I have a 4 hp Briggs and Straton lawn mower engine that won't start at all. I've changed the spark plug, air filter, carburetor float valve and seat. Gas is also new. Can't even get a sputter out of it. Local repair shops are about 5 weeks out so that's not an option. Any suggestions would be appreciated.

  • Welcome to Motor Vehicle Maintenance & Repair! Jun 16, 2023 at 0:50
  • You're not forgetting to squeeze the safety bar, are you? Also known as the "bail". If you are squeezing it, check that the linkage to the safety switch is properly closing the switch, and/or temporarily jumper the safety switch to see if that's the problem.
    – MTA
    Jun 16, 2023 at 1:01

1 Answer 1


First thing to check is whether you are getting a spark at the spark plug.

Remove the spark plug and hold it against the engine with the HT lead still connected to it. Keep it away from the spark plug hole where the fuel mixture will be. Try to start the engine (make sure the safety cutout is in the run position as mentioned by MTA in the comments). Is there a spark at the plug?

If not, check the safety cut-out circuit and also the ignition coil.

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