Murray B&S 402707 lawn tractor won't start


Old 06-16-08, 09:54 AM
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Join Date: Jun 2008
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Unhappy Murray B&S 402707 lawn tractor won't start

Hey guys - my Murray B&S 402707 lawn tractor was running ok last year...on my last mowing day, it sputtered to a stop on its own. I didn't try to restart it then, I just put it away.

Today is the first time I tried to start it this year, and it won't start (big surprise...). It has spark at the left side spark plug (not real bright, but I figure it's not supposed to look as strong as a car)...and I didn't check right side yet. I think I can see gas sitting in the bottom of the carb - shouldn't it be going somewhere? The battery is fine, and the motor turns fine. I've been told to pull out the spark plugs and put a teaspoon of gas in each cylinder and see if it will run for a few seconds. If that works, what does that tell me?

Any ideas you have about deciphering/fixing my problem are greatly appreciated.

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Old 06-16-08, 10:50 AM
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Location: Marion,Al.
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That little test will tell you weather or not fuel is being pumped into the cylinder.Which it sounds like it's not.Take the top off the carb.and clean good,all the holes and everything.Then take the drain plug out of the bottom of the bowl and clean inside really good too.Be careful the plug might have a spring and ball behind it that will come out.
Old 06-18-08, 10:31 AM
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Join Date: Jun 2008
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Cleaned out the top of the carb and the bowl - bowl had a little bit of slimey, light-colored stuff in it. Put carb back together, left the air filter off.

Now when I try to start it, there's gas shooting out the exhaust and blowing back up through the carb. Still no start. What could that be? I read somewhere it could be a piece of dirt lodged in a needle valve or seat, but I'm a beginner at this, so can you explain what I should be doing?


Last edited by MasterTempo; 06-18-08 at 10:57 AM.
Old 06-18-08, 11:07 PM
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The float could be stuck, or dirt in the needle/seat area, or the float may be full of gas. Take the top off the carb again and check to be sure the float moves up and down freely, the needle is in place and in good shape, and there is nothing under the needle.

You might consider taking the carb to a shop and let them soak it in a carb bath and recondition it. It sounds like yours needs the thorough treatment and rebuild.

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