Chainsaw with scored piston. How?

s219 · Jan 22, 2019

Buxus said:
2013 Stihl MS 362 with 18 inch bar; Cutting a holly stump about 16 inches, did not pinch. Saw died. Brought to dealer and was told it was scored piston. Initially dealer said it must be bad gas, which it isn't. Then he said must have overheated. $500 repair on a $725 saw. I'm pissed as ****, but don't know what to do.

I know this has been resolved for the OP, but I wanted to add a comment -- cutting a stump is one of those situations where you can overheat a saw very easily. Could be that the saw has another condition making it prone to overheat already, or the stump cutting causes it to overheat directly, but either way, cutting a stump increases the risk of overheating quite a bit.

When cutting a stump with the bar parallel/flat to the ground, airflow through the saw powerhead is greatly reduced. Combine that with the possibility of high RPMs due to awkward cutting and positioning, poor chip flow due to tight quarters (which may cause chips/dust to enter the cooling air intake more than usual), dull cutters due to grit in the bark or dirt, and it's the perfect recipe for overheating a saw. It can happen without realizing it.

I don't often cut stumps but I am real careful to baby the saw when doing so -- I'm more likely to plunge and pivot than to get the powerhead near the ground. I have heard way too many stories of someone killing or cooking a saw when flush cutting a stump, and it's just the perfect storm to cause problems. Can't say if that was the cause in this particular case, but as soon as I read the words "Cutting a holly stump about 16 inches, did not pinch" my eyebrows wrinkled up.

ArlyA · Jan 22, 2019

We cut stumps all the time. Most of the work we do is following a harvester and clean the stumps and debris they leave behind so as to make or clear, a trail. Most the the slash and debris is taken care of via pole saw but the stumps are cut as close to the ground as possible and practical with my MS 260 with its 20" bar. Yes, I should get a more powerful saw! These machines are made to operate on all angles. Of course if you fill the air intake with chips, all bets are off!

Jstpssng · Jan 22, 2019

Two coworkers have had problems with their 550 Husky's overheating after cutting balsam fir, which are very pitchy. After repairing them under warranty he dealer told them to prevent overheating again they should clean the fins occasionally with oven cleaner spray.

PILOON · Jan 23, 2019

Jstpssng said:
Two coworkers have had problems with their 550 Husky's overheating after cutting balsam fir, which are very pitchy. After repairing them under warranty he dealer told them to prevent overheating again they should clean the fins occasionally with oven cleaner spray.

Oven cleaner in spray form also is a great paint remover as well as a good carburetor cleaner.
Very caustic and will etch aluminum so good rinsing is needed to neutralize the effect. (I use hot water)