MS 251 problem.

[dannytreacy]

Hi all,

 

I've got the above chainsaw, it's about 8 months old and doesn't get hammered by any means.

 

It has been running fine but this week I noticed that when cutting at full throttle it would start to lose power and then stop running, though it didn't cut out.

 

I have tried adjusting the high rev control (there are three adjusters, 'h' 'l' and one for the idle setting, I forget the marking on that one ) but none of the adjustments seem to do much, I have referred to the handbook but it only covers the idle setting reall.

 

Does anyone with more experience have any knowledge of this type of problem?

 

Thanks!

 

Danny.

[detritus21]

Daft question but the filter is clean isn't it. That can have an effect and is often overlooked

[spudulike]

I take it the chain is sharp and the fuel mix is fresh - I would normally take the exhaust off and look at the piston for scoring and then strip and clean the carb - worth also checking the fuel tank breather is clear of dust.

[MATTMOSS]

Hi all,

 

I've got the above chainsaw, it's about 8 months old and doesn't get hammered by any means.

 

It has been running fine but this week I noticed that when cutting at full throttle it would start to lose power and then stop running, though it didn't cut out.

 

I have tried adjusting the high rev control (there are three adjusters, 'h' 'l' and one for the idle setting, I forget the marking on that one ) but none of the adjustments seem to do much, I have referred to the handbook but it only covers the idle setting reall.

 

Does anyone with more experience have any knowledge of this type of problem?

 

Thanks!

 

Danny.

 

If you have been 'adjusting' these screws without knowledge of what they do, I would recommend you take the saw to a professional and get them to look at it, before you do any further damage.

[dannytreacy]

Thanks for the replies, the saw has done about 10 hours cutting since new so I had hoped it didn't need stripping or servicing yet.

 

The chain is sharp and the mix very fresh, using stihl green oil, so I guess the other potential problem could be the fuel filter, the air filter is clean.

 

Cheers,

Danny.

[peatff]

Run the saw till it is hot or the adjustments are pointless. Try turning the h and l in till they bottom out lightly and open them out again one full turn and a quarter then tweak the screws when it is running again or take it in and get it looked at. Adjust the idle so the chain doesn't move on tick over with the brake off.