Troublesome Ms261

[lewisyounger16]

You can get spring loaded ( three legged ) hones that you can put in a drill . This ensures , pretty much , that it stays round .

I was put off by those when researching as you could allegedly damage a transfer or something if a stone snags them.

[adw]

Flex hone to remove alloy off cylinder wall, not the spring stone type, they do not work well in two stroke cylinders.

[spudulike]

Right - 120PSI is well below the 150+ I would expect. Check the gauge out on a working saw and see what it pulls. Hones - Damn, been doing it wrong for years, I need to recall hundreds of machines.....bollocks!!! The stones are better in closed transfer cylinders but do the job in my limited experience

I have recently had a failure in a similar way, my diagnosis was that the bottom ring had seized and the top ring had stayed loose and continuing to run the saw had put a very slight cavity up the bore where the stuck ring had taken microns off the bore in one specific area. My fix was a new P&C kit and it worked.

I could see from the new piston that the rings were not worn in one small area, inspection of this area showed the hone had missed this part of the bore due to this vertical channel of wear.

 

[The Technician]

Did you check or change the fuel filter in the tank? The Stihl fuel filter is designed that if 2 drops of water hit it, the fiber swells and stops the flow of fuel. Take the fuel filter out of the tank and blow into it. It should be easy to blow in it. I recommend that you put a new fuel filter in. The part number is 0000 350 3500 or you can also use 0000 350 3518. If this unit is the m-tronic, did you remove the servo and check for dirt in it??

[lewisyounger16]

Did you check or change the fuel filter in the tank? The Stihl fuel filter is designed that if 2 drops of water hit it, the fiber swells and stops the flow of fuel. Take the fuel filter out of the tank and blow into it. It should be easy to blow in it. I recommend that you put a new fuel filter in. The part number is 0000 350 3500 or you can also use 0000 350 3518. If this unit is the m-tronic, did you remove the servo and check for dirt in it??

New filter. Always a new filter. Good to know about the swelling though.

[spudulike]

Just put a genuine Stihl fuel filter on a pipe, dunked it in a glass of water and sucked, can't say it tasted great but it let more than a drop or two through.....well, a half glass before I had to stop!

I really don't like these "internet facts" that aren't based on fact and go against the water and water damage I have found in carbs.

Don't believe me - go try it yourself!

[Ratman]

Just put a genuine Stihl fuel filter on a pipe, dunked it in a glass of water and sucked, can't say it tasted great but it let more than a drop or two through.....well, a half glass before I had to stop!
I really don't like these "internet facts" that aren't based on fact and go against the water and water damage I have found in carbs.
Don't believe me - go try it yourself!

Uhoh.... here comes another!..........










here it is! [emoji51]

[wyk]

On 11/12/2018 at 19:04, Stubby said:

That sounds like an air leak . crank seals ? 120psi is on bottom limit don't you think ?

It's the bottom limit for sumfin like a 125cc McCulloch. In a 261 what that should do is pop, start, run a bit, then once warm have running and idle issues until it dies and you spend way too much time trying to restart it, and then some crazy dude comes along and starts to drink water through it's filter to prove a point.

[spudulike]

Crazy dude......you smooth talker! I just like to test the theory of statements I don't believe and in this case, it was a load of bowlocks - should have used a glass full of something alcoholic I wasn't proving a point, more proving that what I thought sounded a bit iffy was in fact very IFFY!

120 is well low and even when damn hot it should pull late 130s or early 140s! Cold it should be 150-170 IMO!

The issue is either with the saw or the method of measurement - just need to find out which and move on!

[lewisyounger16]

Crazy dude......you smooth talker! I just like to test the theory of statements I don't believe and in this case, it was a load of bowlocks - should have used a glass full of something alcoholic[emoji33] I wasn't proving a point, more proving that what I thought sounded a bit iffy was in fact very IFFY!
120 is well low and even when damn hot it should pull late 130s or early 140s! Cold it should be 150-170 IMO!
The issue is either with the saw or the method of measurement - just need to find out which and move on!

It's running now, turns out the carb was pretty much blocked with something as the little strainer mesh was missing. Replaced it and then ran the saw up and richened the h screw until it sorted itself out. Need to get it running until its hot now. I'll check another saw, I'm using a gunsons gauge with the valve on the tip, pull it over until it stops moving the needle.