If you've got your gas tank off but still want to test run your engine, run a temporary line to the carb from a test reservoir mounted higher than the carb to let gravity feed the carb.

This is an oil / fuel mixing syringe for 2 cycle engines that can be purchased for under $5 at most automotive departments and parts stores. ¹⁾

You'll need a 1/4“ hose clamp and app. 3 feet 1/4” fuel line. Drill a small hole in both the top and bottom flange of the mixer to prevent vacuum / suction problems. 2)	Press one end of the fuel line onto the fuel mixer, tighten the hose clamp around it and the other end to your carb inlet. 3)	Fill the mixer with gas, tap the line to get the air bubbles out, insert the plunger, and hang the round end over the front brake lever. Works like a charm, no mess, and you can run the engine for several minutes while freeing up one of your hands. 4)