If the ignition is functioning properly, the engine is up to temperature and the plug looks like this, there is way too much fuel. Whether it's jetting, or float level I can't say.
I can tell you this. You can't hurt the engine making the pilot jet or needle too lean while testing at moderate loads. Forget about the main jet, you could take it completely out and you'd barely notice at part throttle. Sort out the Pilot and the needle.
I can tell you this. You can't hurt the engine making the pilot jet or needle too lean while testing at moderate loads. Forget about the main jet, you could take it completely out and you'd barely notice at part throttle. Sort out the Pilot and the needle.