About that green goo. There is an air passage that emulsifies the fuel going to the idle and transition jets. If the goo (resedue from evaporated fuel) managed to clog this air passage, you will be pulling pure fuel through these jets. At idle, the idle screw has enough travel to correct the mix but, when running above idle but less than maybe 1/4 - 1/3 throttle, you are running on the transition jets. Should the air bleed passage be blocked, you could be pulling pure fuel instead of the air/fuel emulsion and that would make the mixture very rich.
If the mixture is nearly normal when you open the throttle wider and run the engine at speeds above 3500 RPM (with a load of course!) the main jet, slide, etc are probably working fine.
