Hey Chris,
It sounds like it could be one of two problems, you said it was bogging at wot and running real hot, reset the high speed needle back to factory and start to retune. It sounds like your high speed needle is to lean. You said you have not ran for a couple of weeks, the air condtions could of changed (humidity). Did you clear the fuel lines of fuel and use afterrun oil, if there was any fuel left in the lines and engine, it could of gummed up. When your truck wants to take off when the throttle is in the nuetrual postions could be caused by the idle is set to high or you have a broken clutch spring inside the clutch bell. To set the Idle pull the air cleaner off and look into the carb. There should be a 1mm gap or opening. You can fine tune this while the engine is running. I took a look at my Nemesis and checked the first speed gear and it was not loose like yours. I would have to see pics of the gear to see exactly what it is doing. It could be a bad bearing or the t bolt could be loose.