Learned something new

tinknal · #1 03/10/11, 03:21 PM

You motorheads prolly already know this, but........

The switch on a chain saw doesn't turn it on, it turns it off.

My old stihl wouldn't start. I discovered it had no spark. The switch has been bad for some time. Usually the switch wouldn't turn off so I would choke the engine to kill it.

Anyway, I took the switch off and now it runs. Apparently what the switch does is ground out the magneto?

Ray · #2 03/12/11, 04:40 PM

its like the old metal tab to kill a lawnmower, when you hold it to the sparkplug, it sends the fire to ground instead of the spark gap where it is needed to burn the gas in the cylinder to push the piston back down. no fire, no explosion, no run. best wishes, ray

tinknal · #3 03/12/11, 05:17 PM

Quote:

Originally Posted by Ray

its like the old metal tab to kill a lawnmower, when you hold it to the sparkplug, it sends the fire to ground instead of the spark gap where it is needed to burn the gas in the cylinder to push the piston back down. no fire, no explosion, no run. best wishes, ray

Yeah, I forgot about them. They always kinda half scared me. I seem to remember getting zapped once.

How Do I · #4 03/12/11, 07:09 PM

Hmmmm. This makes me wonder. I have an older craftsman chainsaw out in the shed that won't start. Doesn't have a spark. Last time I used it, it was running fine. Then it revved high for a few seconds and just died. Hasn't started since. Could this be something to look at?

Ray · #5 03/12/11, 09:19 PM

usually when a chainsaw, lawnmower or other small engine like that revs before it dies its because its running out of gas and is leaning out, pulling more air causing the engine to get more power right before it dies. I'd check the fuel and see if something is going on there first. If it was the kill wire grounding, it would just die, dead, and never start again. I had a kill wire come off and ground in an outboard once 3 miles downstream, zero degrees, 10:30 PM, made a rough night out of it, wading chest deep pulling everyone back up stream to the trailer. was cold to the bone. then to find it was just a wire came off and grounded it. DAM# anyway I always check that now of coarse it will never happen again, ha ha, best wishes, ray

tinknal · #6 03/12/11, 10:29 PM

Quote:

Originally Posted by How Do I

Hmmmm. This makes me wonder. I have an older craftsman chainsaw out in the shed that won't start. Doesn't have a spark. Last time I used it, it was running fine. Then it revved high for a few seconds and just died. Hasn't started since. Could this be something to look at?

Ethanol fuel can rot out the rubber parts in the fuel system. I agree with Ray, something is going on in the fuel system.