MS200t C1Q Carb rebuild issue

[sloch24]

Hello all... I've been away from the forums for a while (Darn work keeps getting in the way of my Stihl-Life).

Anyway, I picked up a 200t that ran okay, but would lean out and die after a minute or so of no throttle. So... I removed the carburetor, cleaned it, and adjusted the metering lever to flush with the Zama tool (it was a little low). I then reassembled the saw, and now it only runs when given full throttle, and the carburetor is spitting fuel out the back. I took it back apart, and checked everything, and even replaced the needle and metering lever from another c1q and still the same problem.

Now I'm confused, so I took the carb off a known good 200t, and it runs and idles perfectly.

What I need to know is, what could I have done to this carb to make it run so erratically and blow gas out the intake? I've done dozens of these, and I've never had this problem. The diaphragm isn't the greatest, but it ran okay before. I tried 2 other diaphragms that were in similar condition, with the same result. I'm just glad the carb is easily removed from this saw..

Any suggestions short of buying a new carb would be appreciated.

I should also mention that running the H and L screws all the way in does not stahll the saw, it keeps spitting fuel and at times will run rich and surge.

Thanks in advance!

 

[ptjeep]

How much fuel is being spit back? Two strokes will spit some fuel back out of the carb, that is normal but not an excessive amount. Any chance the accelerator pump is bad? Its a common problem on 200T's.

 

[chainsawman2011]

ms 200 carb issue

Hello all... I've been away from the forums for a while (Darn work keeps getting in the way of my Stihl-Life).

Anyway, I picked up a 200t that ran okay, but would lean out and die after a minute or so of no throttle. So... I removed the carburetor, cleaned it, and adjusted the metering lever to flush with the Zama tool (it was a little low). I then reassembled the saw, and now it only runs when given full throttle, and the carburetor is spitting fuel out the back. I took it back apart, and checked everything, and even replaced the needle and metering lever from another c1q and still the same problem.

Now I'm confused, so I took the carb off a known good 200t, and it runs and idles perfectly.

What I need to know is, what could I have done to this carb to make it run so erratically and blow gas out the intake? I've done dozens of these, and I've never had this problem. The diaphragm isn't the greatest, but it ran okay before. I tried 2 other diaphragms that were in similar condition, with the same result. I'm just glad the carb is easily removed from this saw..

Any suggestions short of buying a new carb would be appreciated.

I should also mention that running the H and L screws all the way in does not stahll the saw, it keeps spitting fuel and at times will run rich and surge.

Thanks in advance!

c1q zama that spells junk carb buy a new one. more than likely ethonal ate at the aluminum
in the carb like all the other zamas. there is no saving it. believe me if I saved all the ones I have
replaced for that reason I could fill a few 5 gallon buckets. you didn't do anything wrong the gas
companies do with all the ethonal. Sorry I Know It doesn't make the carbs any cheaper to buy.

 

[sloch24]

How much fuel is being spit back? Two strokes will spit some fuel back out of the carb, that is normal but not an excessive amount. Any chance the accelerator pump is bad? Its a common problem on 200T's.

Enough to wet my hand with the air filter off. I could buy the accelerator pump idea if it hadn't run and taken the gas very well before I cleaned it. It actually ran almost perfect before I cleaned the carb, it just leaned out and stalled if you set it down. It doesn't do that at all with the other carb, so it's definitely a carb-related problem. I don't get anything but fine vapor spray back on the known good carb, the other one actually "spits" fuel out of the back.

 

[ptjeep]

I feel for ya, carb problems suck big time. I wouldnt give up on it yet, cause a new carb will run you $90-$100. Good luck.

 

[sloch24]

I feel for ya, carb problems suck big time. I wouldnt give up on it yet, cause a new carb will run you $90-$100. Good luck.

Thanks... I'm not done yet.. I may just bend the metering lever back to where it was and see what happens. Maybe that was the previous owners fix to get that carb to run... Tomorrow is another day.


I'm still open to any other suggestions!!!

 

[TXLiquid]

Hook a vacuum tester to fuel inlet to see if needle is sealing.

 

[sloch24]

Hook a vacuum tester to fuel inlet to see if needle is sealing.

Yup, the needle is holding pressure. Last night I tried another carb I had taken off a 200t because of the accelerator pump issue, and it ran on this saw like a brand new carb. Weird.

Thanks for all the help and suggestions.

 

[hotshot]

Hook a vacuum tester to fuel inlet to see if needle is sealing.

Did you pull the low speed welch plug & check that the idle circuits were all clear of debris?

 

[bezza1]

The glue holding the welsh plugs in will collapse if the glue is the red stuff it is ethanol resistant and good but if its clear its the old style and falls apart all the time I replaced a carby on a 200t on Friday beacouse of it

 

[sloch24]

Did you pull the low speed welch plug & check that the idle circuits were all clear of debris?

Nope.. I've never gotten into these carbs far enough to remove the welch plugs. I suppose this would be a good time to start though. I still don't understand why it would be running with both screws H + L turned all the way in. I thought that was the only passage for fuel. Makes me think something is being bypassed somewhere, not clogged.

 

[hotshot]

Nope.. I've never gotten into these carbs far enough to remove the welch plugs. I suppose this would be a good time to start though. I still don't understand why it would be running with both screws H + L turned all the way in. I thought that was the only passage for fuel. Makes me think something is being bypassed somewhere, not clogged.

A loose plug will allow needle bypassing, directly into the idle pocket. I can't remember how
the C1Q main jet is circuited but I'll take a look.

I would go to their (Zama) website & study/read, they have an excellent tech manual.

Just use a small hammer & scratch awl (sharp pointed) at an extreme angle to pierce
the plug, it will pop right out.