When I use the self-propel bar on the lawn mower, it comes close to cutting off, sputters and almost backfires. If you let go of the bar, everything comes back to normal. Spark plug gap is calibrated corectly. Looking for ideas on how to diagnose the problem or if anyone else has seen this. Thanks!

Hi,
Not sure and cannot look it up without the nine digit model number (begins with 917.) Look for something picked up that may be interfering with the drive system.
Do be sure to observe the air filter or spark plug UP rule of turning a mower on its side.
Peace,
Clarke

Clarke - thanks. My dad told me this afternoon that he just purchased this mower 2 months ago. I told him to return it :-) Thanks for the feedback though. This was my first time on this site - seems like it could be really useful and I could learn a lot. Thanks for responding.

Hi
Yes, you have a two year warranty and probably a 90 day return policy. Thought it might be fairly new because the "650" number rating system is the new Briggs engine rating that is based on an engine's torque rather than horsepower.
Peace,
Clarke