Walbro Carb WT-685
The WT-685 is on a Troy Bilt TB90BC brush cutter with external purge/primer bulb. Machine starts up and idles great. New fuel lines, new plug, cleaned carb (sprayed with non-chlorinated brake cleaner and WD-40). Decarbonized engine and muffler. Fuel filter clear. Checked ignition air gap (ok). Problem is...will not accelerate, at all. Feathering the throttle only raised the rpm's very little. So...is it 1. bad diaghragms and/or fuel pump (it has the blue one) or 2. Just need to tweak the high or low mixture screws (D- shaped heads)? Before all this done, machine would NOT start, but starts right up now. Thanks.