seized concrete saws

[Cord]

I've been given three concrete saws, two Stihl TS450's and one Partner 970. The two Stihls are apart, it would appear the piston rings broke. One put a piece of ring above the piston and it hammered the piston top pretty good. Other one looks like the top ring land broke. The piston skirts and cylinders look great. Both crank cases are dirty and would need to be cleaned. It's not obvious to me why the rings would have broken. Tanks are partially filled with oil mix and it smells fresh. The Partner saw is together and is tight. I don't know if all three saws failed at the same time or if they were accumulated over time. I'm thinking about throwing a piston, jug, carb and intake boot at all three saws and see what happens. That'll be about $200 in parts for each saw. The Stihls are worth around $5-600. I'm on the fence if the profit is worth the trouble. I'm interested in keeping the Partner because it's a 16". If I sold the other two saws, I could get a great concrete saw for $0. My major hold back is trying to figure out why the saws failed in the first place. I know that just replacing parts does not necessarily address the reason for the failure.

 

[Roadworthy]

It could be something as simple as the wrong oil mix proportion or using regular engine oil instead of two stroke oil. Many modern two stroke engines use a 50:1 mix ratio but not all oils will lubricate adequately when diluted that far. It's also possible these engines were not intended to run at that ratio.

 

[ruffdog]

Run hard using a lower octane fuel?

 

[dfkrug]

I have had one Target and 3 Husky 2-stroke circular saws. All needed rebuilds.

What kills many of these saws is: employee or renter abuse, overheating them in hot weather, and getting water or concrete dust inside them. That is on top of the usual 2-stroke killer: improper premix fuel. Dual air filtration helps with the dust. That's just my opinion.

I also found that selling used concrete or steel-cutting saws is hard unless they are super-cheap. 2 of my Huskies shared most parts with the 372XP chainsaw, so I converted them. Partner became part of Husky, so now the Husky cutoff saws are essentially Partners.

 

[Egon]

Concrete dust.

 

[Stimw]

Parts for Stihl saws are STUPID expensive!
Worked on some concrete saws awhile back.
My theory is they drop or throw them and that breaks carbon loose in the muffler and it falls into the cylinder.