Originally posted by Z00M
Hope you have better luck with yours than I have with mine.
I can't get the engine to run properly without seeing temps in the 230(idle) - 270F(after running) range. If I go to a cooler setting it is way to rich to rev out and usually stalls after idling for 3 secs when the throttle is opened.
I've tried the factory settings (LSN 4 turns out, Mid fulsh and HSN 4 turns out) but these are too rich for the motor to rev and it idles at 230F. I have tried all manner of needle settings but it's not happening for me. I pulled the carb to pieces, replaced one damaged o ring, sealed every part of the carb I could and still it seems like it has an air leak at idle.
I didn't have this trouble with either my Force 15 or the Picco Omega XT I was running before, although these were both rotary carbs.
I bought a couple of second hand motors and these are going to have to do since this STS motor is very unfriendly. I want to race, not spend frustrating days dicking around with the settings that I can never get right.
I wouldn't even want to sell this motor to someone else as I couldn't handle selling someone a dud.
Zoom
Try add extra head shims and run #7 plug for start, you should see the different.