carb or fuel pump

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Apr 15, 2005 | 01:45 PM

greyghost79

Thread Starter

Burning Brakes

Joined: Nov 2004

Posts: 1,028

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From: San Antonio Texas

carb or fuel pump

79 L82. stock fuel pump. Q-Jet. when in gear (350 auto), holding brake and increasing rpm to say 1200 to 1500 preparing to launch. if I let off the gas (while still at standstill with brake on) the engine will die and is hard to restart. must hold gas pedal to floor (like it flooded). no other problems. accelerates smoothly all the way to redline.

Is this carb problem or fuel pump? i tend to think carb because of not having problems on acceleration. if carb, what is the problem?

thanks for any info.

Apr 15, 2005 | 03:24 PM

crazydalys

Instructor

Joined: Apr 2004

Posts: 196

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From: St Paul MN

Very interesting. Maybe it has something to do with the choke? Just a guess.

Apr 15, 2005 | 04:04 PM

greyghost79

Thread Starter

Burning Brakes

Joined: Nov 2004

Posts: 1,028

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From: San Antonio Texas

vehicle fully warmed up, choke wide open (manual choke).

Apr 15, 2005 | 04:54 PM

R. Bruno

Drifting

Joined: Feb 2001

Posts: 1,603

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From: San Francisco, CA

I am not an expert, but sounds like the float or dirt in the needle and seat. It would cause a flooding condition if the float was sinking or sunk or if the needle wasn't seating properly. i would rebuild the carb and see where that gets you.

Apr 15, 2005 | 04:59 PM

greyghost79

Thread Starter

Burning Brakes

Joined: Nov 2004

Posts: 1,028

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From: San Antonio Texas

sounds reasonable but why would it only "flood" under this one condition.

Apr 15, 2005 | 06:25 PM

R. Bruno

Drifting

Joined: Feb 2001

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From: San Francisco, CA

Quote:

Originally Posted by greyghost79

sounds reasonable but why would it only "flood" under this one condition.

When you are reving it, the float is dropping and allowing more fuel to poor in right? Then when you let off, and the float sticks or the needle sticks (if this is indeed the problem) it floods. If you were driving, and you let off, I think the demands of the motor would be such that it would be less drastic and it might not stall. The floats tend to get saturated if they are neoprene or they can leak if they are brass and overtime they don't float the way they should.