Studid is as stupid does - Part Deux

[Anton Habsburg]

Well, I have managed to avoid cutting off body parts, but I think I have made the second most common mistake of operating a chainsaw. I ran my poor abused Husky 55 Rancher too lean, over rev'ed it and seized the engine.
So now what?
Do I have to completely rebuild the engine?
I have managed to disassembley the engine without losing any pieces or breaking any parts further.
The cylinder is visably scored, but I can't feel anything when I run my finger over it. The piston is also scored, a little worse than the cylinder, but nothing that a little steelwool could smooth out.
I really don't want to put $200 into new cylinder considering I only paid $360 for the saw two years ago. Especially since I could buy an entirely new Poulan for less than $150.(If the saw is only half as good, but a third the price, is it a bargin?)
Your thoughts are appreciated.

 

[eyolf]

Hard-chromed and Nikasyl cylinders are pretty tough, and sometimes survive a catastrophe. Do you have any aluminum transferred to the cylinder? I've heard that sometimes mechanics cook it out with judicious use of strong acid, but also that the process is tricky.

If your cylinder is OK, you could try to get by with just rings, but I'd also spend about $75 (guess) for a new piston. probably get several years use out of it.

 

[Anton Habsburg]

Well, that's about what I thought. I have a ring and gasket set on order.

The next question is, why did this happen? And how do I keep from doing it again?

The saw was running poorly...it would bog down when under load, but would rev fine when free wheeling. It idled ok. I thought it was because I was running summer gas during the winter, so I got some fresh gas...no change. The filter might be getting near the end of its useful life, but I figured that would make it run rich, not lean.

 

[John in MA]

Sounds like your high-speed mixture screw was set too lean. You want to to "four-cycle" or burble when it's wide open out of the cut.

 

[Fish]

You need to find out what burnt the saw up in the
first place, or it will just happen again. Any air leak,
carb problem, fuel or impulse line leak can do it.
Carb is the most likely, but Electrolux saws have
a problem on some of their saws with an impulse
hose developing a hole. While you have it tore down
check all of these things.

 

[Anton Habsburg]

What's an impulse line?

 

[Greg Carberry]

An impulse line is a line that transfers crackcase vacume to things such as the carb so it can pump fuel or on cheaper saws the oiler. Most I've seen are internal though right to the carb through its mounting point. You'll know you have an impulse line if you have 2 rubber lines going to the carb. The other will be for the gas.