372 scoring on both sides

[husqvarnaxpman]

What causes scoring on both sides? Low hour 372 40:1 mixture

 

[beaglebriar]

I’d say bad/old gas. That’s pretty minor scoring.

 

[husqvarnaxpman]

Still read 140psi Was wondering if gas would do that on both sides

 

[Canadian farm boy]

Cold seize or possibly an A piston in a B jug?

 

[husqvarnaxpman]

Cold seize or possibly an A piston in a B jug?

I will take a look. Thanks guys for replying

 

[beaglebriar]

How did the base gasket look when you pulled the jug? I’ve found more than one of these with a wrinkled gasket that causes a minor leak.

 

[Maintenance Chief]

Pin hole in the fuel line did that to a ProMac 800 i have.

 

[drf256]

Very odd. Was any machine work done to jug?

Looks like cold seize, as they are diametrically opposed to each other.

The usual spot for lean seize is the PTO exhaust side of the skirt.

 

[husqvarnaxpman]

Thanks guys for helping. Piston was ab in a b jug. No machine work but base gasket delete with hondabond. Im not going to use anymore of the gas mix but the other two 372's and 346 look perfect. Fuel line was brand new but don't mean it isn't defective. Maybe cold seize but I always let them warm up 1-2 minutes before cutting. Maybe not enough? It did die during a cut. Saw is 100 percent oem and was built about 4-5 tanks ago with brand new crankcase with factory installed crank, bearing and seals. New jug and piston, new carburetor and new fuel tank. Was wondering if there was any chance the carburetor or tank vent could do this? The tank vent is set up like a xtorq would be. The tank had pressure when i went to drain the gas out of it and then when i pulled the fuel line from the carb i heard a bubbling sound similar to a kid making bubbles in his drink with a straw. I had never had one do that before. Thanks again fellas.

 

[huskihl]

That’s a cold seize. It’s from cutting with a cold saw. Too much heat too quickly in the piston and the skirts grow before the heat can get transferred into the cylinder