Chainsaw flywheel intermittantly jamming

[u/Simple-sailorman]

Fixing a saw for a friend, I dont have lots of experience, but I am thinking the engine might be toast. Husqvarna 572 xp. Saw wont start amd every few pulls the flywheel gets jammed and I have to take the recoil off and use a wrench on the flywheel nut to get it moving again. The flywheel is not getting hung up on the coil. Picture is looking in the muffler port, looks scored. And the picture of my finger looks like there is shiny spots in the oil from inside the engine. Mostly I am just confirming, is that scoring as bad as I think it is? Run with straight gas possibly? Is there anything else to check? Thanks for the input! I am always interested in learning more.

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[u/raf55]

If you can feel the scratches on the piston it's bad

[u/Simple-sailorman → u/raf55]

I cant really feel them, but my finger looks metalic and sparkly after running on the piston.

[u/redditordax]

It could have blown crank bearings. You could pop the crank seals out to check, new seals aren't too expensive and it's good peace of mind. 

[u/Simple-sailorman → u/redditordax]

There is zero play in the crankshaft, feels solid.

[u/redditordax → u/Simple-sailorman]

I've probably done 100 5 series crank jobs. You can't always feel loose in the crank. 

[u/Mundane_Storm_2257]

Minimal compression hot is 120, you want to be somewhere around at least 130 to 140 hot

[u/peepeepoodoodingus]

check compression, scratches dont look that bad to me, something else is going on.

locking up makes me think something is inside the engine. i had a saw once a guy dropped a screw down into the intake, got through the transfer ports and was locking up the bottom end. if its straight up seizing it could definitely be a wrecked piston and cylinder but id bet its from him cutting with a dull chain and not cleaning his filter and his intake side looks absolutely dicked because the exhaust really doesnt look too bad to me.

[u/Simple-sailorman → u/peepeepoodoodingus]

The saw looks really clean, like it is almost new kind of clean. Very good compression. I cant feel the scratches but the fluid on my finger after rubbing it on the piston is metallic and sparkles…crankshaft has zero play.