Hi,
I'm trying to break in a new engine and am having loads of problems. I had starting problems, now I've managed to get 3 tanks through it, but it starts revving uncontrollably. It revs high when I close the carb (?? yeh really !! ??), and slows a bit when I open it. I'm noticing fuel on the chassis beside the engine. Do you think I have an air leak ? Where could it be from ?

Any ideas would be really appreciated.

Regards,
32819toon

Ya it sounds like an air leak, try this to make sure
http://www.rchobbies.org/engine-tuning.htm

as for the fuel on the ground, it's most likely oil, not fuel. This is a good sign meaning there is plenty of oil to lubracate your engine. This is normal because you always run rich during break in.

once break in is done you can lean out your engine to get better perforamnce.
This is for the savage and t-maxx, but is the same for all nitro engines

http://www.youtube.com/watch?v=oSmMzpZM_As
http://www.youtube.com/watch?v=BJFsJ...elated&search=
http://www.youtube.com/watch?v=pEGjE...elated&search=

hope this helps!

Thanks dub88, excellent article, I'm gonna give that a try. I have the HPI DVD which is good, but it doesn't tell you about faults like this. I also have the Joel Johnson one aswell which give more tips and detail.

thank APOLLO
I got this artical off his guide from this other forum (which is much better than this one)http://www.rcuniverse.com/forum/default.asp?fh=1

it can also be a lean low speed needle,try richening it up a 1/4 turn and see if it gets better.

i have the same problem but i already broken it in (its a pull start)

I think I've found the leak, it is from under the glow plug. Fuel or oil is bubbling from under the glow plug even when the plug is tight. How can I sort this out ?

Hi,
Got it idling reasonably by messing with the needle, although it still sounds really rough. I'm still a bit concerned about oil / fuel bubbling from under the glow plug. Anyone have any ideas about this ??

If it's a turbo plug, pull the plug and put it back in again making sure it's snug. If it still leaks try a new plug.

If it's a standard plug, do the same, but make sure to use a new copper washer...or put a new plug in with a new copper washer.

It won't run right with a leak around the plug. It's not reaching full compression.

Thanks Terry, I'll give that a try.