MS260 tuning

I recently bought a used ms260 pro a few months back. Saw is in great shape but I can’t seem to tune the saw correctly in order for it to idle without the chain moving. I have tuned a couple stihl saws in the past so I have some experience tuning saws but I am no expert. I’ve read lots of stuff online but nothing seems to work. The other thing I’ve noticed with the 260 is it seems a bit underpowered? I know it’s only a 50 cc saw but I thought it would have more guts. I was used to using an 029 super. Any ideas guys?

 

Subscribed. I’m in the same boat can’t get the chain to stop


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2 likely causes if it is a well used saw. The first is obvious and it is the idle speed set too high after the low speed circuit has been tuned.
The not so obvious reason especially with a high miles saw would be a weak spring in the clutch. When the springs get weak the engine doesn't need to run as fast to engage the clutch. Other possible clutch issues would be a broken spring or an out of round clutch drum.
If you decide to go into the clutch, don't forget that clutches use a left hand thread.

 

Calling smart people huskihl and Armbru84 ..
Edit Oldman47 .Should have been added

 

I will let others with more experience comment on the tuning and chain rolling issue but as for getting a little more out of your saw I just opening up the muffler by adding 2 more holes same size as the original and then added the bar/chain/sprocket tuning kit to my MS260 Pro. The saw will need to be re-tuned after opening up the muffler but the muffler mod and tuning kit added some nice oomph.

 

I'm no expert, but the party line is: 1) Tune the L screw. 2) Set the LA 3) Set the H screw. I'm sure you have figured this out already. Next, consider replacing the air filter, fuel filter, fuel line and impulse line. Also clean the carb. Assuming all of this is in order, you should be able to tune the carb and idle speed. If not, you have problems in your clutch or piston/cylinder.

 

Most of the basics have been covered. There could be an air leak in one of many places, or the rings could be worn out, causing low compression.
If it sounds like it's idling low enough, but the chain is spinning, I'd also say the clutch springs or drum bearing are worn out

 

Thanks guys. I don’t think it’s a compression issue. Piston looks fine. I may have a shop look it over.

 

So, you had the muffler cover off? Just drill two more holes for the exhaust to get out. For some reason, they thought a single 10mm hole was good enough. You will pick up some power for sure and may even find it easier to tune. Clean all the goop out from under and around the drum. Clean & grease the bearing while you are right there...

 

Thanks for the suggestion. I may do that. No issues tuning after a muffler mod?

 

Anything I should know before drilling into the muffler? Just 2 holes on the outside?

 

Ok so I drilled 2 more holes in the muffler. One above and below the stock hole. Seems to run better. Is there any use in drilling holes on the sides?

 

If the two new holes are the same size as the original (+/- 3/8") you are good. That is what I did to my 260.

You will need to retune now that you have opened it up.

 

Does the saw bog or hesitate off idle?

 

Ok thanks. I did retune.

 

No

 

The L is tuned correctly then. You may be able to get a few less rpms by turning the L out a tad but probably not much until the saw would die.

Clutch springs, as mentioned will probably solve.

 

I think I’ve got it worked out now. Saw has good throttle response, slightly 4 strokes in the wood and the chain barely moves at idle. It may be the clutch spring/springs?? Like you guys have suggested. How hard are they to replace?

 

They are easy to replace.

 

Ok so I dig into the clutch housing and all these little pins fell out. What did I break? Lol