Hello all. I have a Craftsman model 917370561 lawn mower with a briggs stratton engine. It began misfiring, so I gave it a tune up (change oil, filter and spark plug). It continued misfiring and hard to turn on so I rebuilt the carb with the Briggs Stratton Carb rebuilt kit and also changed the primer bulb. It still misfiring and hard to turn on. I actually have to prime it 6-10 times for it to turn on and then misfires as it is on. If I turn it off and try to turn it right back up, i have to reprime which was not the case before. I then removed the filter housing and primed it and did not see any gas coming out from the tubing into the carb throttle body chamber. Actually sometimes it does come out and other times it does not. Any idea what might be causing this? Do I need a new carb or something else? Any info greatly appreciated. Thanks