Ms261 alloy h limiter

[Rudolf73]

so in summary,

1-pop the cap with a drywall screw, (we call em tekscrews here in aust).

2- then unscrew the internal screw,the screw in the plastic piece is H screw and the plastic piece rouns it moves with the screw,

and with a bit of force from the 2mm ellen key the h screw will jump the raised bit and allow easy adjusting within the next say 340 degree of adjustment?

With a bit of force mine jumped on the spline connecting the plastic cap to the H screw. The raised bit should not jump the alloy but you will only find out once you try.

 

[koshari]

With a bit of force mine jumped on the spline connecting the plastic cap to the H screw. The raised bit should not jump the alloy but you will only find out once you try.

"so that being the case if you drilled out the hole in the cap to allow the 2mm ellen key to clear the cap it would adjust the screw without needing to remove the cap at all"?

forget that , the upper portion would still foul on the caps spline with the limiting cap in place.

 

[David (saltas)]

so in summary,

1-pop the cap with a drywall screw, (we call em tekscrews here in aust).

2- then unscrew the internal screw,the screw in the plastic piece is H screw and the plastic piece rouns it moves with the screw,

and with a bit of force from the 2mm ellen key the h screw will jump the raised bit and allow easy adjusting within the next say 340 degree of adjustment?

No the plastic will not jump the internal alloy rib.
The internal spline inside the white plastic will jump the metal spline on the high speed screw until it has screwed all the way out and is clear of the internal alloy rib.

 

[David (saltas)]

Always more than one way to skin a cat

I thought about just pulling the alloy cap and then giving the screw a half turn and then putting it back that would then not let me close the screw not a problem and the new full open position would be 1 1/4 turns out instead of 3/4 out.

I might have had to do this a couple of times to find the right amount of "bias" or "zero elevation". You would have to right it down or have a really good memory to know how much the screw was backed out.

This method will work

Brads ported MS261 saw is turned out 2 1/2 times I think.


Drilling out the center of the alloy so you can access the Allen key will also work, Eventually the White plastic part of the limiter would likely strip and not have the interference fit that it has now.
When you back this screw all the way out you can fell the plastic spline skipping over the metal spline of the High Speed screw.

This will work and you might even be able to freshen up the spline in the white piece of plastic if it becomes a problem by dropping it in a cup of boiling water " same way you can make a nyloc nut tight again".

I chose to do it the way I did
I did one mod once, I wont have to pull it apart again at a later date, after a muffler mod or porting etc.

I will be able to screw the screw in and count how far out it was, I don't have to write it down or remember anything. You might want to check this after doing a muff mod, and then re-tune the saw. The need to richen it up is evidence that it is breathing better and making more HP. e.g "after the muff mod I had to turn the H screw out a 1/4 turn"

I decided to post what I did after filling off the rib on the alloy screw plug and found out that more work was required. That is the reason there is no before picture of the rib on the alloy plug.

I read as much as I could and looked for pictures, poked and prodded the carby on the saw, scratched my head before doing it my way.

I will be very interested in how long the internal spline lasts on the white plastic on anyone who drills out the center of the alloy plug.
I think I might be surprised

The 2mm Allen key is 2.22mm from point to point so a 2.5mm, 3mm, 1/8th drill bit is all you need for clearance

May be a moderator will put this with the other limiter threads in the "chainsaw FAQ" sticky :msp_rolleyes:

 

[David (saltas)]

"so that being the case if you drilled out the hole in the cap to allow the 2mm ellen key to clear the cap it would adjust the screw without needing to remove the cap at all"?

forget that , the upper portion would still foul on the caps spline with the limiting cap in place.

Turning the Allen key to richen will turn the alloy plug and the white plastic part until the alloy plug rib will goes hard up against the internal rib this will hold the white plastic in a fixed position further turning the Allen key to richen will cause the spline on the metal High Speed Screw to jump the internal spline in the white plastic.

Turning the screw the other way will cause the whole assembly to rotate almost a full turn approx 340 deg until again he alloy plug rib will goes hard up against the internal rib this will hold the white plastic in a fixed position further turning to lean the mixture will cause the spline on the metal High Speed Screw to jump the internal spline in the white plastic.

 

[koshari]

well explained salta. originally i was a bit confused with the internal spline description because technically its a zigzag profile.

 

[SCHallenger]

Exactly right Rudy. Now if only I'd thought of that I'D look like the smart one

Mission accomplished & thanks again! You both look plenty smart to me. My 261 was first fired up on 5/30 & was used to remove 3 of the 7 trunks of a box elder (soft cousin to a maple) which had blown down. They ranged in size from 8in.-16in. dia. They were sitting in the front yard of a lady whose husband is wheelchair bound with MS. I offered to help, & she was very happy to accept. Good opportunity to break in a saw & do a good deed. When I made the first cut in an 8in. limb the saw seemed to labor. The chain was an RMC3 .325. It took only a few more passes when I decided that it was lean. It was already against the H limiter, so I richened up the L as much as possible & adjusted the idle speed upward to keep it going. This helped some, but I figured that the only right way to go was to do what so many have done. I didn,t want to free rev it at WOT until more work under load had been done, so I ran a couple of tanks through it then checked it with the tach. It was turning 13,900. Not bad but it still sounded & felt too lean. That brings me to where I started. As per your information provided, the alloy limiting casing was removed & the screw was opened (looked to me as though the white plastic tab jumped the internal rib). It now is turning 13,500 & sounds & FEELS much better. I,m on my way "up north" & will be putting it to work in 24hrs. or so. Many thanks again!

 

[Kingsley]

So I cut the white tabs off the limiter screw and I'm good right. I have done this before to other Stihls, but with all this talk about drilling and filing I'm thinking has something changed?

Is anyone removing the limiters from the L?

I really haven't played with the carb adjustment on mine at all. It runs great the way it is. I'll look into it though, because I'm nervous about the high reving engine reving to high. It really sounds like it is up there in the revs when operating. It also backs down off of high rpm like a dirt bike.

Thank you for all the info!

M

 

[young]

Is anyone removing the limiters from the L?
M

there isnt one on the low screw.

 

[David (saltas)]

So I cut the white tabs off the limiter screw and I'm good right. I have done this before to other Stihls, but with all this talk about drilling and filing I'm thinking has something changed?

This thread was started because the limiter on the MS261 is different from older stihls.

If you can adjust the H in and out without something stopping then you have what you need.

All the extra talk was about the many ways you can achieve the same result on a MS261

 

[Bowtie]

That alloy limiter sure as hell dont come out as easy as the older style red plastic...

 

[deye223]

opcorn:

 

[David (saltas)]

2mm Allen key is the way to go and just turn it a bit so that it is in the zone

removing the rib is only needed if you get lost and want to be able to screw it all the way closed and back out to the recommended starting position

 

[nmurph]

So, this needle has a cap over the needle and a limter on the needle also? Remove the cap and use a 2mm allen to "strip" the limiter on the needle? I'm getting one of these in the next couple of days.

 

[deye223]

2mm Allen key is the way to go and just turn it a bit so that it is in the zone

removing the rib is only needed if you get lost and want to be able to screw it all the way closed and back out to the recommended starting position

yep i red that in matts post so i got one and tryed it and it turns so i will re tune tomowow fingers x

 

[David (saltas)]

So, this needle has a cap over the needle and a limter on the needle also? Remove the cap and use a 2mm allen to "strip" the limiter on the needle? I'm getting one of these in the next couple of days.

If you use the Allen key with out defeating the limiter the needle will jump the spline but it will not completely strip it unless you do it a lot of times.

If you wan an extra 1/4 of a turn out of adjustment then turn the limiter out so it is on the stop and then use the allen key you will feel it jump the spline a couple of times until the key has turned the extra 1/4.

When you turn the h limiter the other way it will not be fully closed but a 1/4 turn from it.

I removed the rib and the little plastic tabs and can turn mine were ever I like and if I get lost I can screw it closed and back out 1 and 1/4 turns to the recommended starting point.

My spark screen is out and mine is about 1 and 1/2 turns out and 13800 rpm.

I had it a tad richer 13400 rpm for the first 5 litres of fuel.

In hindsight I would

a) turn the limiter rich
b) insert 2mm allen key
c) give it an extra 1/2 turn so it is in the ball park
d) back it of the 1/2 turn
e) tune it

I think the H limiter is less likely to move away from the setting (wandering due to vibration) with all of the limiter stuff intact

 

[dbittle]

Great Information

I much appreciate the limiter cap info. I borrowed a nearly unused 261 from a friend at work to work on some larger trees in my yard. I shut it down on the first cut because it was screaming lean and used my ancient 025 to finish up the tree I was removing. The info in this thread was just what I needed. I pulled out the metal limiter cap and dialed in about 3/4 turn extra. I will put it in wood and fine tune it next chance I get. I looked at the piston and nothing is scored, so that's good at least. Best of all, my buddy's saw will live longer and his warranty is intact.

 

[belgian]

My neighbour brought in a MS261-C from 2010 which gave up on him. It turns out that the piston was scored badly and his dealer claimed that he overheated the saw while running it for to long. Now my neighbour is 77 years old and only cuts firewood for personal use, so I found that argument a little poor from the dealer side.
My take on it is that this saw was running too lean. I decided to rebuilt it for him but will make sure to fatten the H screw a bit. Reading this thread, I still can't really understand how to remove the limiters on this carb ; a pity also is that the pics have been removed in this thread.
Can anyone explain how to pull the alloy screw of this carb ? any help is appreciated

Here's a pic of the carb and piston

 

[redfin]

There is a pin protruding down from the barrel around the cap. I can't recall if its all the way turned left or right.

There is slight force required to overcome the lip on the cap but it will slide out when the pin is aligned with the groove.

 

[Termite]

Oh no Belgain, a saw running 14,600 RPM's and a lean condition. I can't believe the professional Stihl dealers would let this happen!!
This reminds me of the handgrenading Dolmar 5100's we had a few years back.