my suzuki m120x engined mower fails to start?

Sounds like the float in the Carburetor is stuck

This results in the fuel not filling the bulb correcctly which is why it will start and run for about 10 secs then slow down and stop.
Pretty common fault in small engines after being dropped.

You will need to pull the carbi and reseat the float.

Note - If it started there is nothing wrong with the magneto

laserguidedbrick
January 2009

This mower is so tough that whatever has happened will be slight in my opinion.

Does it have a spark if you take out the plug and then lay (with its spark plug cable still attached) on the cylinder fins?

Set it up so you can see the plug spark gap and then pull the starter cord. You should see a spark at the plug. If not, suspect that the engine cut out mechanism is damaged. On mine (which is ancient) it has a simple little shorting circuit down by the engine. I can't say how more modern ones stop the engine, but mine has to have the throttle shut right off and then a bit more and a small earthed blade comes in contact with a wire that kills the spark generating system. Check right through that cut out system and see if you can solve the matter. If you have a spark, then check for fuel supply. There is little else to go wrong with a tough old thing like this.

I have one which lives outside in the rain and has done for over ten years. I had not started it for three years up until this morning. I have been cutting back brush and found it again in a bush that has grown up around it. It is completely uncovered and open to all the weather and filth. It was soaked and covered in leaves and soil. I poured a little petrol into the air intake and pulled the cord. It started third pull.

tony
December 2007

This mower is so tough that whatever has happened will be slight in my opinion.

Does it have a spark if you take out the plug and then lay (with its spark plug cable still attached) on the cylinder fins?

Set it up so you can see the plug spark gap and then pull the starter cord. You should see a spark at the plug. If not, suspect that the engine cut out mechanism is damaged. On mine (which is ancient) it has a simple little shorting circuit down by the engine. I can't say how more modern ones stop the engine, but mine has to have the throttle shut right off and then a bit more and a small earthed blade comes in contact with a wire that kills the spark generating system. Check right through that cut out system and see if you can solve the matter. If you have a spark, then check for fuel supply. There is little else to go wrong with a tough old thing like this.

I have one which lives outside in the rain and has done for over ten years. I had not started it for three years up until this morning. I have been cutting back brush and found it again in a bush that has grown up around it. It is completely uncovered and open to all the weather and filth. It was soaked and covered in leaves and soil. I poured a little petrol into the air intake and pulled the cord. It started third pull.

tony
December 2007

have you checked to see whether the cut out switch which is normally operated by the dead man's handle , has become damaged or mal adjusted?

David Mounteney
July 2007

It is possable when the mower was dropped the key that keeps the mower in time was damaged. This key is usually alumunum and can be replaced. You will have to pull the pull rope cover (or engine cover) off and flywheel, on the flywheel shaft there will be a groove and the key, sometimes the key will be stuck in the flywheel. Be sure to replace the key with a like kind and almost any hardware store has them, if not a lawn mower shop will.

Virginia
June 2007