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1941 P-12 Plymouth 6-flat Motor running bad at high RPM


JohnnyMaryjo
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why is it when I step on the gas full throttle the motor chokes out

like it is asking for gas or drowning in it 

but at normal  rpm like around 2500 - 3000  the motor runs fine 

we have done almost everything  from new carb. all new wiring, reconditioned motor ,voltage  , distributor, and on and on?

what else is there  ?

  

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"New" everything is bothersome.

 

Have you tested ignition to see if the dwell and timing are correct at idle? Is the advance mechanism on the distributor functioning? Have you tested the carburetor accelerator pump?

 

"New", especially today, generally means shiny, not necessarily good.

 

With no testing reported, first GUESSES are either advance mechanism isn't, or the accelerator pump isn't.

 

Jon

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Hello

when I give the car some gas it goes great but when I ask it for all of it it will sputter , spit, chock and I have to let off the gas and drive it where it will accept the normal 

why is this .it was running great until this mech. was going to mess with the carb. cause it was running to rich and black smoke out the pipe.

from he touching it  .It never ran right again.I asked him what he did he said he just placed different jets in the carb. I told him to place it back the way it was I can handle black smoke . but he moved on and passed never did finish this What Mech can take this 1 bar. carter carb and make it correct.

Who do we trust

thanks

Johnny

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" I will have to ask my mech. if this is everything he has done?"

This statement raises my eyebrows. Good troubleshooting means understanding what it's supposed to do and why. 

I hope he gets it sorted out.

 

-Test distributor vacuum advance

-Check ignition timing

-Set dwell

-Plugs clean?

-Check carb for air leaks. Float setting.

-Remove air filter, engine turned off. Look down into carb air horn. Cycle throttle by hand. Is a raw stream fuel being shot-in when throttle is opened quickly? It should be.

-With engine running, air filter off. Rev up engine quickly. Have a mustard squirter bottle of fuel ready. When engine stalls out, squirt a little raw fuel in carb yourself by hand. Better? Worse?

-Engine running. Cycle the choke closed a bit to cut off air supply slightly.  Not all the way to cause the engine to stall. Quickly rev up engine. Better? Worse?

 

That'll help you get closer to the problem.

 

Edited by keithb7 (see edit history)
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14 hours ago, keithb7 said:

" I will have to ask my mech. if this is everything he has done?"

This statement raises my eyebrows. Good troubleshooting means understanding what it's supposed to do and why. 

I hope he gets it sorted out.

 

-Test distributor vacuum advance

-Check ignition timing

-Set dwell

-Plugs clean?

-Check carb for air leaks. Float setting.

-Remove air filter, engine turned off. Look down into carb air horn. Cycle throttle by hand. Is a raw stream fuel being shot-in when throttle is opened quickly? It should be.

-With engine running, air filter off. Rev up engine quickly. Have a mustard squirter bottle of fuel ready. When engine stalls out, squirt a little raw fuel in carb yourself by hand. Better? Worse?

-Engine running. Cycle the choke closed a bit to cut off air supply slightly.  Not all the way to cause the engine to stall. Quickly rev up engine. Better? Worse?

 

That'll help you get closer to the problem.

 

thank you tried all of it no change in the way it is acting  ran the same with all you tld me to do

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Just now, JohnnyMaryjo said:

thank you tried all of it no change in the way it is acting  ran the same with all you tld me to do

 

15 hours ago, EmTee said:

Has the fuel pump been tested for pressure AND volume?

replaced 3 of them good better best

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On 8/3/2022 at 8:10 AM, Ben Bruce aka First Born said:

" Asking for gas"!    I like that.

  And my bet is that it is doing so.  What happens if the throttle is opened slowly to wide open?

 

  Ben

same no difference

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On 8/3/2022 at 8:10 AM, Ben Bruce aka First Born said:

" Asking for gas"!    I like that.

  And my bet is that it is doing so.  What happens if the throttle is opened slowly to wide open?

 

  Ben

chokes out wants to stop the moter from going until I let up on the gas peddle then it will continue to run 

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21 hours ago, plymouthcranbrook said:

Not knowing where you are limits us in suggesting someone. That said Then and Now Automotive in Weymouth, Ma. Rebuilt a B&B single barrel for me several years ago and it worked well for a long time.

do you have a ph # or e mail for them or web site

thanks

Johnny

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I want to say it's the carb. these have a metering rod as I remember and if they changed the jet, could have adjusted the rod incorrectly or whatever. Even broke the tip off the rod, You need some one that understands carbs to take a look at it.

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