how lean or rich??
 

hi guys and girls, i know that in adjusting the idle mixture screw u have to lean out the engine. but in piston engines leaning an engine can burn valves and mess up cylinder walls so how lean or rich does a 7 have to run on stock form?? and wat would be a good mixture for a slightly tuned 7??

First of all, with the idle mix screw you're only adjusting idle mixture, i.e. up to less than 2k rpm. It is impossible to damage the engine by leaning out the idle mix. It'll stop if you screw it in all the way, but it won't damage it. If you have a way of measuring a/f mix, about 8:1 at idle and progressing towards 12:1 to 13:1 at max rpms will do for your stock NA engine.

ok thanks man.