Stihl MS 180-C Scored Piston... Tsk Tsk

[Sam R]

Customer brought a 180-C in with the complaint that there was some issue with the multifunction lever. Seemed like an easy task - and it was, just had to re-seat the lever bar and adjust the tension on the short lever. Happened to notice that there was a kind of oily black runoff from the muffler though...

Took the arrester screen off and it was *caked* in carbon. The exhaust port was caked in carbon. Pulled the muffler off and the mounting flange was black! I couldn't really get a good picture of it but it had 2 distinct scoring lines viewed through the muffler port. Rings free - unit started and ran, for a few seconds - the spark plug as you might have guessed by now was totally carbon fouled.

Unit is not under warranty - I'll call and give the customer the option to trash it or rebuild it... I just really wonder what the heck he was running in it that caused this. The fuel out of it was.. let me think I believe a pale green, almost aquamarine color - I do not believe it was straight gassed. Maybe he somehow had the choke stuck on -- I'm open to suggestions. My thinking is the saw was lugged somehow; maybe the mixture being way off or just using really crummy 2 stroke oil.

It's just too bad, what a waste.

 

[HarleyT]

Was the air filter dirty? Exhaust screen missing? Dirt getting past the filter?
The saw is likely older than you think.

 

[HarleyT]

PICS!!!

 

[Sam R]

No I looked at the purchase date it was Feb of last year. Air filter wasn't too bad but there was some dirt on it. Like I said, the arrester was totally caked in carbon. Whoever bought it just didn't know what they were doing.

 

[Sam R]

I tried to get a few pictures but I couldn't, I'll try and snap a few tomorrow we have a little snake cam at the shop I could probably see that p&c real good with it.

 

[HarleyT]

OOOO, "snake cam"!!!

Sounds kinky!!

 

[Sam R]

It's kind of like the one that the doctor puts up your exhaust port but cleaner

 

[HarleyT]

It's kind of like the one that the doctor puts up your exhaust port but cleaner

Pics!!!!

 

[Mad Professor]

Running way too rich can result in carbon scoring of the piston. Did it look like this?

 

[brandonstc6]

I think pistons are pretty cheap for that model, but then there is the labor. Those clamshells are pretty easy if you have a cordless impact


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[Overkill338]

Ive got a Hyway slug and jug for a 180, new. PM if you want it

 

[Sam R]

Thanks for all the replies - Overkill I work in a dealership don't think they'd like me buying aftermarket parts for someone's saw.

And Prof, I looked through Stihl's engine failure analysis book for something relate-able - but the engine hasn't actually seized yet... It appears to have the 4 point scoring, which can I think as you said result from high carbonization. Now why it's so carbonized is something I intend to work out with the owner.

 

[grizz55chev]

Thanks for all the replies - Overkill I work in a dealership don't think they'd like me buying aftermarket parts for someone's saw.

And Prof, I looked through Stihl's engine failure analysis book for something relate-able - but the engine hasn't actually seized yet... It appears to have the 4 point scoring, which can I think as you said result from high carbonization. Now why it's so carbonized is something I intend to work out with the owner.

Maybe he ran something like seafoam through it.

 

[Sam R]

I'll keep you posted with what I find out when I call and ask/give the bad news.

 

[brandonstc6]

They cylinder is probably okay, and you just need a piston kit. I believe a oem piston kit is cheap. I’ve had some scratched pistons and the cylinder was fine. It doesn’t have to look new, just no scratches in the plating that can be felt with the fingernail.


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[Overkill338]

Thanks for all the replies - Overkill I work in a dealership don't think they'd like me buying aftermarket parts for someone's saw.

And Prof, I looked through Stihl's engine failure analysis book for something relate-able - but the engine hasn't actually seized yet... It appears to have the 4 point scoring, which can I think as you said result from high carbonization. Now why it's so carbonized is something I intend to work out with the owner.

My 360 had similar carbon scoring when I got it.

I missed the Stihlership part. The 180 is a disposable saw if aftermarket parts aren't used sadly.

 

[Deleted member 117362]

Maybe he ran something like seafoam through it.

+1, hate seeing people use that crap. More carb problems.

 

[Sam R]

I'll talk to the owner about it. Been pretty busy this AM getting orders in, I'll see what the customer pays for the cylinder. What I can see of it, the piston looks okay. And it starts and runs. Might be worth saving... Definitely a golden opportunity to share some knowledge with someone who doesn't know!
What's that old quote: "forgive them Father, for they know not how to properly care for and maintain a 2 stroke motor."

 

[1Alpha1]

It never fails to amaze me at what some can do to a chainsaw, or other pieces of O P E.

 

[cedar rat]

Took the arrester screen off and it was *caked* in carbon.

I bought a pair of MS 180's for carving, in no time one was running poorly and became hard to start. The shop took out the carboned up screen and I went home and removed the screen in the other saw as the Stihl shop told me it was a regular problem. Both the little saws have been good runners since the screens were removed.

I say if the rings are not showing damage, clean it up, throw another plug in it and make a few cuts and see if it clears out and runs good.