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Old 09-02-2010, 10:13 AM   #16
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On JPX .21 it is usually either a too rich LSN or a bad or unsuitable plug..... basically during your pitstop your engine is loading up and then stalling out when you get back on throttle....You need to run a leaner LSN setting or fine tune your fuel/plug combination a little better...
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Old 09-02-2010, 10:17 AM   #17
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When you refuel your tank builds excess compression, then when you close the lid it compresses even more air into the tank which makes you run rich and can flood the engine. You could lean it out alittle more on the bottom end and/or blip the throttle a few times when refueling and just before taking off. Also when taking off be sure not to gun it, just blip it a few times to clear the excess fuel left in the crankcase and then you should be good to go.
Actually, when you open the fuel tank lid, the tank loses compression. Unless there is a vacuum in the tank, which I don't think is the case.
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Old 09-02-2010, 10:22 AM   #18
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When you refuel your tank builds excess compression, then when you close the lid it compresses even more air into the tank which makes you run rich and can flood the engine. You could lean it out alittle more on the bottom end and/or blip the throttle a few times when refueling and just before taking off. Also when taking off be sure not to gun it, just blip it a few times to clear the excess fuel left in the crankcase and then you should be good to go.
I blip the throttle right after refueling (with closed tank) and before taking off so i think it's not being flooded. Is it possible to stop the engine by dropping a few drops of fuel on the pipe? If so, that could be the reason, but again - it haven't happened to me before... and i don't belive that my father haven't dropped a single drop of fuel on the pipe before.

EDIT: I run O.S. P4 plug and Byron Race 25% fuel
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Old 09-02-2010, 11:27 AM   #19
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I think if you rev the engine with the lid open it causes you to suck up a big air bubble and when that gets to the engine it dies for lack of fuel.... maybe I'm wrong...
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Old 09-02-2010, 11:45 AM   #20
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I still think that its because your running rich somewhere. When ever I hear pro guys talk about it, they alway mention change in tune or something to that degree.
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Old 09-02-2010, 11:48 AM   #21
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I wanted to ask you what could be the reason of flameout after refueling. It happened to me three times in last main.
Every time i went out of pit the engine stopped working (and it was always after 4-6sec).
I'm using Losi gun but it happened also when refueling with fuel bottle.
It shouldn't be glow plugs fault and i don't have leaking fuel tubing or tank.

It looks like the engine has to much fuel at low rpms but it doesn't - it was running good and the temperature was ok.

I run JPX .21 that has 3 gallons on it (compression almost like in a new engine).

Do you have any ideas? It haven't happened to me before.

I hope you can understand something i wrote. English is not my language.



i would, have to say your bottom end needle is tuned to rich is there a lot of smoke when you hit the throttle ?


donat: if your bottom end is tuned right you dont have to blip the throttle when your getting refueled .
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Old 09-02-2010, 12:15 PM   #22
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Originally Posted by Donat View Post
I wanted to ask you what could be the reason of flameout after refueling. It happened to me three times in last main.
Every time i went out of pit the engine stopped working (and it was always after 4-6sec).
I'm using Losi gun but it happened also when refueling with fuel bottle.
It shouldn't be glow plugs fault and i don't have leaking fuel tubing or tank.

It looks like the engine has to much fuel at low rpms but it doesn't - it was running good and the temperature was ok.

I run JPX .21 that has 3 gallons on it (compression almost like in a new engine).

Do you have any ideas? It haven't happened to me before.

I hope you can understand something i wrote. English is not my language.
Possible tune issue. LSN could be set too rich.

Other possibilities..

If you blip the throttle while someone's filling you, IE with the lid open, you can suck air into the fuel line which will cause the engine to essentially run out of fuel even though the tank is full.

You need to clear the engine out after fueling. Excess pressure from the lid closing and just the fueling process in general will push more fuel into the engine than normal. This causes the engine to run rich for a few seconds which can cause it to load up and die, especially if it is tuned a bit rich to begin with.

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i would, have to say your bottom end needle is tuned to rich is there a lot of smoke when you hit the throttle ?


donat: if your bottom end is tuned right you dont have to blip the throttle when your getting refueled .
More bad advice. You absolutely should clear your engine out after fueling for the reasons above.
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Old 09-02-2010, 12:21 PM   #23
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Originally Posted by JAMMINKRAZY View Post
Possible tune issue. LSN could be set too rich.

Other possibilities..

If you blip the throttle while someone's filling you, IE with the lid open, you can suck air into the fuel line which will cause the engine to essentially run out of fuel even though the tank is full.

You need to clear the engine out after fueling. Excess pressure from the lid closing and just the fueling process in general will push more fuel into the engine than normal. This causes the engine to run rich for a few seconds which can cause it to load up and die, especially if it is tuned a bit rich to begin with.



More bad advice. You absolutely should clear your engine out after fueling for the reasons above.



i guess, i wrong than but if your not running rich on the low end and your refueling why do you have to blip the throttle i dont and it doesnt die.
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Old 09-02-2010, 12:22 PM   #24
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Quote:
Originally Posted by JAMMINKRAZY View Post
Possible tune issue. LSN could be set too rich.

Other possibilities..

If you blip the throttle while someone's filling you, IE with the lid open, you can suck air into the fuel line which will cause the engine to essentially run out of fuel even though the tank is full.

You need to clear the engine out after fueling. Excess pressure from the lid closing and just the fueling process in general will push more fuel into the engine than normal. This causes the engine to run rich for a few seconds which can cause it to load up and die, especially if it is tuned a bit rich to begin with.



More bad advice. You absolutely should clear your engine out after fueling for the reasons above.



i guess, i wrong than but if your not running rich on the low end and your refueling why do you have to blip the throttle i dont and it doesnt die.

now if the glow plug isnt good thats a diffrent story.
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Old 09-02-2010, 12:31 PM   #25
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The engine should be slightly rich right after fueling, from pushing the extra fuel into the engine and the idling that is done while fueling. If not then you might be running it too lean or your idle is set too high. The engine should build up fuel in the crankcase after idling for 20-30 seconds, thats the sign of a good tune and refueling just compounds the issue by adding even more fuel to the mix. Just a blip or 2 will clean the extra fuel out and then you are free to drive it like you stole it
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Old 09-02-2010, 12:35 PM   #26
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The engine should be slightly rich right after fueling, from pushing the extra fuel into the engine and the idling that is done while fueling. If not then you might be running it too lean or your idle is set too high. The engine should build up fuel in the crankcase after idling for 20-30 seconds, thats the sign of a good tune and refueling just compounds the issue by adding even more fuel to the mix. Just a blip or 2 will clean the extra fuel out and then you are free to drive it like you stole it


well trust me i still have smoke coming out of pipes i never tune my too lean
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Old 09-02-2010, 12:36 PM   #27
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Thats also why they say to tune at a half tank, not when its full or empty. Full tank = richer, empty tank = leaner.
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Old 09-02-2010, 12:38 PM   #28
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Thats also why they say to tune at a half tank, not when its full or empty. Full tank = richer, empty tank = leaner.


im going to start tuning it at a half tank now.
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Old 09-02-2010, 12:40 PM   #29
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well trust me i still have smoke coming out of pipes i never tune my too lean
You can still have smoke and be too lean. The smoke coming out might be because its extra rich after refueling. After i refuel i get lots of smoke, not just a normal amount. And then after a couple blips it cuts back down to where it should be in terms of smoke. The smoke also changes based on the oil % you are running in the fuel. But some smoke is better than no smoke, thats for sure
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Old 09-02-2010, 12:42 PM   #30
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im going to start tuning it at a half tank now.
I hope you aren't being sarcastic, i didn't mean the comment to come off as rude. Thats just what i've always read and heard. And have picked it up as a standard practice along the way.
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