MS660 tuning for milling

[danieltree]

Please stop and bring it to a saw shop. You said that this saw was fairly new so if i were you I would pay the guy at the saw shop to do it . It will be cheaper than burning up your saw.​

 

[mtngun]

OK so what is squish?

How close the piston comes to touching the top of the cylinder, around the perimeter of the piston. Assuming you have a newer saw with decent compression, you don't need to worry about squish. But if you ever rebuild your saw, it is a good idea to check the squish. Hot rodders often use a thinner gasket to reduce the squish and boost compression.

Does it matter where I drill the extra holes in the inner cage of the muffler. I have not taken the muffler off yet, but it appears as if the inner cage can not be removed from the muffler itself.

Right, the cage is spot welded to the muffler. I don't think it matters where the extra holes in the cage go, use your own judgement.

How long can I go without mounting the auxilary oiler.

There is no right or wrong answer but I think an aux oiler is a good idea.

Any suggestions on where to get the bar and what kind?

Baileys works for me.

Someone asked about how to enlarge the exit hole on the standard 660 muffler. I used a carbide burr in a drill, a dremel or die grinder would have been more appropriate.

Someone said you need to let the dealer tune it for you. Tuning is very important on chainsaws because they are basically cooled by the fuel mixture. If the saw is not tuned right, it overheats and you end up with a big repair bill.

On the other hand, every saw I've ever got my hands on needed carb tuning, including a saw that had just received a dealer tune-up. If you are going to mill with a saw, you really, really need to learn to tune the carb.

Lots and lots of questions flying on this thread and I can't keep track of them all.

 

[BobL]

I run my aux oilers on all my bars (16 to 16") but these are used to cut Aussie hardwoods. Others can give you advice about your local softwoods .

:jawdrop:bobl is that a typo,hope ur not starting to slip,LOL LOL

Yep - I fixed it, 16 - 60"

Thanks

 

[JELIII]

I will probably end up taking to a shop after I modify the muffler. I need to find a good saw shop, because the local hardware store where I bought it doesn't seem too on the ball.

I guess it isn't necessary to remove the cowling over the exhaust hole to enlarge it?

I have read a number of other threads and posts here that recommend enlarging the existing hole, but this will be a real bi#%@ working under that small cowling on the stock muffler. Any suggestions? I am considering cutting it off and welding it back on after I enlarge the hole. There are two holes in the muffler, the round one and then a small slot in front of it. I plan to leave the slot as is and just enlarge the hole to 3/4.

Is there a trick to removing the limiters?

Thanks again for all the help.

 

[mtngun]

I will probably end up taking to a shop after I modify the muffler. I need to find a good saw shop, because the local hardware store where I bought it doesn't seem too on the ball.

Most of the saw shops in my area are primarily ATV dealers and saws are a small part of their business. They might have one mechanic who knows saws and the other mechanics are ATV guys. I do not assume that the dealer knows how to tune a saw correctly.

I guess it isn't necessary to remove the cowling over the exhaust hole to enlarge it?

The cowling makes it awkward, but you can work around it with the right tools.

Is there a trick to removing the limiters?

I think Stihl actually sells a special tool to remove limiters, dunno the part number. I screw a drywall screw into the limit cap and then yank it off, but the limit cap is usually destroyed in the process. You don't have to reinstall a limit cap, but the caps provide a better grip for your adjustment screwdriver compared to a bare screw (but trim the stops off the caps before installing them).

 

[danieltree]

I pass 3 Stihl dealers that service saws to get to the guy i use. JELIII said his saw is fairly new so that implies warranty to me. It would almost be better to run the saw with its factory settings than to adjust the carb wrong. If you get in the phone book and find the loggers or tree services in your area and ask them who they use you might find a great saw mech.​

 

[excess650]

Where are you in central Pa?

As for the muffler, if you are going to modify the existing outlet, pull the front cover, pull the screen from the outlet, enlarge the outlet from the inside, clean the filings out, reinstall the screen, and then the front cover. Drilling or removing the inner cage really isn't necessary.

The DP muffler is kinda loud, but I wear muffs or plugs anyway. Letting the hot exhaust out isn't a bad idea...

As for tuning, the limiter caps will come off, and its not a bad idea to put them back on. I prefer to have my milling 066 4 stroke at 11-11.5K. If you have a tach, tune the H fully CC to the limter and check for max rpm. If its still too fast, you'll need to pull the limiter cap to make the mixture richer. The extra fuel will help to keep the saw cooler on the long cuts experienced while milling.


I've pulled the muffler and had a peek at the piston and cylinder after milling in hot weather, and the engine shows no signs of problems. I did trash a clutch spider, but something has to give.

Again, use fresh pump premium and good mix oil 40-1. I've used Echo Powerblend since it was available in gallons locally for less than $25, and it has worked well without excessive carbon, smoke, or nasty smell. The synthetic blends seem to be really good without the higher price of the full synthetics.

Let your saw idle for 30-60 seconds after a long cut so that it might dissipate some heat. Refueling, refilling the oil, and sharpening the chain are all time for the engine to further cool.

 

[JELIII]

I am just north of Harrisburg outside of Dauphin.

I pulled the caps and removed the tabs and got them back in without a problem. I also enlarged the muffler hole to about double what it was. I am not sure how you could do it from the inside because the cage seems to be in the way. I did the best I could from the outside with a file and die grinder. I also put three new 1/4" holes in the end of the inner cage.

Any thing special I need to do to the gasket between the muffler and the head before I reinstall it?

I don't have a tach so I was going to start with the high about a 1/4 turn out past the limiter and see if I could tune it by ear. If a tach is absolutely critical I will certainly spend the $80 before I cook my saw.

Thanks for the help.

 

[mtngun]

Any thing special I need to do to the gasket between the muffler and the head before I reinstall it?

No, nothing special, just make sure it stays in place while you get the two bolts started.

Sounds like you did everything right.