I purchased a craftsman push mower 2 years ago. It's be stored inside and been used on our personal lawn for 2 summers.

A week ago it ran wonderfully, then it started running poorly. Eventually getting to where I couldn't even cut the grass. I'm not mechanic by any means, but have tried the following:

  • Cleaned air filter
  • Dumped out old gas and replaced with new.
  • Took the Carburetor apart and clean the entire thing.Sprayed parts with brake cleaner, as that's what i had as opposed to Carb cleaner.
  • removed spark plug and screwed back in.

It starts every time on the first pull, however it just runs weak and chugs a long. I noticed that when I tip it back - meaning front wheels in the air, it runs significantly better. When I put the mower deck back level, it sputters along. The oil level appears to be low if anything. Not significantly, just lower than suggested.

any help would be appreciated.

  • 1
    Typically carb not cleaned properly. On my honda carbs circa 1980s I can think of 8 different orifices I spray through. I also usually dip the carbs in carb cleaner even if for a short time. I also learned name brand carb cleaner works better than the generic stuff so i use the name brand stuff internally and generic stuff externally. Blowing with air is also needed after spraying. If you are not practiced at it, just buy a new carb and see if it fixes your problem.
    – Damon
    Commented Sep 11, 2017 at 8:17
  • 1
    If it runs like normal when you tilt the mower back, then you have a carb issue. Could be a float issue, could be a small fuel or air restriction as well. When level the float might not be moving freely enough to allow the fuel to siphon in at the proper amount. I agree with above...buy a new carb and try that, they are usually cheap.
    – Jeff Cates
    Commented Sep 22, 2017 at 18:54
  • any chance you hit something hard (ie rock) with the blade? Possibly sheared the flywheel key.
    – agentp
    Commented Dec 1, 2017 at 3:15

1 Answer 1


How far apart did you disassemble the carb? Did you clean the metering valve assembly? these are usually super tiny that you need a single strand of stranded wire to get in there and clear the ball bearing or check valve parts.

If you provide the model # I'll try to find the engine diagram and point it out.

You also want to check the float and make sure it is seated correctly and no liquid inside of it.

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