Hello Folks, I have a 1980 / 5hp. Briggs snow blower with auger and exhaust shoot. I just thoroughly cleaned, and soaked the carb, and then reassembled with a new fuel pump kit [diaphram & spring]. It now runs, after priming it through the spark plug hole. After its warm, 1 in 10 tries pulling the cord will start it. When its running... it will pull through the heavy snow 6" to 8", but then all of a sudden... with NO load.. Stall. The spark is good, and steady. However, in the Past, several years ago, I had a sticking Intake valve that would preclude the engine from even starting at all. The carb gasket to the fuel tank is new, and the carb's Intake gasket to head is Good. All screws, and bolts are tight with No air leaks. Calling on All Experts to solve this Mystery. Please, Advise as to what the possible problem/s might be. Thank-You-All, Jim.

All this time I thought we had some Experts out there. HAVE ANY OF YOU HEARD OF A "MAIN JET"?? Well there is such a thing behind the needle and seat assembly! I discovered it [Brass plug with hole], Removed it, Cleaned it, Reinstalled it, and Now the engine runs with Apparently No problems.
Thanks-To-Me, Because of my couriousity, I can now remove snow again. Thanks, Nitro-btu.