Seized chainsaw

[oldballs]

Last winter I had a similar post when my MS290 (20" bar) "quit running" as I was cutting a 30 inch Pine stump right at ground level. After it colled down (it was smoking) it had very little compression and I couldn't get it started again. I took it to a friend who gave it back to me running fine at acceptable compression at no charge. He didn't take it apart nor replace any parts. I really don't know "what happened" nor what he did to it.

Cheers,
Mike

 

[MossRoad]

After 40 years of working around loggers I have never seen or heard of such a thing. Everyone starts and runs full throttle during cold or warm weather. The only saw motors I’ve ever seen seized was due to lubricant failure.

I drag raced a Yamaha RD400 2-stroke twin for about 10 years. Did all of my own engine and carb work. Pretty heavily modified bike. I had an occasion where I pulled it out of the garage, Gave it a kick to start it, the throttle cable did not return and got stuck full open, and it went from zero to a billion RPMs in about half a second, then PINNNG! It stopped. Seized solid. Upon dissection, the cylinders were scored heavily. It wasn't from no fuel or improper lubrication. It was from cold start to high RPMs instantly.

I can guarantee you that the loggers you know never do that to a cold saw. They give it a pull, it fires up to an idle speed, they pop the throttle a few times, wait a couple seconds, pop it again a few times, then go off to work. Those few seconds of warming it up make a huge difference.

 

[jyoutz]

I drag raced a Yamaha RD400 2-stroke twin for about 10 years. Did all of my own engine and carb work. Pretty heavily modified bike. I had an occasion where I pulled it out of the garage, Gave it a kick to start it, the throttle cable did not return and got stuck full open, and it went from zero to a billion RPMs in about half a second, then PINNNG! It stopped. Seized solid. Upon dissection, the cylinders were scored heavily. It wasn't from no fuel or improper lubrication. It was from cold start to high RPMs instantly.

I can guarantee you that the loggers you know never do that to a cold saw. They give it a pull, it fires up to an idle speed, they pop the throttle a few times, wait a couple seconds, pop it again a few times, then go off to work. Those few seconds of warming it up make a huge difference.

Many fire at full throttle, then let idle to warm up. I would still bet that the OP’s issue is due to lubrication.

 

[MossRoad]

Many fire at full throttle, then let idle to warm up. I would still bet that the OP’s issue is due to lubrication.

Sure. Most of the time that's the cause and the first thing to consider. However, someone stated it's the only cause, and it's not.

 

[jyoutz]

Sure. Most of the time that's the cause and the first thing to consider. However, someone stated it's the only cause, and it's not.

OK.

 

[marhar]

If you didn’t run the proper 2 cycle oil mix in your gas, then your saw is now a doorstop.

I agree. Too little oil will cause one to run hot (I made a dumb mistake in measuring and know). I made my mistake while cutting a cherry stump with a dull blade.

Take the plug out and see if you see fine metal shavings. If you see metal shaving you have a saw to part out.

 

[jyoutz]

I agree. Too little oil will cause one to run hot (I made a dumb mistake in measuring and know). I made my mistake while cutting a cherry stump with a dull blade.

Take the plug out and see if you see fine metal shavings. If you see metal shaving you have a saw to part out.

I have always tried to err on the side of extra oil. The only impacts of a slightly heavier oil/gas mix is a fouled spark plug and slightly reduced performance.

 

[MossRoad]

I have always tried to err on the side of extra oil. The only impacts of a slightly heavier oil/gas mix is a fouled spark plug and slightly reduced performance.

Too much oil in the gas and you can get a contract with the county fogging for mosquitos.

 

[jyoutz]

Too much oil in the gas and you can get a contract with the county fogging for mosquitos.

True. I use slightly more, not an excessive amount.

 

[RandyT]

I have always tried to err on the side of extra oil. The only impacts of a slightly heavier oil/gas mix is a fouled spark plug and slightly reduced performance.

The saw manufacturers will tell you that adding extra oil displaces the gas causing a lean run condition Now with that being said I have thought that even doubling the oil in the mix only results in a 2% change in gas/oil ratio. And if that 2% causing a lean failure you had problems before you even started.