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-   -   cold start requires pumping gas pedal? (https://www.thirdgen.org/forums/carburetors/611957-cold-start-requires-pumping.html)

Handmedown86 04-23-2011 12:47 PM

cold start requires pumping gas pedal?
 
Hey guys,
I just joined this board today to hopefully get some answers. Father-n-law sold me an 86 Z28 w/305 carb for $500. for a cold start, i have to pat the gas pedal about 30+ times to get it running. After that it starts right up fine. Seems its loosing vacuum? Thanks ahead of time for the help.

EvilCartman 04-23-2011 03:10 PM

Re: cold start requires pumping gas pedal?
 
Should only take one or two pumps at most. If you haven't tried starting it today, go out there, take the air filter housing off, pull back the choke blade so you can have a look down the small primary boosters of the carb. Work the throttle and see if any gas is shooting out, if there was, go ahead and try to start it without pumping the gas any more. If nothing is coming out then the gas is draining back out of the carb or the gas is just evaporating out of the fuel bowl.

DoubleV 04-23-2011 11:27 PM

Re: cold start requires pumping gas pedal?
 
Is the choke setting? In other words, does the flapper above the primaries snap shut when you fist pump the gas? If it doesn't, that's most likely your problem along with the possibility of what EvilCartman says about the gas leaking out of the carb overnight ( leaky well plugs ).

built91Z28 04-23-2011 11:54 PM

Re: cold start requires pumping gas pedal?
 
With the warmer weather here now, I doubt its anything to do with a choke. I have a Mighty Demon carb, theres not even a place to mount a choke, and even with my motor built like it is, 1 pump of the gas pedal and it fires right up. Does the same even if it gets into the 30's. The choke will let it run when cold without having to hold the gas down, but shouldnt stop it from firing up.

EvilCartman 04-24-2011 05:13 PM

Re: cold start requires pumping gas pedal?
 
I've found that q-jets need a choke even when warmer weather is around, or at least the one on my other car does. Like yours, my race Demon will start up in cold weather without much trouble.


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