Stihl Chainsaw Repair - Model MS362 - *UPDATED*

Late last year I was dropping and limbing a few trees, when I noticed that the chainsaw wasn't using any bar oil.  I stopped using the saw, and shortly afterwards heavy snow fell.  The trees I had felled were buried in snow all winter long - so there was no clean-up.

Now it's spring, and trees and limbs are cluttering the place up.  It's really a huge mess, and that's just five medium size trees - and the saw is not working right.

Go to the 1 minute mark to see what this saw will do.

Anyway, as I said, my saw is not working properly.  The chain isn't being oiled, because the oil reservoir doesn't draw down.  So I watched a couple of YouTube repair videos and then took it apart.

Below, what the chainsaw looks like when it's halfway apart.

 

Stuff I removed from the saw.  The broken bit is at the bottom right. 

The oil pump moves oil out of the reservoir and into the slot on the right, below.  The reason oil feeds into a slot rather than a hole is this:  The chainsaw bar must move back and forth, because as the chain wears, it stretches out.  The bar must be adjusted to maintain proper tension the on the chain, and so a slot allows oil to feed the bar across varying blade positions.

The bar has a small oil passage drilled at an angle that leads to from the oiler slot above, to the groove in the bar that the chain runs in.  This continuous oiling prevents friction from melting the bar as the chain goes round and round at high speed.  The bar has melted because there was a small piece of sawdust blocking the oil port - the small hole in the center.  The larger hole is for adjusting the tension on the chain by moving the blade.

When the oil port became blocked, oil was unable to flow, so of course the bar suffered damage.  However other damage occurred.  The pump kept trying to add more and more pressure, but the oil line was dead-headed.  Something had to give.  In this saw they install a sacrificial nylon gear that will wear down if the oil system gets backed up, and that is what happened.  The gear got chowdered.  Better a cheap plastic gear than an expensive oil pump.

So I have a new bar and oil pump bear on order.  In the future, I need to keep a close eye on that small oil port on the chainsaw blade, especially when swapping out chains in the field where things aren't so tidy.

Anyhow, the wife and I finally cleaned up all the branches and tree tops that I removed last fall.  It's going to make quite a bonfire.  This pile is over 8 ft high.

At least the yard is cleaner than it was.  I'll cut the trunks up and stack them out after I get the saw repaired.  We have some neighbors and members at our church who heat with wood, so none of the this will go to waste.

***UPDATE***
OK, so I got the parts that I knew were failed:

The bar:

And the nylon worm gear to drive the pump

 However the oil pump was bound up, so it still wouldn't pump oil.  I have a replacement on order from Amazon...

Yup I got it fixed, and bucked those four trees into 18" rounds in about an hour :)