Small Engines (Lawn Mowers, etc.): switchs, resistance measurement, wireing harness

Question
sometimes my l120 will start rite up and sometimes not. it is at the point were it does not start at all. it has a new coil or magneto and a valve adjustment.  the mechanic said it was a probably a switch. he also said there were three. he also came across like he did not know without guessing. i have no faith in this guy at all. it seems to be the case in the opinion of the local yard pros. the next guy is a good bit away. the question is witch switch would do that and what is its name. i would test it my self and replace it once started it runs like a top. thanks in advance for your help

Answer
The typical 3 switches are a seat switch, clutch/neutral switch, and a blade engagement switch.

The switches are very simple on/off type switches, like a basic house light switch.  The switches allow current to flow or stop.

If you have a simple voltmeter with a continunity tester or resistance measurement you can check each switch.  You can find the switches just by following the wireing harness. Some mowers use a neutral switch mounted in the transmission but the wires will still be sticking out of the transmission.  One switch may be a dual switch, it will have 4 pins.  Same switch just usually one side is open and one side is closed.

Do you have a multimeter?

Eric