Repair guides and support for riding lawn tractors sold under the Murray brand name, currently owned by Briggs & Stratton.

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Mower turns over, but will not start

Murray Mower 46800x14A

This problem started last year before the winter.

The old battery was not secured well and slid around and touched the body of the mower and sparked up. I'm not sure if that might have caused something in the electrical system to short? Or this could just be a coincidence.

I replaced the battery and has a good charge.

If I pour some gas, or spray ether into the intake the mower fires up and runs clean / strong but only for about 3 seconds. Then it dies.

Plugs look fine. Not wet. No carbed or gunked up

Gas is passing through the fuel filter and the fuel line is wet where it attaches to the carb.

I disconnected seat safety switch and wedged in small wood shim so connections aren't touching.

What do you guys think this could be?

Answered! View the answer I have this problem too

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The problem may be a partially restricted carburetor.

As gas gets old, it turns to varnish and clogs up the passageways inside the carburetor, not allowing enough gas to get to the engine.

This condition is cumulative. Every time gas sits, the varnish builds up just a little more, like coats of paint, until eventually gas can not flow. It will not happen overnight, but the symptoms can show up over night.

The use of fuel additives, such as Sta-Bil or Sea Foam will not stop this process from happening. They will greatly slow it down, but the gas will still go bad.

When this happens, either the engine simply will not start, or it will not run without the choke on (this reduces the amount of air getting pulled into the engine, changing the fuel/air mixture), or it will run but surges.

Another issue that varnish in the carb can cause is that the varnish may not allow the float needle to seal properly against the seat, causing the flow of gas to not shut off when the bowl is full. The result will be gas overflowing the carb and running into the cylinder, and possibly out the air intake. If the gas gets into the cylinder, it will seep past the rings and down into the crankcase. This will be evidenced by your oil level being over-full and/or the oil smelling like gas.

The only 2 solutions are to either replace the carburetor or give it a good, thorough cleaning.

When removing the carb, make sure to take a good picture, or make a good drawing of where all springs and linkages are attached. This will make reassembly much easier.

Most people believe that cleaning a carb involves removing the bowl and wiping it out, then spraying some carb cleaner through it.

This is simply insufficient.

To properly clean the carb, you must remove it, disassemble it (making sure to remove all non-metal parts), and soak it in a commercial solvent for several hours. Soaking it overnight is even better.

Then clean all solvent off with a spray type carb cleaner, making sure to get lots of cleaner into every hole and passage there is. Pay special attention to the tiny holes in the bore of the carb, under the throttle plate for the carbs that have these holes. Use lots of cleaner. And make sure to wear safety goggles to avoid getting the over spray into your eyes. There will be over spray.

Dry the carb with low pressure compressed air.

When reassembling the carb, make sure to use a carb kit, when one is available for your carb.

Occasionally, even a good cleaning is not going to be sufficient, and you may end up having to replace the carb anyhow. Be prepared for this. I borrowed this answer from Hank.

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Well im having the same problem...I did everything I can think of to do. I change the gas line...put a new fuse to the cylinoid..cleaned the carburetor..frustrated I am....?? maggs

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margaretfhall63, as @mayer, mayer excellent answer provides you with the solution, use it. If engine starts if you spray in carb, a little either or a bit of fresh fuel, the carb is dirty inside and requires cleaning/rebuild.

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Short answer to my fix. To much gas in the fuel tank, gas cap vent clogged.

I had the same problem, motor would crank but would not start. Before having the problem I installed: a new spark plug; new air filter; new gas filter and changed the oil. I was low on gas so I poured what gas i had left from previous week in tank. Not much, may a 1/4 gallon. Mower started like a champ. 2 weeks later I filled the tank and mower would crank but would not start. I assumed I fouled something up with the new parts. After hours of reading and researching. Trying this and that I asked a neighbor if he new of a good small engine mechanic. Neighbor ask if he could take a look. He removed gas cap and the engine started with no problem.

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Thanks allister, worked first time- thank you!!

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The problem is in your carburetor. You need to remove your carburetor and dis-assemble it and clean all internal parts. If you have never done this you may want to watch on you tube or have someone do it for you. After cleaning with carb cleaner and blowing out the jet and ports re-assemble. Not a lot of internal parts but they are small. Pay close attention to tear down and re-assemble the same way. If gas has set in the tank for long period make sure to empty and replace with fresh gas. Engine should fire and run fine. Pay close attention to small springs and how and where they fit. Good luck.

cooklarrym@iowatelecom.net

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