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Old 06-02-2009, 06:51 AM   #1
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Default I read the tuning bible and my RC cars manual, still no answer.

So I come to you guys. Sorry if I'm sounding needy, but I just need a little bit of direction.

I just completed breaking in my engine, but after about a tank of fuel, it starts running weird. I go full throttle and it stalls. It runs great through the first tank though! That's what drives me nuts. Lol. Has anyone had this problem, and how to I adjust my engine so it doesn't do this? Thanks in advance!
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Old 06-02-2009, 07:07 AM   #2
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I would rule out the obvious first:

Glow plug
Air leak
Bad Fuel tank

Then go back to stock settings and retune....

Hope it helps.
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Old 06-02-2009, 07:10 AM   #3
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Make sure your clutch is good, too. That has caused me a lot of grief in the past. Clutch was coming in too early, allowing the engine to load up over time and die when I gave it full throttle, often 5-7 minutes into a tank.
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Old 06-02-2009, 07:14 AM   #4
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that means your wayyy too lean on the top end. also make your idle a littlebit higher
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Old 06-02-2009, 07:21 AM   #5
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Quote:
Originally Posted by eighty2 View Post
So I come to you guys. Sorry if I'm sounding needy, but I just need a little bit of direction.

I just completed breaking in my engine, but after about a tank of fuel, it starts running weird. I go full throttle and it stalls. It runs great through the first tank though! That's what drives me nuts. Lol. Has anyone had this problem, and how to I adjust my engine so it doesn't do this? Thanks in advance!
How many tanks have you run through your engine so far? How long are you staying on full throttle? I normally don't go full throttle until about seven or eight tanks. And I don't stay on it long. You should be blipping the throttle during breakin.
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Old 06-02-2009, 08:45 AM   #6
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The above are all very good suggestions! As stated rule out the simple stuff first. Stating your setup is helpful when asking for assistance, I.E which engine, fuel brand, glow plug ect. IMO I don't think it's a tuning issue due to the engine running good for a tank. I think that your engine has an air leak when it gets up to temp. I have a STS .28 that takes a tank to completely get up to temp. I fought with it running fine for the 8 minutes or so then it would run lean. The thermal expansion of my engine was creating an air leak around the starter shaft that runs thru the back plate. I'd double check that your engine is sealed up real good!
Second thought, though far fetched could be needle settings. You might have your LSN too rich and your HSN too lean with a high idle to keep it running. It will run good till you do a WOT run which clears out all the excess fuel and you experience a lean condition. Reset to stock settings and adjust HSN first, then LSN followed by idle.
One other thing to try is after you run your truck for the first tank richen up the HSN quite a bit. If it will run sloppy rich then fine, run some tanks like this thru her. Try leaning it out very slowly over time. If when you lean it out it stalls or lets out the lean whine richen it back up. If it refuses to cooperate then you can run it sloppy rich with the glow igniter on. The thought here is to run some tanks so the engine can run in some more. I do this with leaking front bearings which sometimes seal up using this method.
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Old 06-02-2009, 08:49 AM   #7
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Quote:
Originally Posted by Trevato View Post
The above are all very good suggestions! As stated rule out the simple stuff first. Stating your setup is helpful when asking for assistance, I.E which engine, fuel brand, glow plug ect. IMO I don't think it's a tuning issue due to the engine running good for a tank. I think that your engine has an air leak when it gets up to temp. I have a STS .28 that takes a tank to completely get up to temp. I fought with it running fine for the 8 minutes or so then it would run lean. The thermal expansion of my engine was creating an air leak around the starter shaft that runs thru the back plate. I'd double check that your engine is sealed up real good!
Second thought, though far fetched could be needle settings. You might have your LSN too rich and your HSN too lean with a high idle to keep it running. It will run good till you do a WOT run which clears out all the excess fuel and you experience a lean condition. Reset to stock settings and adjust HSN first, then LSN followed by idle.
One other thing to try is after you run your truck for the first tank richen up the HSN quite a bit. If it will run sloppy rich then fine, run some tanks like this thru her. Try leaning it out very slowly over time. If when you lean it out it stalls or lets out the lean whine richen it back up. If it refuses to cooperate then you can run it sloppy rich with the glow igniter on. The thought here is to run some tanks so the engine can run in some more. I do this with leaking front bearings which sometimes seal up using this method.
Lastly make sure your using.
is it a vspec ?
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Old 06-02-2009, 08:59 AM   #8
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I have a Traxxas Nitro Sport, and I guess I am about 6 tanks through. Pro .15 engine. I guess I'm not fully broken in.
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Old 06-02-2009, 09:02 AM   #9
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I have a Traxxas Nitro Sport, and I guess I am about 6 tanks through. Pro .15 engine. I guess I'm not fully broken in.
probably the carb , those carbs have some issues , not all of them but a few
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