Runs until 1/4 throttle then dies

[yammaha]

Hi, My problem is that my motor runs great until about 1/4 throttle then just dies. It even idles great. Its not running really rich or lean, i got a good smoke trail until, dead. Its a losi m26ss, What could cause this i have tryed several different tunes and nothing works. Thanks

 

[w bill]

If your sure your settings are right you may want to check your fuel filter make sure its clear and make sure you fuel tank is sealing up.

 

[yammaha]

Ok thanks ill try that

 

[MotoGod]

If it dies at 1/4 throttle....that is about where your high speed needle takes over with the fuel air mixture. So it's either too rich or too lean.....Lean it 2 hours...see if it stays running and go from there. If it gets worse or stays the same...you're probably too lean on the high speed needle. So add the 2 hours back in...and richen it 2 more on top of that and see where you are at. If you know the factory settings....it might be good to go back to them and re-tune from there.

 

[yammaha]

ok thanks

 

[Rolex]

You meant to say "Engine" didn't you?

 

[mtaylortank]

could a crappy plug play a part in this at all???? was just brainstorming ideas... could be air leak cause until 1/4 throttle it really isnt burning a hole lot of fuel right and then when you try to give it some it aint getting enough fuel to keep it running.... After it dies how hard is it to restart your buggy????

 

[MotoGod]

Not typically from what I have seen Matt. Hotter plugs tend to give you a wider tuning window...colder plugs tend to narrow the window, but will reward you if you get it in the sweet spot with more power and such. Nitro content plays a part in what heat range to run as well.

Usually an air leak will make the engine run hot all over, but it shouldn't stall the engine past 1/4 throttle if it runs good up until 1/4 throttle. Air Leak would affect both needles and not just what seems like one needle. Tuning is all trial and error anyway ;-) Eventually you fail enough that you end up knowing what to do. haha

 

[mtaylortank]

good to know about the air thing now i know what to look for even more... one step at a time, thats why I love this forum because chances are atleast one other person out there has done it atleast once.... good luck with your rig yammaha

 

[yammaha]

Thanks, Ill give her a try!!

 

[knall]

Try a new plug. My buddies truck was doing the same thing. It would run perfectly fine, and even idle mint. but if ya tried to go over 1/4 - 1/2 throttle.... it shut off like a switch.

 

[yammaha]

Thanks, everyone

 

[mtaylortank]

i was thinking the plug too because if it aint hot enough it wouldnt burn all the fuel right??????

 

[Candyman]

Just a general tip...

When you're stuck in a perplexing tuning situation and you're not sure what to do, return the HSN and LSN to factory recommended settings and start tuning again from there. In the process of tuning you can sometimes get your needles so out of whack that it's impossible to tell where you're at. Go back factory settings and slowly proceed from there.

 

[yammaha]

Thanks a million guys, i got her running good today, you guys are awsome

 

[MotoGod]

What was the problem ultimately?

 

[yammaha]

The High speed needle was about 2 turns to lean. the last time i ran it was in the winter.

 

[mtaylortank]

that does make a difference and i just thought of what my problem is probly bout the same on one of my rigs

 

[MotoGod]

Excellent. Glad you got it running man....

 

[yammaha]

Thanks