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View Full Version : Craftsman 20 HP B+S engine won't start and stay running


Roebuck1998
Apr 27, 2009, 04:32 PM
Craftsman Electric start mower (Model No. 917.270930) is 7 years old and has been maintain as per manufacturers specifications. The trouble is that the engine will start and run for about 30 to 40 seconds and then cut out. When I try to restart the engine is becomes flooded. This has been happening over the last two seasons. When I take the cover and air filter off the compartment is full of gas and when I turn it over gas flies out of the carburetor and becomes more flooded.

When I spoke to a local Briggs and Stratton certified repair shop they stated the I have probably been running ethanol / flex fuel which makes the engine run rich. He suggested that I completely drain the gas and put in regular gas (non ethanol). The gas tank is under the seat on the tractor and I am not sure what would be the best way to drain the system.

The tractor has new plugs/gas filter/air filter and has a new battery. I have plenty of crank but after the initial start of 30 seconds or so - no go. Any suggestions would be appreciated.

21boat
Apr 27, 2009, 10:22 PM
It sounds more like the float is stuck or the float needle valve seat is stuck and not shutting down the gas supply to carb bowel

Roebuck1998
May 2, 2009, 09:07 AM
It sounds more like the float is stuck or the the float needle valve seat is stuck and not shutting down the gas supply to carb bowel

I think you are right and the float/needle is stuck. When the throttle is shut down the float is closed and when you just move the throttle a half inch the float opens all the way open - it does not adjust like you want it to.

How would you recommend that I attempt to fix this?

21boat
May 2, 2009, 12:20 PM
The seat may have some dirt in it. As long as the float will float I would use carb cleaner in the needle and seat valve and clean the sediments out of the fuel bowl.

The worst would be get a carb kit.

You could disconnect the fuel filter and drain out of that line if the filter is low enough. Or buy a cheap siphon to drain the tank. The tanks are a pain getting out or get under it to pop the line another pain.