New Engine Problems
07-12-2010, 03:30 AM
New Engine Problems
I have recently bought my first nitro car (schumacher rascal 2) after a few years messing with battery cars.
I have broken the engine in following a online guide from schumacher. Now the engine runs reasonbly well, but something is wrong I feel.
When I start the engine from cold, it takes a while to run properly I think, and once it is warmed up it seems ok. On acceleration it seems to smoke a lot, but does accelerate quickly but then at higher revs it really does fly.
After a few fast runs, when i try stop the car, the revs are really high, and I cannot keep the car still. But when I let the car cool, start up again the revs are fine again.
Only when the car is up to temp, it revs too much at idle.
My gut feeling is that the high speed needle is too lean and the low speed is too rich?? But being a beginner I would rather some pro advice!
Thanks for your help.
07-12-2010, 09:23 PM
RE: New Engine Problems
These should aid you in tuning a bit.
http://www.xenonproject.com/tuning-y...gine-a-10.html
http://www.rccartips.com/rc-nitro-engine-tips.htm
http://www.ultimaterc.com/forums/showthread.php?t=94808
A good way to set your HSN is to do a high speed pass by you (when the engine is up to temp), and let off the throttle right next to you. If it revs up before idling down the HSN is too lean.
The best way to set your LSN is to do the famous pinch test. Pinch the fuel line about an inch and a half from the carb, and start counting 1-1 thousand, 2- 1 thousand, 3-1 thousand... The engine should die between 3 and 5 1 thousands. If it dies sooner, its too lean, longer than 5 it's too rich.
Idle adjustment... After you get the HSN and the LSN set, do a high speed pass (to let the carb adjust out). Bring it in and let it idle, if it's racing your gap is just a bit too big. After each adjustment on all needles, make a couple high speed passes to let the carb adjust itself...
Read everything you can on tuning... Good luck
07-13-2010, 02:10 AM
RE: New Engine Problems
Thanks for your reply, I took it out for a blast last night and had a tinker!
I warmed the car up and yet again the revs were racing on idle, So I richend the LSN and HSN and the revs stopped racing immediately. I did a few passes and the car was slower than its been, but to be honest I think ive been running too lean all round!! (whoops)
After reading a lot on tuning I followed a guide, which told me to lean the HSW until the performance at top speed got worse, so I did and I got to a stage where the engine was popping slightly at top speed. So I backed it off 1/8 and I seems to run fine now, with a good amount of smoke.
Did the pinch test and it seems to die after about three seconds, not sure if this is enough time though??
I think I would rather run it a bit rich for now, incase I blow it!! I have ordered a temp gun in the mean time!
Thanks again
