200T boggs down after cut - how to adjust?

[DeanBrown3D]

Hello all,

I've had an MS200T for some time now and after a cut (not even a heavy one) the saw nearly stalls, unless I blip the throttle a few times and max out its revs. How can I adjust this? I assume this is too rich, but not sure. Also please tell me which of the LA, H and L screws you mean, as I am not sure the difference between the LA and the L adjusters.

Thanks for any help,

Dean

 

[fishhuntcutwood]

"LA" is your throttle adjustment. You'll see it as a screw up against your throttle arm. The "L" screw is your low jet. The "H" screw is the one with the big, external limiter on it. I've posted pics of it somewhere on here before. I'm at work right now, when I get home I can post more detailed pics if need be.

Jeff

 

[Ekka]

Well, have you taken the screen out of the muffler?

If not, do that first then tune it. (unless you work in a dry forest etc).

2 screws close together up the top, one is for High speed air mixture the other for idle (L for low speed).

The screw at the bottom is for idle rpm speed.

Screwing in the H or L screw makes it leaner and out makes it richer.

I hold my saw flat out, screw in the H till it peaks and come out 1/4 turn, that's roughly right.

The L screw next to the H screw, again I screw it in till the idle speed peaks and come out 1/4 of a turn.

Then the rpm screw at the bottom is set so that it idles nice and the chain doesnt spin with the brake off.

I find you need to turn these screws SLOWLY, and things can change due to elevation, airfilter clogged, hot/cold etc, so take it easy.

If you have a rev counter it can make the job easier and you set it to factory spec but my ears are pretty used to how it should sound.

I hope this helps, and dont run saws flat out too lean for long or you'll be up for new piston and barrel.

 

[DeanBrown3D]

I haven't removed the screen.

The L and the LA - both adjust the low idle? Sorry, I'm still confused with what the difference is between these two.

 

[04ultra]

hope this helps..

 

[Lakeside53]

Two points from the posts above:

1) If you intend to use your spark arresting screen (don't get caught in western forests without one), put it back in before making the adjustments. If not you'll see an H drop of 500 or so rpm due to the increased back-pressure. It will have no effect on your problem anyhow.

2) One of the above mentions that your MS200T probably has limiter caps on the H screw. It just pulls off but be careful adjusting without it as the screw ends are easy to break. Pop it back on in mid-position after you are happy with the setting and you'll have plenty of future adjustment range.

..and, if you have a tach, set the H end to about 14 - 14.5k

 

[Lakeside53]

I haven't removed the screen.

The L and the LA - both adjust the low idle? Sorry, I'm still confused with what the difference is between these two.

The L adjusts the low speed mixture. If you make the mixture leaner, it will speed up, and richer (counter clockwise) will slow down. You need to get the correct setting such that it both idles well and accelerates smoothly.

The LA is just a fine adjustment of the throttle position - like pressing your finger on the throttle. It has not effect on mixture.

If you adjust the L richer, and the saw slows down, then the LA will get turned in a little to increase the idle speed.

You saw sound like it's running too rich... maybe on both L and H, or, it has a leaky needle valve or a stiff diaphragm. Try adjustment first though.

 

[DeanBrown3D]

Ok thanks its finally clear. So the LA is like the throttle adjuster on an older car, right, just a screw to pull the throttle open?

I can't see any caps on the screws, its a very small hole and I can see a flat head screw inside, but nothing else.

-Edit: Oh I see, under the cover I can see the stops.

 

[fishhuntcutwood]

Ok thanks its finally clear. So the LA is like the throttle adjuster on an older car, right, just a screw to pull the throttle open?

Yep.

And here's a pic of the limiter as seen from underneath the plastic.

http://www.arboristsite.com/attachment.php?attachmentid=31727&d=1141326685

It does come off with plier, or a screwdriver, or however you choose to get it off. However, like Andy said, go easy on it, or you'll snap the whole screw off.

 

[DeanBrown3D]

I adjusted both the H and L clockwise by around 1/4 turn. The screws were quite easy to move, as its only around 2 years old. I'll see how it runs soon.

Cheers and thanks for all the help,

Dean