QuestionI have a craftsman 6.0 HP, 21" Briggs/Stratton and Tecumseh carb, push mower. Model# 917-388391
Late last mowing season it started running rough after 30 minutes of cutting then would slowly even out and finish cutting the last 30 minutes. I figured I'd just wait til next season to replace the sparkplug. This season, I've replaced the sparkplug, cleaned the carb, did a carb kit and replaced the coil. Although the engine runs much stronger when first started it deteriorates much quicker. Within 10 minutes it starts running rough, coughs, sputters, backfires and eventually dies. It is difficult to restart, but will restart after a couple of primings, then it cycles between 1 minute of running rough and backfiring to a minute of running fine, eventually though it will die again. What used to take an hour to cut now takes 2. Thanks for any advice.
AnswerOk lets back up here, you said "6.0 HP, 21" Briggs/Stratton and Tecumseh carb," If it's a Briggs engine It can not possible have a Tecumseh carb on it, it would have to have a Briggs carb on it. Second, why did you do all the parts changing in every direction? If was either a ignition problem, or fuel problem, assuming the engine has good compression, and the flywheel key is not sheared. Is it possible something was hit during mowing, that may have shear the fly wheel key? We have to start with basics first. 1. Is there spark, if so is it a good strong blue spark? 2. Is fuel present, and getting to the cylinder? I doubt it's a spark issue, the coil never usually goes from a good spark back to a bad one in a matter of minutes. This acts as if it's a fuel problem. When you did a cab kit what parts did you replace? Did you totally disassemble the carb, meaning removing the jets, and forcing carb cleaner through each jet passage? Did you replace the float needle seat, and install the seat with the ridges facing down, and seat the seat all the way down in the hole? .......Tom
