Check it out, but most primers on these engines only fill the carb cavities and circulate it back to the tank which is where that fuel line that you plugged would normally go. They don't actually pump fuel into the engine. Thats why these engines, when they're in weedwackers and chainsaws have the primer as well as a choke. You might be able to salvage a slide choke from the local saw shop from his junk pile. it's a plastic assy. that bolts to the face of the carb and held on with the carb screws. It's a plate that slides over the face of the carb to block off the hole.