Stihl 362 loose spark plug results

Da Coach

Da Coach

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The spark plug was combining loose On my Stihl 362 and I’m afraid I waited too long to repair the threads. The piston and cylinder have been scored on the exhaust side. i Would think its at least new rings. Can the piston and cylinder be saveed. I have a repair kit for the spark plug problem.

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mexicanyella

mexicanyella

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I think that’s just a little wad of paper towel in front of the skirt, not a chunk out of the skirt, right?

Has anyone ever taken some fine emery cloth or some such to a piston like that to smooth the scoring, cleaned them ring grooves, replaced the ring and continued running it? I’ve heard of such things on certain two-stroke dirt bikes with expensive or hard-to-get pistons (I’m thinking of a guy I knew who rode a 1970s KTM MX bike...)
 
trains

trains

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I think that’s just a little wad of paper towel in front of the skirt, not a chunk out of the skirt, right?

Has anyone ever taken some fine emery cloth or some such to a piston like that to smooth the scoring, cleaned them ring grooves, replaced the ring and continued running it? I’ve heard of such things on certain two-stroke dirt bikes with expensive or hard-to-get pistons (I’m thinking of a guy I knew who rode a 1970s KTM MX bike...)

Dont use emery cloth, use a file, and gently take the high spots off.
using emery will embed grit, or runs the risk of adding grit into the piston surface, and that will abrade the cylinder wall which is not good.
Running a file across the top high spots, and moving the file so as to not just swipe across one spot, but (engineers corner filing) should give a good result.
ie when passing the file over the piston, the tip or end of the file should start close to the piston surface, but as the file is wiped across the surface, the tip is moved up and away from the surface, thus you dont get a flat part worn into the piston.

you get the idea.
 
mexicanyella

mexicanyella

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Dont use emery cloth, use a file, and gently take the high spots off.
using emery will embed grit, or runs the risk of adding grit into the piston surface, and that will abrade the cylinder wall which is not good.
Running a file across the top high spots, and moving the file so as to not just swipe across one spot, but (engineers corner filing) should give a good result.
ie when passing the file over the piston, the tip or end of the file should start close to the piston surface, but as the file is wiped across the surface, the tip is moved up and away from the surface, thus you dont get a flat part worn into the piston.

you get the idea.

I can visualize that. Thanks for the info!
 
jp233

jp233

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if you can hook a fingernail on cylinder gouges or if port damage is too much to blend out, then it needs a re-plate or replace. Re-plating is not worth it on these saws since there are replacements available, and it's much more quick, set specs - etc. Re-plating is usually more for high-performance modified cylinders (or to bore out for custom piston applications), or cylinders made of unobtanium (cannot get anymore).

I'd say yea - replace P&C and make sure there isn't other issues with the bottom end (bearings and seals, et al)
 
Da Coach

Da Coach

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if you can hook a fingernail on cylinder gouges or if port damage is too much to blend out, then it needs a re-plate or replace. Re-plating is not worth it on these saws since there are replacements available, and it's much more quick, set specs - etc. Re-plating is usually more for high-performance modified cylinders (or to bore out for custom piston applications), or cylinders made of unobtanium (cannot get anymore).

I'd say yea - replace P&C and make sure there isn't other issues with the bottom end (bearings and seals, et al)
Thanks always appreciate the knowledge base on this form.
 
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