When engaging the blade to cut, with the throttle on high, the mower comes to a practical stall. To keep it from stalling I have to quickly disengage the blade. I've checked two brake pads and they both release when the blade is engaged and they clamp the belt when disengaged. The belt seems a bit loose but then I don't know how tight it should be either. I have a very weak battery that usually has to be jumped to start, but once started, the mower runs fine. I've checked for clumps of grass and can turn the blade by hand as well. Anyone ever had this problem? Thanks for your help! Tony

I believe those pads are adjustable. You say they do release but I suspect they release just a bit too late and stall the engine. The belt should be loose if the blade is disengaged but totally tight when engaged.