carb flooding
Thread Starter
Melting Slicks
Joined: Feb 2000
Posts: 3,052
Likes: 0
From: Vancouver BC, Canada
carb flooding
after sitting for more than about an hour (still very warm), i am having major difficulties starting my car. i 've determined that the carb is flooding the intake. i verified, and could see gas pooled.
whats going on? float is not likely sticking, and i tried lowering it to .375 from .250. last year i epoxied the well plugs. right now i have the carb off, and filled the bowl with carb cleaner, waiting to see if it leaks. however, it would have to be a pretty substantial leak by looking at the amount of gas in the intake, in such a short time.
let's start at the beginning, what are the causes of flooding?
whats going on? float is not likely sticking, and i tried lowering it to .375 from .250. last year i epoxied the well plugs. right now i have the carb off, and filled the bowl with carb cleaner, waiting to see if it leaks. however, it would have to be a pretty substantial leak by looking at the amount of gas in the intake, in such a short time.
let's start at the beginning, what are the causes of flooding?
Drifting
Joined: Nov 2001
Posts: 1,502
Likes: 0
From: Elyria Ohio
Re: carb flooding (Turbo-Jet)
Are you sure your needle and seats are not sticking???? I had a bear of a time with mine. I am using a glass fuel filter and crap still gets past it and gets my secondary needle sticking.
Bob
Bob
Race Director
Joined: Oct 2000
Posts: 15,044
Likes: 79
From: central FL, near the beach.
Re: carb flooding (Turbo-Jet)
the cure for hot soak carb boiling is EFI.
Being stubborn, i converted the heat riser passage to a "well".
this is the 3rd year in FL with no further problems.
Others will chime in with heat shields and carb insulator cures.
To verify that it has this problem, all you have to do is park it, for this test, with the hood open. if it does not puke gas, it is heat soak/boil over :smash:
Being stubborn, i converted the heat riser passage to a "well".
this is the 3rd year in FL with no further problems.
Others will chime in with heat shields and carb insulator cures.
To verify that it has this problem, all you have to do is park it, for this test, with the hood open. if it does not puke gas, it is heat soak/boil over :smash:
Thread Starter
Melting Slicks
Joined: Feb 2000
Posts: 3,052
Likes: 0
From: Vancouver BC, Canada
Re: carb flooding (drives61)
thanks.
so what is happing is that the engine is hot, shut off, and the heat 'boils' the fuel? must be very hot? wouldn't the fuel evaporate as soon as it reaches the manifold?
i never had this problem before, and have not made any jetting/mixture changes. just lowered the float and been playing with timing.
Q: could over-advanced base timing make for hard starting, and gas then collects after 5-10 s of cranking, making it worse?
so what is happing is that the engine is hot, shut off, and the heat 'boils' the fuel? must be very hot? wouldn't the fuel evaporate as soon as it reaches the manifold?
i never had this problem before, and have not made any jetting/mixture changes. just lowered the float and been playing with timing.
Q: could over-advanced base timing make for hard starting, and gas then collects after 5-10 s of cranking, making it worse?
Race Director
Joined: Oct 2000
Posts: 15,044
Likes: 79
From: central FL, near the beach.
Re: carb flooding (Turbo-Jet)
try different gas, some have a higher boiling point. Does it have summer gas? Winter gas boils at a lower temp to help starting, if you got some of that :nopity
Gas will boil around 200 degrees, some much lower. It will boil over into the intake and run into the cyl's. That's why it is hard to start, some flood, while others stay dry. This is why it helps to give it a pump, then hold floored to start
Yes lots will evaporate; not good for MPG :lol: :crazy:
Gas will boil around 200 degrees, some much lower. It will boil over into the intake and run into the cyl's. That's why it is hard to start, some flood, while others stay dry. This is why it helps to give it a pump, then hold floored to start
Yes lots will evaporate; not good for MPG :lol: :crazy:
Melting Slicks
Joined: Oct 2001
Posts: 2,065
Likes: 1,395
From: Halifax, Nova Scotia, Canada
Re: carb flooding (Turbo-Jet)
Qjet floats do go bad. I've had a couple over the years.
Seems like they absorb the fuel when they get old and they tend to sink a bit.
I would replace it anyway, just to be sure.
Seems like they absorb the fuel when they get old and they tend to sink a bit.
I would replace it anyway, just to be sure.
Thread Starter
Melting Slicks
Joined: Feb 2000
Posts: 3,052
Likes: 0
From: Vancouver BC, Canada
Re: carb flooding (Barry's70LT1)
float is new, but i am thinking that the needle must not be closing all the way or quickley enough. i seem to recall that the needle was snug to the float arm, usually it should be hanging loosely, correct? can i rebend that little clip thingy?
pretty sure it is not boiling over, as i just dried away all fuel and reinstalled carb. wouldn't start, until after more thatn 45 s of attempts, and manifold was full of gas pools again. then it started instantly, ran for 45 s, and then died instantly. yet to be able to restart. :confused:
[Modified by Turbo-Jet, 7:42 PM 6/21/2002]
pretty sure it is not boiling over, as i just dried away all fuel and reinstalled carb. wouldn't start, until after more thatn 45 s of attempts, and manifold was full of gas pools again. then it started instantly, ran for 45 s, and then died instantly. yet to be able to restart. :confused:
[Modified by Turbo-Jet, 7:42 PM 6/21/2002]
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Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
Re: carb flooding (Turbo-Jet)
When you shut it off, 3 things control fuel from getting into the manifold. Float level, needle and seat and "well plugs" Life your Q-Jet off after running (cooled down) and fell the well plugs for the primary and secondary. Get one or both are leaking. If so, remove it, lightly tap around the lead sealed plugs and cover with JB Weld and let dry. If you still have trouble, are you running with open exhaust crossover with a go engine? Meaning - 200+ degrees. You may also be boiling the fuel out of the carb.