How do you tune a XXX-NT?

[Wildcatfreek]

I just bought a XXX-NT that had 5 tanks of 20% Monster fuel run through it. Now I have it and run 20% Traxxas fuel in it. But the only problem is that it won't run now. I could seem to tune it to run. It will only fire but I can't get it to run. Can anyone give me some tunning tips for my problem?

 

[scottm]

First of all the engine must be healthy. The way to tell is to take the glow plug out and turn the flywheel with your finger. You should feel some resistance (called "pinch") when the piston is at the top of the stroke. The sleeve is tapered at the top so the piston wedges in to form a tight seal with the sleeve. If there is no resistance the piston and sleeve are worn, and it will be hard to get it to run well. If so, a new piston/sleeve set is about $50.

Otherwise you should get a new glow plug, a glow driver with a good battery, and fresh fuel. Set the carb to the factory recommended settings, and you should be able to get it to start.

 

[Wildcatfreek]

The truck is pretty much brand new.There is plenty of compression. The plug glows bright orange with the igniter I am using. What should the low and high needle be set to?

 

[olds97_lss]

Is it the mach .15?

Typically, 3-4 turns from the bottom on the high speed needle and 1/2 to 1 turn out from flush on the low speed.

Are you getting fuel to the carb? Is your clutch engaged in the clutchbell via a broken spring?

 

[Wildcatfreek]

It is a Mach .15 engine. I went to tun it yesterday and it will now run but only if the glow igniter stays on it. Once I take it off the engine stalls. Plus I noticed that when I open it up full throttle. it also stalls. Should I set the lower speed needle more leaner?

 

[olds97_lss]

I would say it's your high speed that is to rich. Your low speed may be a bit rich as well.

Even though it is a new plug, I'd suggest trying another one just to rule it out.

Are you letting it warm up before you try to drive it? I know that if they aren't above 150 they don't like to stay running with WOT. You should ease it up to 200 then try WOT.

 

[StaticSag]

http://www.dynamiterc.com/ProdInfo/Files/dyn0880-manual.pdf

According to the manual the factory settings are

High speed: 2 1/2 turns out from closed

Low Speed: 4 turns out from close

try this and see what happens.....also I had some trouble with mine when I didn't use the recommended glow plug while trying to run in colder conditions....around 40 degrees or so....try the Dynamite McCoy MC-59 plug and the factory settings and let us know what happens.

Sounds like the stalling is from a too lean low speed....

-Sag

 

[Wildcatfreek]

I had the needles set to those positions and the engine wouldn't run at all with the 20% Traxxas fuel. I still have the original plug in it. I will change plugs today.