scored a scored 066

[motoOzarks]

Shouldn't have but I did.

Compression check put it right on the red/green line 3 times.

Starts and runs, carb is flooding cylinder

Was wondering what the thoughts on reusing this cylinder and maybe piston.

Can't feel anything with fingernail in cylinder, just visual

Can't feel with fingernail above rings, or barely can. can feel scoring below rings on skirt

I'm thinking cleaning up piston , hone cylinder with something like emery cloth, new rings.

What seez ya?

 

[popopboat]

Is plating gone?

If not a bit of scotchbrite and cylinder should be like new..
pistons are not that expensive to not replace

 

[Canadian farm boy]

Shouldn't have but I did.

Compression check put it right on the red/green line 3 times.

Starts and runs, carb is flooding cylinder

Was wondering what the thoughts on reusing this cylinder and maybe piston.

Can't feel anything with fingernail in cylinder, just visual

Can't feel with fingernail above rings, or barely can. can feel scoring below rings on skirt

I'm thinking cleaning up piston , hone cylinder with something like emery cloth, new rings.

What seez ya?

View attachment 286916 View attachment 286917

Cylinder should clean up easy. I don’t think I’d reuse that piston. Get a meteor piston. They’re about the best aftermarket piston available and they come with caber rings plus they’re considerably cheaper then a new oem piston.

 

[Maintenance Chief]

Id use that cylinder but scrap the piston, that piston doesn't look oem from that angle either? Can you confirm?

 

[Maintenance Chief]

Fyi red scotch bright pad is great for cleaning up the inside of the cylinder.

 

[Ketchup]

Make sure you figure out why it’s scored.

 

[Cooper264]

Yeah cylinder looks recoverable. Piston is a lost cause. Might take a sand pad to the edges of the ports real lightly to take off any burs

 

[motoOzarks]

Is plating gone?

If not a bit of scotchbrite and cylinder should be like new..
pistons are not that expensive to not replace

Great question. How to tell?

There is no visual or texture hint of cross hatch that I can tell.

 

[popopboat]

If you can make a deeper scratch its gone, otherwise not.

Remove transfers first with scotch, its really a safest way, cant damage plating and then check.

But from rough look, it should be good.

 

[motoOzarks]

Make sure you figure out why it’s scored.

Is there a likely cause in reference to where it happened on bore?

 

[popopboat]

Is there a likely cause in reference to where it happened on bore?

Air leak / carb issues (lean mixture)

 

[Ketchup]

Air leak / carb issues (lean mixture)

^probably that. Maybe dirt getting past the air filter. On 066 I suspect bearings and seals but intake side might indicate a leaky boot as well. All rubber is suspect on a saw that old (including carb diaphragms). You’ll need to pressure test once you get the jug back on. I would replace fuel and pulse lines as a matter of course.

 

[Nutball]

The damage is on the hottest part of the cylinder.

 

[Ketchup]

The damage is on the hottest part of the cylinder.

You’re right. Looks like PTO side of exhaust port. PTO crank seal would be my guess but you gotta pressure test.

 

[motoOzarks]

Id use that cylinder but scrap the piston, that piston doesn't look oem from that angle either? Can you confirm?

 

[motoOzarks]

The exhaust side bolts were not very tight, one was just snug. Can't remember which one. The gasket under where the damage is looks a bit different than the rest. Not much, but enough to make me wonder if it sucked air in.........