cetme308

Hey, got a new Stampede nitro a couple months ago but life blah blah and now I'm trying to break in the engine. I'm not all that experienced in nitro so I don't know if these are real issues or just part of the process. The problems are mostly that the engine will die pretty much at any time. Don't matter if the engine is cold or been running (off and on) for 30 minutes. At times it will idle fine and others it will die quickly. Sometimes the engine will fire right up and stay running and others it will die just as quick as it starts and that could happen for the next five minutes. I do the priming and can't really say if that makes it start or does any better of a job in keeping it running.

If this is all part of the process and I shouldn't really have these issues later on then great but I'm a paranoid person and like to, kinda, know what causes things to happen.

flyinwalenda

My Feedback: (5)

The engine will run terrible for the first 6 tanks or so of fuel as it breaks in. As you break it in you can adjust the hs needle a little as you go and after break-in you can adjust both the hs and ls needles to obtain a good tune.
Make sure you are following the procedure in the manual and do not push it. Break-in is a very boring process but when done correctly the engine will run and last for a long time.

1QwkSport2.5r

The needle settings as it comes out of the box is most often too rich for the engine to run right. Too rich is not a good thing as it doesn't allow the engine to heat up which is necessary for it to break in. Lean the low speed needle 1/8th turn and try running it again. If it's still not idling well and quitting when you hit the throttle, try leaning the low speed another 1/8 turn. After a total of a 1/4 turn leaner, use smaller increments until it will idle for about 10 seconds and still allow you to punch it and have it stay running. The top end can stay a bit rich as the idle needle controls fuel flow for about 75% of the throttle. As long as you don't run it too lean, babying it just prolongs the actual break-in of the engine as the higher rpm is what seats the bearings and conrod bushings. The piston-liner break-in on their own provided the engine is operated warm enough.

cetme308

Thanks for the reply. Currently the weather is hot, 80s, with various levels of humidity. I don't go out when the humidity is bad but am trying to at least get one tank in at night if I don't break out in a instant sweat.

I'm doing no more then half a throttle for less then three seconds at a time as I fear the engine will cut out. I'll be looking forward to that seventh tank.

Edit: Just seen your post 1QwkSport2.5r and thanks for the info. Would running too rich cause the engine to die more often? I will check and reset the needles if need be and then do the low needle as you instruct and go from there.

1QwkSport2.5r

Too rich and the fuel tends to form larger droplets and drowns the plug element. An easy way to tell if your idle mix is too rich is keep the glow driver on the plug and drive the car around awhile to warm it up some. If it quits with the glow driver on it, it's either way too rich or way too lean. Another tell-tale is if you pull the glow driver and the rpm drops.

If you go back to the factory settings (which you likely won't need to do), plan to lean the needles at least 1/8-1/4 turn right off the bat. Hot humid air will require a leaner mixture than cooler/drier air.

cetme308

Thanks for the info, I'll try that out this week.