I just acquired a Walmart special mower from a friend of mine. It has 3.5HP B&G motor on it. When I got it it would start but only run for a few seconds about 30 seconds and shut off. If I pushed the primer bulb it would keep running. So I pulled the gas tank and carburetor off. It is a very simple set up. I unscrewed the carburetor off of the gas tank and sprayed it with carburetor cleaner. When I put it all back together same thing. So I took it back apart again this time removing the gaskets and really spraying. Didn't really see any dirt but sprayed anyway. This time when I put it back together it now runs without shutting off. Only one catch it doesn't run correctly. There are no carburetor adjustments like screws or anything. When it runs it runs low and high consistently.........not at one single high rpm like it is supposed to so that you could actually cut grass with it. Is there something else I should check now? I put a new plug in it, new gas, cleaned the flywheel which really wasn't rusty or dirty. The mower is only 3 years old and for the most part in like new condition. Is it still carburetor problems? Air filter is cleaned too. Thanks ahead of time for your help.