I've had a real problem starting the engine for a long time. Would crank but not fire up. (sometimes would fire and start when I turned out the air/fuel mixture screw about 6 turns, but I can't run the engine long at this setting) Checked Woodruff key (good), spark (good), compression (150 psi on both cylinders). Today I thought I'd check out the primer solenoid, and found that there's no fuel coming out of the choke fuel lines, neither when the primer should be activated on the keyswitch or when the red lever is set to manual. (this lever seems very loose ). I can take this whole unit apart, but what should I look for?