Help with 200t tuning...

Bermy

Acolyte of the short bar
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May 3, 2008
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My 200t sits for about 7 months...I run it dry before storing.
Fill up with new fuel and off it goes.

This time however it is hesitating on low throttle, I've reset the jets to factory, and tried tuning the low speed, seem to get it picking up well then after a bit of use it starts to falter again. Idles ok, but coughs and spits when I give it throttle, before settling to cut, runs fine at the top end.

Any suggestions?
 
Fiona your carby diaphrams sound like they need changing, probably stiff from old age or fuel quality.
Is this the 200 I sold you?
 
Another thought in addition to the soft carb parts .200T's are known to get bad seals .Sometimes because of bad bearings .I'd venture a guess that bad seals have burned up more cylinders than bad carbs .

This model may be the only one made that is user friendly for splitting the case because the roller bearing mains are slip fit not the heat shrink type used on other Stihl models .Stateside seals and bearing are around 60 dollars US .Probabley a tad bit higher in your neck of the woods .If you need parts give a shout and one of us will mail them
 
Al , Bermy said it runs fine at WOT but just doggy on the bottom end. If it had a leaking crank seal there would be all kind of lean erratic running condition especially at mid range rpm.
Bad diaphragms wouldn't be soft , they would be stiff making poor fuel pickup at lower rpms.
 
It sounds as it needs more fuel. If it responds to adjusting give it a little more on L as in adjusting needle out a bit 1/4 turn is plenty.
That will give it more on Accelleration and Low rpm.

If it doesn't respond/improve to this, do the same on H. They work together, H and L if H is set too low it restricts L.

If this doesn't work you have a fuel/carb problem as it sounds.

Start at beginning in tank, look at filter, hose and tank. Go further and see all is OK. If you get to carb and all is ok this could do with a checkup.

Membranes can get to soft, too hard get holes, parts can come loose and gaskets break.
 
Im thinking a saw run dry then left to sit for a long time then run later may have some hard or stiff diaphragms if they haven't been replaced for years or are the originals. I found sometimes if you let the saw sit for a few days the fuel will soften up older diaphragms and then the saw will run fine. She did say it ran fine before putting it in storage.
So what's the history on those diaphragms Bermy?
 
I have seen membranes that got stiff after storage. Most likely they would be so in any case. I have seen more that has been stiff with fuel in them.

As fuel pass thru I believe oil get stuck on the membrane surface. Run dry or not it will still be there and if oil is aggressive it will eat membrane or make it soggy, if it is drying rubber it will be stiff.

Another benefit we have here from running Alkylate with a not aggressive oil....

On saws run with oil that dry them out and make them stiff you sometimes can soften them up, but not all times.
Sometimes there gets tiny holes or cracks and they are untight, sometimes WD40 or a good two stroke will do the trick.
 
You missunderstood Willard " Another thought in addition to the soft carb parts "meaning the replaceable parts ---diaphragm,check valse assembley etc .I agree though the carb is where I'd start .
 
You missunderstood Willard " Another thought in addition to the soft carb parts "meaning the replaceable parts ---diaphragm,check valse assembley etc .I agree though the carb is where I'd start .
Al, I know what you're saying. I have seen soft degraded diaphragms and other internals, but from what I see is 9 out of 10 parts from commercial used saws are stiff hardened parts. Yes I agree some toxic fuel mixes or a saw sitting for years still fueled up can turn a fuel line to mush.

But I think we're beating a dead horse here, until Bermy reports when was the last time a carb kit or even just the diaphragms were replaced we can't speculate any kind of diagnosis here. From her OP the saw was put away dry for 7 months and appeared to be running ok before that.....hestation off idle even after retuning tells me she has a stiff diaphragm problem

This is the main reason I hardly ever give advice on saw tuning over the net, information get all twisted around with all different opinions .....
 
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  • #12
I'm here!!!

Just working a lot and too tired to log on...

'Kay, this is a saw I bought new in 2005 (or 2007, will check in the morning) not your saw Willard!, I bought three saws from Jim Courville when he worked at Mayers.
It's never had any carb issues before, no replacement parts, only thing ever wrong with it was a blocked fuel tank breather.

Last year I ran some old gas in it when I first got it out of storage, then mixed up fresh, by the end of the summer it was starting to have these symptoms. Then this year, fresh gas from the get-go and its wobbly. The flippy gas cap was buggered, just would NOT seat and very stiff, I ditched it had a spare, seemed to help a bit, thought maybe there had been a seal problem with the cap...but its going boggy again at low.

I'll write down what you've all said, and spend some time tuning it, only done some quick tuning before work.

My other two saws that I store, 260 pro and 361 are fine, same treatment, same gas.
 
A 7-9 year old that never had the carb rebuilt is due for at least a simple diaphragm carb kit.replacement.
Easy to do , remove carb then replace both top and bottom diaphragms and gaskets.
For a few extra dollars you might as well get the full kit and replace the metering inlet needle too with spring and fork.
But to be honest just to save alot of headaches I just buy a new carb and its good as new.
 
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  • #16
I doubt our dealer will have a kit or a carb, but I'll check.
Will try to re-tune it first though.

Thanks for the help guys :)
 
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  • #17
So I fiddled with the idle setting...that seemed to solve the problem, once it got warmed up it ran just fine for the rest of the day, low and high...honestly I didn't touch anything else!
 
So I fiddled with the idle setting...that seemed to solve the problem, once it got warmed up it ran just fine for the rest of the day, low and high...honestly I didn't touch anything else!
Just what I figured ....let the carb diaphrams soak with the fuel mix for a day or so and they soften right up. But you better still change them.
 
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  • #19
I got to hear it the other day, someone else was using it...ran and idled just fine, and has that cool 'snarl' of an opened up 200t!

Hearing it at a distance helps...
 
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