my mower starts and runs on carb spray but not on its own. the primer does not squirt fuel. i removed, disassembled, cleaned with carb spray and compressed air, verified needle and seat are open with float down and closed with float when at top of its travel. fuel is supplied to the bowl as verified by gas running out out plastic bowl when fuel hose is removed. seems like if i could prime it it should run. it was running and starting great one weekend, wouldn't start the next. help please.