Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Hi, my name is***** will be assisting you.
If it is spitting fire back through the carburetor it sounds like you have and intake valve that is not sealing or closing properly. This is the only reason you would get fire back through the carburetor. The intake valve either isn't closing all the way or it is just not sealing good when it does close. The fire coming back through the carburetor is caused when the ignition does fire and the valve isn't closed or sealing it will puff back through the carburetor. I would turn my focus on the valve train in this case.
Thank you it has been a pleasure to assist you.
Please take a moment to rate your experience.