pumps. Mine is not rebuildable. I am getting fuel in my oil and am tired of changing my oil through this diagnostic proocess.

Tinker · 01-21-2019, 09:21 PM

Have you tried what charlieNY suggested?

Run the idle screws in and set. What the uni-sync is for.

pv and jets seem right on the ballpark mark.

Duels take some time to setup.... and multi carbs always need to be revisited.

.

Talkwrench · 01-21-2019, 09:27 PM

disconnect the carbs from each other when tuning , re connect after you've finished. And check.

Tinker · 01-21-2019, 09:29 PM

Also block off the carb port.

RandyMettler · 01-21-2019, 09:33 PM

Talkwrench

"disconnect the carbs from each other when tuning , re connect after you've finished. And check."

Do you mean remove the fuel supply from one carb at a time when adjusting?

RandyMettler · 01-21-2019, 09:34 PM

Tinker,

When you say "block off the carb port" do you mean the fuel supply to each card individually?

I will try Charlies advice tomorrow. I worked on the car all day, so need to recharge the brain and bones. Oh, and by the way, the alumaseal has seemed to work. I'll see tomorrow.

Tinker · 01-21-2019, 09:36 PM

If your pump isn't overrunning the needle... no. You are looking to find vacuum settings.

RandyMettler · 01-21-2019, 09:47 PM

Tinker,

I don't mean to be dense, but what is "carb port"

Regards

Tinker · 01-21-2019, 09:51 PM

It's a conversation, anyone can pipe in. We all solve problems together.

Carburetor "intake" port.

.

Talkwrench · 01-22-2019, 12:34 AM

No just the throttle linkage, so you do one at a time.

BUBBAS IGNITION · 01-22-2019, 07:11 AM

have found this tool to perform much better than the uni-sync (especially the new ones)..........
https://www.amazon.com/Latest-Rage-D...20224882&psc=1

Ol' Ron · 01-22-2019, 08:49 AM

I'm curious, what distributor are you using. The stock one won't work right. Just another problem.
Gramps

tubman · 01-22-2019, 09:49 AM

Isn't it common knowledge that you should leave the choke mechanism in the secondary carb, even if it is not hooked up or used? When the mechanism is removed, it screws up the airflow in the carb.

flatjack9 · 01-22-2019, 10:52 AM

Tubman is right. You want the choke plate in there. Also I think 47 jets are too small. I would think 49 - 51 unless you are at a high altitude.

RandyMettler · 01-22-2019, 12:50 PM

Bubba,
Thanks for the link headup to the airflow meter.

Regards

01-21-2019, 08:19 PM	#1
RandyMettler Senior Member Join Date: Dec 2018 Posts: 128	Dual 94s one really sucks, one not so much I have dual 94s on a 8BA. When pulling the air cleaners off the carbs with the engine running, one has a strong sucking sound while one has a barely audible sucking sound. When covering either of the carbs with my hand, one at a time, it kills the motor. I would think the carbs would have equal sucking sounds. To me, this is an indication of a problem with one of the 94s. I did a propane test to both 94 with no increase in rpms. Also, when cold and throttling the gas I get misfires. When the engine warms up after 2 minutes I get smooth throttle response. To me, this in an indication of a vacuum leak sealing itself with thermal expansion. Is it possible that a weak coil takes time to warm up to provide consistent strong spark? (I know far fetched) Any thoughts? Sorry about multiple post, I am just trying to work through my current problem Last edited by RandyMettler; 01-21-2019 at 08:24 PM.

01-21-2019, 08:24 PM	#2
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Dual 94s one really sucks, one not so much Try a Uni Sync to get the vacuum correct. Do both have chokes on both carbs? Cold and throttling could just be fuel not firing in the cyclinder. Let it warm up before throttling.

01-21-2019, 08:30 PM	#3
RandyMettler Senior Member Join Date: Dec 2018 Posts: 128	Re: Dual 94s one really sucks, one not so much Tinker, Thanks for all your help. The primary only is set up with a choke. The secondary toward the front of the motor, is the 94 with the strong sucking sound, no choke. It is much stronger than the primary carb, mounted closest to the firewall. Do you have a favorite uni sync manufacture? Last edited by RandyMettler; 01-21-2019 at 08:37 PM.

01-21-2019, 08:42 PM	#4
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Dual 94s one really sucks, one not so much Progressive linkage?

01-21-2019, 08:52 PM	#5
Charlie ny BANNED Join Date: May 2010 Posts: 3,019	Re: Dual 94s one really sucks, one not so much Randy, Look into the air horn and see if both carbs have identical nozzle bars. If OK there back off the idle SPEED screws so both the carbs are 100% shut, with as sensitive a touch as you can conjure just barely crack the throttle open on each carb. From the just barely cracked setting advance the idle SPEED screws in 1/4 turn at a time until the motor idles where you want it. At this point if your problem is still with you a UniSyn will help with adjusting the mixture screws. The alternative is to run each carb individually maybe on the buddies single carb motor and set the idle MIXTURE screws that way. Charlie

01-21-2019, 09:17 PM	#6
RandyMettler Senior Member Join Date: Dec 2018 Posts: 128	Re: Dual 94s one really sucks, one not so much Sponsored Links (Register now to hide all advertisements) Tinker, No I don't have progressive linkage and understand with dual setup you should not. I am running Charlie Price dual 3.5 power valves and 47 jets. My 94s are not identical. The primary chocked 94 has what I am going to term as a float bowl vent tube located in the center of the air horn. The secondary 94 has a float bowl vent hole, factory drilled in the side of the air horn. I think both accomplish the same function but could be wrong. If you would like pictures I can post tomorrow. Not sure what "nozzle bars" are, both carbs are identical with the above acceptation. And thanks Charlie, I sent a check to you today for one of your fuel pumps. Mine is not rebuildable. I am getting fuel in my oil and am tired of changing my oil through this diagnostic proocess. Last edited by RandyMettler; 01-21-2019 at 09:49 PM.

01-21-2019, 09:21 PM	#7
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Dual 94s one really sucks, one not so much Have you tried what charlieNY suggested? Run the idle screws in and set. What the uni-sync is for. pv and jets seem right on the ballpark mark. Duels take some time to setup.... and multi carbs always need to be revisited. .

01-21-2019, 09:27 PM	#8
Talkwrench Senior Member Join Date: Aug 2012 Location: Perth, Western Australia Posts: 2,687	Re: Dual 94s one really sucks, one not so much disconnect the carbs from each other when tuning , re connect after you've finished. And check. __________________ *"Came too close to dying to stop living now!"*

01-21-2019, 09:29 PM	#9
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Dual 94s one really sucks, one not so much Also block off the carb port.

01-21-2019, 09:33 PM	#10
RandyMettler Senior Member Join Date: Dec 2018 Posts: 128	Re: Dual 94s one really sucks, one not so much Talkwrench "disconnect the carbs from each other when tuning , re connect after you've finished. And check." Do you mean remove the fuel supply from one carb at a time when adjusting?

01-21-2019, 09:34 PM	#11
RandyMettler Senior Member Join Date: Dec 2018 Posts: 128	Re: Dual 94s one really sucks, one not so much Tinker, When you say "block off the carb port" do you mean the fuel supply to each card individually? I will try Charlies advice tomorrow. I worked on the car all day, so need to recharge the brain and bones. Oh, and by the way, the alumaseal has seemed to work. I'll see tomorrow. Last edited by RandyMettler; 01-21-2019 at 09:41 PM.

01-21-2019, 09:36 PM	#12
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Dual 94s one really sucks, one not so much If your pump isn't overrunning the needle... no. You are looking to find vacuum settings.

01-21-2019, 09:47 PM	#13
RandyMettler Senior Member Join Date: Dec 2018 Posts: 128	Re: Dual 94s one really sucks, one not so much Tinker, I don't mean to be dense, but what is "carb port" Regards

01-21-2019, 09:51 PM	#14
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: Dual 94s one really sucks, one not so much It's a conversation, anyone can pipe in. We all solve problems together. Carburetor "intake" port. . Last edited by Tinker; 01-21-2019 at 09:57 PM.

01-22-2019, 12:34 AM	#15
Talkwrench Senior Member Join Date: Aug 2012 Location: Perth, Western Australia Posts: 2,687	Re: Dual 94s one really sucks, one not so much No just the throttle linkage, so you do one at a time. __________________ *"Came too close to dying to stop living now!"*

01-22-2019, 07:11 AM	#16
BUBBAS IGNITION Senior Member Join Date: May 2010 Location: SPEEDWAY INDIANA Posts: 4,148	Re: Dual 94s one really sucks, one not so much have found this tool to perform much better than the uni-sync (especially the new ones).......... https://www.amazon.com/Latest-Rage-D...20224882&psc=1 __________________ If it Makes Spark, we do it !!!! www.bubbasignition.com [email protected]

01-22-2019, 08:49 AM	#17
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: Dual 94s one really sucks, one not so much I'm curious, what distributor are you using. The stock one won't work right. Just another problem. Gramps

01-22-2019, 09:49 AM	#18
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,316	Re: Dual 94s one really sucks, one not so much Isn't it common knowledge that you should leave the choke mechanism in the secondary carb, even if it is not hooked up or used? When the mechanism is removed, it screws up the airflow in the carb.

01-22-2019, 10:52 AM	#19
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,526	Re: Dual 94s one really sucks, one not so much Tubman is right. You want the choke plate in there. Also I think 47 jets are too small. I would think 49 - 51 unless you are at a high altitude.

01-22-2019, 12:50 PM	#20
RandyMettler Senior Member Join Date: Dec 2018 Posts: 128	Re: Dual 94s one really sucks, one not so much Bubba, Thanks for the link headup to the airflow meter. Regards Last edited by RandyMettler; 01-22-2019 at 01:42 PM.