I have a Bolens simple rear bag push mower I am repairing for my daughter. I have been working on this style motor since the 70's when I as a kid. Anyway, I have an issue, and it is the second time I have encountered it with this type of Briggs. (Simple Tank mount carb) I went through this thing and installed new diaphragm and gasket, taking great detail on doing it right, and a thorough cleaning of the tank, etc. Also checked the gap on coil, new plug, oil change, etc. Not much else needed on this style motor. It had been searching up and down, as briggs typically does when dirty, and the brake cable was in poor shape so it was replaced as well. So, here is the issue. It starts right up. runs perfect for about 30 seconds, then starts sputtering bad like it is running out of fuel. If I tilt the mower back towards the handle, it runs perfect. What gives? I have double checked, and triple checked the carb assembly, recleaned, and recleaned the tank. I actually washed the inner part of the tank with hot soapy water, and rinsed it, and left it in the sun to dry for a day...as I always have. It is bizarre to me that it will not run smooth unless I tilt it back...oh, and the tank is full. I am human, and as such, I am capable of being stupid and overlooking something, but this has me puzzled. I have considered a faulty coil. and that will be my next step, but wow...any ideas?
