17" 32cc weed trimmer Neighbor gave me this. I don't think it has many hours on it. I can't get it to start (neither could he). I've been through the carb several times with carb cleaner and compressed air including the removal of the welch plug. I snuck it into the dishwasher once to get some heat applied to it. It has fresh 40:1 gas. Plug has a nice golden brown look to it. the carb is a walbro wt 434 compression is 100psi piston and cylinder look good from exhaust side removed the fuel filter temporily just to make sure that was not the problem. I stripped this thing down to bear bones and cleaned with carb cleaner and compressed air (removed welch plug, fuel screen, L and H needles, etc). I can get it started by holding the throttle wide open and pulling the starter. It runs good mid and above, but it won't idle on its own. Played with the L and H screws. Maxed out the idle screw. No luck. advice?