Setting Motor top end, high jet
 

Need some help tuning the top end?

I have the high jet set at 1 3/8.

I’ve read some bits about setting top end but don’t want to lean it out to much,.

Is it best to set it to 1 3/8 & leave it there??

RE: Setting Motor top end, high jet
 

you know if it's too rich the throttle won't respond the engine just sits there sputters, and probably quit on you. the sputtering lessens the leaner the H needle is turned.

i tune mine to the fine line of sputtering and not. at full throttle.

RE: Setting Motor top end, high jet
 

actually sputtering on the high needle is opposite the low needle, it'll sputter on the high end when it's too lean, it won't sputter on high end under a rich condition it just won't develop full power


nzkiwi1975, it depends how is the top end on the rc? is it cracking wide open or bogging out at top end? i've always noticed when lean it'll bog out more so on top end...i've always kept tweaking the top end until i hit that bog spot then backed out about 1/8 to 1/4 turn and if the bog was gone left it alone, i've never really counted turns in it was

RE: Setting Motor top end, high jet
 

it's not a good idea to lean bog your engine

everyone will agree that it's better to be on the rich side than to not know at all


edit; i just realized your at atleast 6800 feet i'm at 800 feet. our opinions may differ.

RE: Setting Motor top end, high jet
 

Easiest way to tell if your high end mixture is right is to do a plug chop. Run it flat out under load and then kill the motor while still revving wot (I adjust my idle so it dies as soon as I throttle off) the plug electrode wants to be a nice milk chocolate tan colour, too rich it will be sooty black, too lean it will be grey..ultra lean it'll be white.