Our Ariens snowblower, one year old, has a 195 cc Tecumseh engine, OHV type. It also has a fuel shut-off valve between the fuel tank and the carburetor, which I use. When I'm done working, I shut off the fuel, & let the unit idle until it stops running due to fuel starvation. So far, it starts on the first pull, after priming manually. I have yet to use the "plug-in" electric start feature.

I don't know of any fault in the primer that would cause flooding unless it was pushed too many times.

If the carb mounts on the left side of the motor, those can sometimes be empty of fuel for no reason. Loosen the bowl nut before using it and see if gas seeps out. Tighten again and prime normally and start. 1/2" socket.

sadly there is no room to install a fuel shutoff on this engine. i would have done so long ago if there was. i have constant fuel issues with mine.

It sounds as though you are correct in thinking that fuel leaks past the float valve at times. Is he trying to avoid getting into the carb repair? As lawnmowerdan had noted, there isn't much room to do an inline valve the current line configuration. Maybe a 90 degree valve like a Honda GCV would use?