Stihl MS200T Strange Running Condition

[pennsdalerepair]

I have an older Stihl MS200T that was given to me a while back. It was hard starting, and died out after a few minutes of rough running. So, I decided to give it a good over haul as it's previous life was apparently hard. New cylinder, piston, rings, gaskets, intake boot, fuel line, crank seals, plug. Carb replaced a short while back by PO. It starts up fairly easily, but no matter hoe I adjust the carb, after a minute or less it dies out. It will idle fine, but other than that it just won't run the way it should. Any thoughts on this, please?

Thanks!

 

[Giles]

I would go through carburetor to be sure it isn't stopped up.
Also check fuel line, impulse hose and tank vent.

 

[tomdcoker]

I know that you listed a plug as a replacement part, but the first thing I would try is the plug and then the second would would be the muffler screen. Tom

 

[Chainsaw Jim]

200t's seem to build up carbon on the muffler screen pretty fast. The fuel filters need replaced more often than any other model I've serviced.
Try running without the air filter to eliminate it as a problem too.

 

[pennsdalerepair]

Guys...
I replaced the plug AGAIN, removed the air cleaner, new fuel filter...on to cleaning the muffler screen. Also found a thread about the fuel cap not sealing properly, causing a loss of pressurization. So, going to remedy that issue and going to go through the carb again thi week, once I return from EFI training. Will keep you posted on progress. Thank You ALL!!!!

 

[Tom Schaech]

Hi everyone...

Guys...
I replaced the plug AGAIN, removed the air cleaner, new fuel filter...on to cleaning the muffler screen. Also found a thread about the fuel cap not sealing properly, causing a loss of pressurization. So, going to remedy that issue and going to go through the carb again thi week, once I return from EFI training. Will keep you posted on progress. Thank You ALL!!!!

UPDATE: I went through the carb AGAIN...no issues found. I had another NEW carb on the shelf s I changed it out. I'm thinking there's an air leak somewhere, but I'm at a dead end. Starts up, hesitates on "acceleration", can get it up to full RPM for about 15 seconds, then gradually loses power to where it dies. Will start back up. Carb is really sensitive to adjustment. I'm still thinking air leak, but next step I guess should be a leakdown test. Fuel cap is also new, as is fuel line and filter. Thoughts? Really like this saw and want to get it up and OUT of the shop!! Thanks!

 

[Tom Schaech]

Hi everyone...



UPDATE: I went through the carb AGAIN...no issues found. I had another NEW carb on the shelf s I changed it out. I'm thinking there's an air leak somewhere, but I'm at a dead end. Starts up, hesitates on "acceleration", can get it up to full RPM for about 15 seconds, then gradually loses power to where it dies. Will start back up. Carb is really sensitive to adjustment. I'm still thinking air leak, but next step I guess should be a leakdown test. Fuel cap is also new, as is fuel line and filter. Thoughts? Really like this saw and want to get it up and OUT of the shop!! Thanks!

 

[Tom Schaech]

I'm going to replace the tank vent assembly. This saw had a hard life prior to my owning it. Also going to attempt to pull the muffler apart and clean the screen. Will advise...

 

[Tom Schaech]

I'm going to replace the tank vent assembly. This saw had a hard life prior to my owning it. Also going to attempt to pull the muffler apart and clean the screen. Will advise...

 

[Tom Schaech]

Couldn't stop thinking about the problem with this saw, so I ventured back into the shop to pull the muffler. Lo and behold, the internal muffler screen was blocked completely 4 out of 6 ports. Cleaned it thoroughly and reassembled. Pulled the tank assy off the saw to remove and clean the vent. Possibly plugged; noted new vent and valve ordered. Looking at the intake boot closely, I see where it had MELTED partially and opened up!! Thinking this also leaned out the mixture o where there could be piston scoring; I thought I would look closely. SURE ENOUGH...piston scored! Enough said. Ordered a "long block" to replace the offending parts. I'll have a brand new saw once this is done!! Oh well, still a good deal-I'll have less than $175 in it. Not sure how or why the intake boot did what it did, but it is what it is...