Originally Posted by motoclay

Jammin, Dude, im gonna have to call you out on this one. Everything you state here is right except, there is no way in hell that the thing goes lean as the tank level drops. That is just not right at all. If there is fuel above the pick up, it gets the same amount of fuel to the carb at full or not. That wold be like your car,lawnmower,boat, weed whacker, or go cart goin lean at a lower tank level. As long as it aint empty, it aint goin lean. The motor might go lean as it heats up, and if its set lean at cold start its going to go leaner at opperating temp. Thats why you dont tune a COLD motor. You get it up to opp temp and then tune from there.

However, there is one thing that might could be checked. It sounds like there could possibly be a leak in the pressure line, or on the tank lid. If exhaust pressure is not sealed into the tank its losing pressure and not being able to force it up to the carb.