Stihl 066 Maintenance

[dgj32784]

Novice big saw user here. I recently acquired a Stihl 066 (trading in my MS311) and plan to mill some trees in my back yard. I also heat almost exclusively with wood and was looking for a larger powerhead to make quick work of bucking. I've run my 066 a few times now - not ripping - just bucking. I put a 20" bar on it with a full skip chain, which I think may have been a bit of overkill in terms of enhancing performance :biggrin: Since then, I've run it a few times with the 20" bar and after a few minutes of use the saw will cut off when idling. I'm pretty sure the idle is set appropriately, and I'm starting to wonder if the 20" bar and the full skip chain are putting some stress on the saw from the standpoint of "too much giddyup" - if there is such a thing. Does anyone have some basic rules of thumb for maintaining a high-performance powerhead like the 066? For instance, is there a minimum bar length for optimal conditions? I know the 066 can easily run 32" plus, but what about a "too small" number. Also, how long is too long to leave fuel in the saw when storing? How often (generally speaking) should you wait before replacing fuel filter, air filter, etc.? Recognizing this can be case dependent on operating frequency, duration, and conditions. Any words of wisdom are welcome. I'm not savvy on the general rules of thumb for maintaining a larger powerhead. My MS311 was not complicated at all from a maintenance and to- not-to-do’s standpoint.

Thanks,
David

 

[DanManofStihl]

When I had a 066 I ran a 20 and 24 inch bar most of the time and it loved it just don't over rev it out of the cut. Gas storage I use stabil it is good for a year air filter should be cleaned every tank or other tank of fuel changed that and the fuel filter once a year give of take of the condition.

 

[BobL]

. . . . Since then, I've run it a few times with the 20" bar and after a few minutes of use the saw will cut off when idling. I'm pretty sure the idle is set appropriately, and I'm starting to wonder if the 20" bar and the full skip chain are putting some stress on the saw from the standpoint of "too much giddyup" - if there is such a thing. Does anyone have some basic rules of thumb for maintaining a high-performance powerhead like the 066? For instance, is there a minimum bar length for optimal conditions? I know the 066 can easily run 32" plus, but what about a "too small" number.

There is no "too small" a number. However, it is probably better for the saw (and B&C) if the raker depth is dropped (or more specifically raker-cutter-wood angle increased) when regularly using shorter bars so that the saw works closer to it's max torque rather that running high rakers at close to WOT and just scratching the wood.

Also, how long is too long to leave fuel in the saw when storing?

This depends on;
- how fresh the gas was when you bought it
- how long you have had it for
- the airtightness of the container you stored it in
- what octane of fuel you started with
- how much old mix was in the saw when you last topped it up
- how much mix there is in the tank, - unless it's like 6 months old, less than 1/4 tank remaining I just top up with fresh mix and go for it
- and the square root of the length of your grandmothers nose
etc
On a hard working milling saw with more than half a tank in it I reckon 2-3 weeks and then toss it out. On my 50 cc Homelite garden pruner I keep using it even after 3-4 months in the tank

How often (generally speaking) should you wait before replacing fuel filter, air filter, etc.?

Light use - say every 2-3 yes for the fuel filter, heavy use every 6 months or so.
Air filter - just keep cleaning it until it starts to develop holes in it.

 

[gregfox]

For starters I would throw away the skip chain. That saw will handle full chisel on any bar up to 36". Next I would get out the screwdriver and adjust the idle screw(once its warmed up) so it stops dying. Then I would cut like its goin out of style

 

[gemniii]

<snip>Also, how long is too long to leave fuel in the saw when storing?<snip>

Any time, especially with ethanol laced fuel.
In Mississippi I get ethanol free fuel, throw in some stabil, and try to run the tank dry in the end.
I've had 4 engines "gum up" after leaving mix with ethanol in them for a couple of months. All were resurrected using Seafoam, but it took a while.

 

[mtngun]

after a few minutes of use the saw will cut off when idling.

I'd leak test the saw, check the fuel line and fuel filter, put a carb kit in.

 

[dgj32784]

Thanks to all who posted. Great information. After looking over the stihl carburetor manual and talking with another Stihl user, I think my issue is that the idle jet is "too rich." I plan to screw down the low speed screw slightly tonight and see if that does the trick.

If you don't hear from me on this topic again, it'll mean all is good.

Thx