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Old 07-18-2010, 02:45 PM   #1
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Default Flame Out after refueling

Can someone explain the principles of why an engine can flame-out after a refueling stop? I've heard it's to do with cold fuel reaching the carb.
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Old 07-18-2010, 03:04 PM   #2
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try this, make you pit guy shake you buggy a few time and it probably wont stall. i know it sounds stupid but it works! ive seen a few of the top pros like ryan cavalarie (check spelling) do it some time. its either that or you need to replace fuel tank or pressure line to the pipe.
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Old 07-18-2010, 03:04 PM   #3
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Sometimes when I pit for someone too cheap to get a proper fuel gun or someone too lame to cut proper refueling holes in thier body I end up spilling fuel on their pipe. That allways seems to cause a flame out on the way out of the pits.


Usually I need to richen my low end a tad or come in 1 lap sooner when this happens to me. Maybe shorten my pressure line an inch.

Some drivers get on the gas too hard after a bad pit and flame out. Then you got the guys that crash 78 times on the way down pit lane. I can go on....
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Old 07-18-2010, 03:37 PM   #4
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I posted a thread much like this last year when we first started. The advice we've found to help the most is to rev the engine once before the tank is opened then let it idle only while the tank is open. Then a few revs before leaving the pits. It was said that when the lid is open there is no fuel pressure so if you rev while it's open the engine uses what little it can out of the line and you end up with a large air bubble from no fuel pressure. Then usually the first turn or lift point after the pit thedreaded flameout occurs. We've followed thisrule with much less trouble since. My son and many others shake the car too before putting it down. I don't know what this is supposed to do but many of the cool guys do it so we do too! LOL!

Good luck!
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Old 07-18-2010, 04:18 PM   #5
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Originally Posted by Babygrand48 View Post
I posted a thread much like this last year when we first started. The advice we've found to help the most is to rev the engine once before the tank is opened then let it idle only while the tank is open. Then a few revs before leaving the pits. It was said that when the lid is open there is no fuel pressure so if you rev while it's open the engine uses what little it can out of the line and you end up with a large air bubble from no fuel pressure. Then usually the first turn or lift point after the pit thedreaded flameout occurs. We've followed thisrule with much less trouble since. My son and many others shake the car too before putting it down. I don't know what this is supposed to do but many of the cool guys do it so we do too! LOL!

Good luck!
That's exactly what happened to me today. I came in, got fuel, and then the buggy died right after I went through the first turn. It was a turn where you jump up on top and then drive down the other side. When I came through it the engine leaned out and died right after. Oddly enough though my pit guy went and got the buggy, restarted it and got me back on the track without losing my second place position.
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Old 07-18-2010, 04:21 PM   #6
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I used to have my driver rev when I picked the car up.
Then i'd refuel.
Then I hold the car out so he could rev, then I'd drop it.

Too hard to coordinate under pressure. Now I just grab it, fuel it, drop it.

What in the world could shaking the car do??? Is it after filling???
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Old 07-18-2010, 04:44 PM   #7
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Originally Posted by Zerodefect View Post
I used to have my driver rev when I picked the car up.
Then i'd refuel.
Then I hold the car out so he could rev, then I'd drop it.

Too hard to coordinate under pressure. Now I just grab it, fuel it, drop it.

What in the world could shaking the car do??? Is it after filling???
idk what it does but all i know once we started doing it, no flame outs and its not rich coming off the pits. shake it fast and hard for a quick second right before you drop it, works everytime! i rev it a little when they shake mine but others dont rev, either way it works.
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Old 07-18-2010, 04:49 PM   #8
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i dont know if you do this but if you tap the gas - even a little - while the fuel tank is open and the tank is low you will suck alot of air into the fuel line and flame out just as you hit the straight away
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Old 07-18-2010, 05:33 PM   #9
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Never a day that I don't learn something on this site. I never knew not to rev while the lid was open
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Old 07-18-2010, 05:54 PM   #10
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It's usually the tune on the motor, too rich on the bottom .
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Old 07-18-2010, 09:17 PM   #11
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Originally Posted by bevofrancis View Post
That's exactly what happened to me today. I came in, got fuel, and then the buggy died right after I went through the first turn. It was a turn where you jump up on top and then drive down the other side. When I came through it the engine leaned out and died right after. Oddly enough though my pit guy went and got the buggy, restarted it and got me back on the track without losing my second place position.
Funny how that works, we had exactly that issue, idk if it's related to the first drop to low speed after fuel stop or what but it happened to us religiously. We actually went and spent an hour or so practicing stops, tried tuning changes etc and the no rev with the tank open strategy was all that worked. It even makes logical sense!

as for the fuel gun, we have a Pro Line model and on top of the fact that it leaks we used it for one stop and flamed in the pits! Needless to say no more trying that again til we can practice some with it!
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Old 07-18-2010, 09:29 PM   #12
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Very common when pit stops are being stretched to the very limit. If the tank is dry enough and you wing on it, it will suck a nice big bubble of air into the fuel line. It basically runs the engine out of fuel even though the tank is full, because the line is dry. Solution is to either not push it as far or don't rev it while fueling. Without back pressure due to the lid being open for fueling, it gets much easier for the engine to suck in a big air bubble. There is nothing forcing the fuel into the engine. Usually when the tank is still pretty full(like 1/4 inch of fuel +) during a pit, it is much less common for a flame out due to this. There are plenty of other things like a bad tune or a dying plug, etc... that can cause a flame out after fueling. But the air bubble is pretty common as well.
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Old 07-18-2010, 09:36 PM   #13
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Originally Posted by JAMMINKRAZY View Post
Very common when pit stops are being stretched to the very limit. If the tank is dry enough and you wing on it, it will suck a nice big bubble of air into the fuel line. It basically runs the engine out of fuel even though the tank is full, because the line is dry. Solution is to either not push it as far or don't rev it while fueling. Without back pressure due to the lid being open for fueling, it gets much easier for the engine to suck in a big air bubble. There is nothing forcing the fuel into the engine. Usually when the tank is still pretty full(like 1/4 inch of fuel +) during a pit, it is much less common for a flame out due to this. There are plenty of other things like a bad tune or a dying plug, etc... that can cause a flame out after fueling. But the air bubble is pretty common as well.
very true!!!!! also alot of guys seem to want to give throttle when on lid waiting for marshall to flip back over, same thing happens here, stay off throttle and will stay running (if clunk is working right) as soon as you give a crap ton of throttle it is bound to suck air, less throttle the better
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Old 07-18-2010, 09:39 PM   #14
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Quote:
Originally Posted by Babygrand48 View Post
I posted a thread much like this last year when we first started. The advice we've found to help the most is to rev the engine once before the tank is opened then let it idle only while the tank is open. Then a few revs before leaving the pits. It was said that when the lid is open there is no fuel pressure so if you rev while it's open the engine uses what little it can out of the line and you end up with a large air bubble from no fuel pressure. Then usually the first turn or lift point after the pit thedreaded flameout occurs. We've followed thisrule with much less trouble since. My son and many others shake the car too before putting it down. I don't know what this is supposed to do but many of the cool guys do it so we do too! LOL!

Good luck!
bingo

that and an improperly tuned engine = flameouts
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Old 07-18-2010, 09:40 PM   #15
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bingo

that and an improperly tuned engine = flameouts


what about a dirty clogged filter i know that will cause a flameout .
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