Jet Size needed for a very mild GX160

[brettdn]

I recently installed OldMiniBikes's 8 inch header and angled air filter on my GX160, I already have a 140 emulsion tube and a .36 jet installed and the motor runs fine but the spark plug is really black and I am assuming it is running rich, this was both tested on a NGK BRP6ES and an Autolite AR3910X. Should I just go back to a stock jet and see if I get a better color or should I go back to the stock E-Tube? If you need more information on specs I can provide more

Thanks

 

[David wulf]

First are you doing the plug reading correct , get the motor hot install new plug take off , run her wide open and shut her off . Any idling will blacken the plug and give you a false reading .

 

[brettdn]

I'll pick up a couple new plugs and give it a try again, I think my problem was that I let it idle after I maxed the throttle!