clone carb adjustments

[mark123]

I just bought a new clone and removed gov, filed key for 8 degree advance, put in 18 lb springs. It is hard to start and when I choke it it backfires bit will eventually start. I had to raise the idle to approx 1900, anything less and it stalls. The carb has an idle mixtures screw and was close to 4 turns out from the factory and the stock jet is #70, I didn't check the stock idle jet size. What should I do so I can lower the idle speed without it stalling, I read on another forum to drill main to #90, would this help idle or should I drill the pilot jet larger, if so what size? Should mixture screw be in more?

 

[landuse]

You only need to drill the jets if your engine wants you to. You have go to do a spark plug test and see what colour the plug is. Take the plug out and snap a photo of it and post it here. The colour will tell us if you are running lean or rich.

 

[Rickracer]

Are you sure you went the right direction with the advance key, and did it stay there? I like to use Loctite (Red) Stud and Bearing Mount (between the crank and the flywheel) to make sure the flywheel stays put, won't hurt to put a little on the nut as well. Alternatively,a wee bit of valve grinding compound on the taper can help as well.

 

[mark123]

I installed it so that the flywheel is more clockwise than normal, I used locktite on the nut and torqued to 57ft/lb. As for the sparkplug test, would this tell you anything about the pilot jet and idling / starting? I assume it is more for telling you if your main jet needs changing. The air temp is between -10F and 32F, probably colder than where these engines are made. This is used in a mini snowmobile

 

[firemanjim]

Eerrrrrr..... With 18# springs, you better have a billet connecting rod........ Or you could be putting your kid on a ticking time bomb......