Husqvarna 61 scored cylinder

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jdvsn83

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Hey guys, today a costumer came to my workshop with a brand new Husqvarna 61 (they still make them here in South America). It had not compression.

I have never seen a cylinder scored like this one is. No aluminum transfer, piston in good shape if compared to its cylinder, and only 2 hours of use. Nothing like everydays no oil or lean seizures. However, the saw won't be repaired under warranty because it was bought 2 years ago.

I would like to know your opinions. What could cause this?

Thank you in advance for your time and sorry for my bad english.

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Well.....in my opinion that saw has more than 2 hours run time on it just judging from the dirt build up on the flywheel and other areas and the amount of carbon on the piston crown. My guess would be very bad oil over a longer period than described to you. Looks like carbon scoring to me......I assume the ring is stuck in the lands giving you a poor compression reading?
 
Your english is better than my spanish, so no worries there haha. My best guess would be debris in the crankcase? That seems like a lot a of carbon on that piston, how much run time does this thing have?
Edit: missed where it said 2 hrs run time. No way in the world....
 
Well.....in my opinion that saw has more than 2 hours run time on it just judging from the dirt build up on the flywheel and other areas and the amount of carbon on the piston crown. My guess would be very bad oil over a longer period than described to you. Looks like carbon scoring to me......I assume the ring is stuck in the lands giving you a poor compression reading?

Interesting opinion.

The ring was totally free. I think poor compression is due to those scoring marks. It's not visible in pictures, but they're reaaly deep.

Thank you!
 
Your english is better than my spanish, so no worries there haha. My best guess would be debris in the crankcase? That seems like a lot a of carbon on that piston, how much run time does this thing have?
Edit: missed where it said 2 hrs run time. No way in the world....

So 2 of 2 say there's no way this saw have 2 hours run time or something similar.

There's a very thin coat of something similar to carbon mixed with oil in crankcase walls...

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I went up in magnification and they do look deep.....and as you say no aluminum transfer.....what is harder than chrome? Carbon or sand...how do the bearings feel? If it isn't carbon or other foreign debris then perhaps a bearing failure but that generally shows up in the combustion chamber as well and that one doesn't show any abuse at all up there.......that brings us back to poor oil or poor fuel mixing....resulting in large carbon deposits. My best guess......
 
I went up in magnification and they do look deep.....and as you say no aluminum transfer.....what is harder than chrome? Carbon or sand...how do the bearings feel? If it isn't carbon or other foreign debris then perhaps a bearing failure but that generally shows up in the combustion chamber as well and that one doesn't show any abuse at all up there.......that brings us back to poor oil or poor fuel mixing....resulting in large carbon deposits. My best guess......

Bearings look like new.

Bad quality oil is very common here in Argentina. Maybe 1/10 customers use JASO FC or FD oils...
 
But how do the bearings feel when turning the crankshaft over 3-4 revolutions? Any tight spots or hitching or do they move very smoothly as you would want them to?

Are two stroke oils available there or do some folks use automobile oil?

They move as smoothly as new.

2 stroke oils are available. I sell and use Husqvarna XP and Echo Power Blend, but most people use scooter 2 stroke oils or old chainsaw TOTAL JASO FB oils.

I can't convince them to use expensive oils and here we have the results... Some tools like his Echo CS-510, Stihl MS170 or Husqvarna 143R didn't show problems, but this Husqvarna 61 now needs new piston and cylinder.
 
Used motor oil will leave residue like that... seen it with a local old-timer that didn't believe in these fancy "new" oils.

This was used with bad quality 2 stroke oil for scooters. Maybe there are some impurities in it.
 
Thank you very much for your opinions. They're always helpfull to learn new things!
 
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