I bought some mechanic in a bottle at Home Depot on the recommendation of a family member who is a good small engine mechanic. The stuff flat out WORKS. I had a 3.5 hp Briggs mower that suddenly started running poorly and surging. I use fresh E zero gas and stabilizer so the fuel should be ok. I put a generous slug of MIAB in the tank and mowed the lawn. The mower smoothed out and has run fine ever since. I know that everyone has a favorite carb cleaner, just reporting on one that worked for me