Limiter Cap Access?

[KindlingKing]

Newbie question here.

How do I get to the limiter caps on my MS 660? My carburetor is surrounded by plastic. Where do I start? I took my air filter off and the black plastic plate it attaches to appears to be held firmly to the orange cowl. There are four screws below the air filter but they won't back out with the black plastic plate in place. Aggg. I just got the saw, so don't want to go prying and snapping plastic tabs that can't be fixed. My dilemma, stock with the high speed screw all the way out the saw is turning 13500 rpms (I'm at sea level). From everything folks have written, this seems unreasonably high, especially from the factory and no way to lean it up. I really want to put my dual port muffler on but don't dare until I've dealt properly with the limiter tabs. Crying for help........ Lakeside, Thall, others???

 

[Trigger-Time]

Newbie question here.

How do I get to the limiter caps on my MS 660? My carburetor is surrounded by plastic. Where do I start? I took my air filter off and the black plastic plate it attaches to appears to be held firmly to the orange cowl. There are four screws below the air filter but they won't back out with the black plastic plate in place. Aggg. I just got the saw, so don't want to go prying and snapping plastic tabs that can't be fixed. My dilemma, stock with the high speed screw all the way out the saw is turning 13500 rpms (I'm at sea level). From everything folks have written, this seems unreasonably high, especially from the factory and no way to lean it up. I really want to put my dual port muffler on but don't dare until I've dealt properly with the limiter tabs. Crying for help........ Lakeside, Thall, others???

The way I done mine........I bought the cap remover and new caps
from a Stihl dealer, Then removed rubber boot on the side where you
adjust the carb, it prys out......helps if the boot is warm. Used the tool
to remove the caps, cut the tabs off the new caps and installed.
Tool and new caps cost less than $10 I think it was more like $7
The saw is worth the money and with new caps its worth the piece
of mind, that they wont move while using the saw IMO

I will get the part numbers in a min or two for you.

Cap puller...5910 890 4500
caps..........4203 121 2700

 

[Trigger-Time]

KindlingKing, You can do a search, Lake posted a pic of the cap puller
not very long ago........Their is a lot of info on this.......AS, is where
I found the info................

 

[KindlingKing]

Triggertime,

A big thanks! Wasn't sure about that rubber boot and didn't want to mess it up. I will get the puller. Thanks for the part numbers for the puller and the caps. Definitely want to get the new caps. I read that its worth it. Again, thanks.

 

[Trigger-Time]

Triggertime,

A big thanks! Wasn't sure about that rubber boot and didn't want to mess it up. I will get the puller. Thanks for the part numbers for the puller and the caps. Definitely want to get the new caps. I read that its worth it. Again, thanks.

You will any way........but go slow and easy pulling the boot..the boot
is tough but you don't want to scratch the saw, also the non-dp muffler
will have a gasket, you won't need it with the DP cover......less pressure
in the muffler with the DP You must have a tach if you know it's
at 13,500 rpm, need to have the air filter clean and chain adjusted properly
and tank is full or close to it before checking the rpms. You will like
the DP

 

[Lakeside53]

and 13,500 is acceptable... I run mine a tad lower, but... If your gas has 10% alcohol, it will rasie your RPM 500-800+... so try to run premium non-alcohol gas if you can get it. All the factory saws are shipped with the H limiter in the full CCW position - to stop you from introducing more unburnt hydrocarbons by making it richer.. oh well.. thanks EPA..

 

[Ray Bennett]

My local stihl tech advised me that there is no reason to put on new caps if you are removing the tabs and that the carb screws should not move. For years I have run my saws without the caps and nothing has ever moved. Heck, for years saws did not even come with caps. I would be interested in hearing what Lake and some of the other experts think about leaving the caps off.

 

[Haywire Haywood]

Well, I'm no expert, but I just ordered new limiter caps for my 346 because the tiny screw head that is left after you remove the caps is a pain to keep a screwdriver on when the saw is running.

Ian

 

[Sethro]

My local stihl tech advised me that there is no reason to put on new caps if you are removing the tabs and that the carb screws should not move. For years I have run my saws without the caps and nothing has ever moved. Heck, for years saws did not even come with caps. I would be interested in hearing what Lake and some of the other experts think about leaving the caps off.

I'll second that!

 

[Trigger-Time]

I'm going to stick with the new caps............If you dig a little
deeper into this you will find out that the new saws, with the
caps no long have the springs on the screws to keep them
from turning..........but it's your saw

Do a search and you find out what Lake thinks about this
Thats who I got the info from

 

[Lakeside53]

My local stihl tech advised me that there is no reason to put on new caps if you are removing the tabs and that the carb screws should not move. For years I have run my saws without the caps and nothing has ever moved. Heck, for years saws did not even come with caps. I would be interested in hearing what Lake and some of the other experts think about leaving the caps off.

Yes, if you are removing the tab, the old cap will generally be fine, BUT they often get damaged and loose when you remove them to cut the tab. They are only 50 cents each... It's not the tab that stops the needles from rotating, but you do need a positive cap lock on the needle if you are wanting to adjust them.

Walbro and Stihl both insist that the caps must be on to stop the needles from moving. Older saws without caps had springs under the needles to stop them rotating - carbs with caps do not have springs, but have tiny barbs (on the HD carb type of limiters) to stop the caps for coming out. It's not possible to put springs on the newer carbs as the needle head is too small to capture the spring. The o-ring seal on the base of the needle has nothing to do with stopping movement of the needle. Luckily the needles tend to rotate out so you just end up with a richer and richer running saw.

The BR420 blowers use the same carb type as the 044 etc, and I have watched the H needle rotate at certain RPMS...

As you indicate.. if you don't want the limiting action, the easiest solution is to simply slice off the lock tab and pop the cap back on - then you have full adjustability.

I replace caps on customer saws (hey, they are all out of adjustment. wonder why...), and keep them on my personal saws.

 

[KindlingKing]

Lakeside,

Thanks so much for easing my mind on my rpm question. With the dual port, a properly tensioned chain on the 36" bar, clean air filter, and this nasty California "ethanol" gas, my saw is turning 13,200 rpms. I'd love it if I could turn about 500 rpms less (ease my paranoid mind on melting a piston).

I've only got 2 tanks through the saw. As the rings seat, will you expect the rpms to increase or decrease? significantly? If not, I may not have to cut the tabs on the limiter caps? I'm at sea level and will use the saw 50:50 hear at sea level and at 3,000 to 4,000 feet. Don't think its possible for me to buy ethanol free gas in good ol' California anymore, so am stuck with the extra rpms..... at least until I pull the caps. Thanks!

 

[Lakeside53]

The max rpm will increase slightly as the rings seat.

 

[KindlingKing]

I'll keep a close eye on it with the tach. Probably gonna get the new limiter caps just to make sure I don't fry a brand new saw.

 

[59Billy]

The way I done mine........I bought the cap remover and new caps
from a Stihl dealer, Then removed rubber boot on the side where you
adjust the carb, it prys out......helps if the boot is warm. Used the tool
to remove the caps, cut the tabs off the new caps and installed.
Tool and new caps cost less than $10 I think it was more like $7
The saw is worth the money and with new caps its worth the piece
of mind, that they wont move while using the saw IMO

I will get the part numbers in a min or two for you.

Cap puller...5910 890 4500
caps..........4203 121 2700

Your advice is spot on here -- I just did mine. as you say, the grommet pries right off, and it goes on with very little effort. At my dealer, the caps were 55 cents, and the puller a mere 3 bucks. The DP cover was $42, so the whole mod didn't cost me $50.

so, thanks for the pointers.