Carb Fire on start up --- Help!
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Racer
Joined: Nov 2001
Posts: 326
Likes: 19
From: Napa CA
Carb Fire on start up --- Help!
I am using a Demon 750 (no choke) on a new Fast Burn 385 and I get a nice little carb fire when starting the engine!!!
Any suggestions? The car runs great after that, but those carb fires really bug me in my little plastic car (69 convertible).
Thanks, Eric. :mad
Any suggestions? The car runs great after that, but those carb fires really bug me in my little plastic car (69 convertible).
Thanks, Eric. :mad
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Joined: Jan 2003
Posts: 65
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From: Sooke B.C.
Re: Carb Fire on start up --- Help! (EricU)
Hi , I had this problem once, and I would highly suggest you get yourself and and the Vette to a carb.specialist. In my case they just did a choke adjustmemt. I guess it depends on what you want unfortunately, or what you can afford; either way my car was fixed and lllllllllllllllllthe cost. :cheers:
Tech Contributor
Joined: Aug 1999
Posts: 14,377
Likes: 6,377
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Carb Fire on start up --- Help! (EricU)
Eric -
When running without a choke, you run into a lean condition when cold-starting. You end up with a lean-out backfire, which starts the carb fire - pretty common. If you want to go choke-less, about the only thing you can do is always start it with an air cleaner in place, and keep pumping the heck out of the gas pedal so the accel pump keeps it rich enough to prevent the lean-out. You might also want to check your mixture once you're warmed up and see if you can justify a size or two increase in jet size - this will help your cold-start lean condition. This all assumes, of course, that your timing is set up correctly...
When running without a choke, you run into a lean condition when cold-starting. You end up with a lean-out backfire, which starts the carb fire - pretty common. If you want to go choke-less, about the only thing you can do is always start it with an air cleaner in place, and keep pumping the heck out of the gas pedal so the accel pump keeps it rich enough to prevent the lean-out. You might also want to check your mixture once you're warmed up and see if you can justify a size or two increase in jet size - this will help your cold-start lean condition. This all assumes, of course, that your timing is set up correctly...
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Re: Carb Fire on start up --- Help! (EricU)
Check the timing at idle. You may need to run less initial advance. Lean + advanced timing = fire. Best thing would be to get a choke.
Another thing to try is pumping the accelerator one more time before cranking, and then as soon as it fires blip the throttle. Extra gas from the acc pump may be enough to keep it from backfiring.
Another thing to try is pumping the accelerator one more time before cranking, and then as soon as it fires blip the throttle. Extra gas from the acc pump may be enough to keep it from backfiring.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Carb Fire on start up --- Help! (EricU)
Most likely a timing issue. Or incorrect firing order. If it pops and catches fire, just crank the engine to suck the flames back in. Thats the best way to put the fire out.
