Stihl 201 Tank Pressure

[Carhartt]

Got a 201 on the bench and wondering about some running issues. Claim is it falls on face in the cut and have to pull it out and bring back to RPMs again. Owner just doesn't get along with it, and I am trying to get him to love it. Muffler opened and timing advanced. So I thought id tear the carb off and give it a good cleaning. When I removed the fuel supply, fuel came spraying out hard(after I cracked the cap and resealed). I am wondering what a fuel tank pressure and vacuum should read? Could too much fuel tank pressure cause an issue? Maybe if the needle valve is seating 100 percent tight. Id love this to just be a simple tank vent replacement.

 

[Lone Wolf]

Got a 201 on the bench and wondering about some running issues. Claim is it falls on face in the cut and have to pull it out and bring back to RPMs again. Owner just doesn't get along with it, and I am trying to get him to love it. Muffler opened and timing advanced. So I thought id tear the carb off and give it a good cleaning. When I removed the fuel supply, fuel came spraying out hard(after I cracked the cap and resealed). I am wondering what a fuel tank pressure and vacuum should read? Could too much fuel tank pressure cause an issue? Maybe if the needle valve is seating 100 percent tight. Id love this to just be a simple tank vent replacement.

Should hold pressure when tested but not hold vac , test at the fuel line with tank empty and leave the breather on.

 

[AVB]

Your carburetor fuel inlet should be to hold at 11.6 PSI tank pressure and the tank should not be holding a vacuum.

 

[Lone Wolf]

Your carburetor fuel inlet should be to hold at 11.6 PSI tank pressure and the tank should not be holding a vacuum.

What are you saying the tank pressure should hold or not hold?

 

[Lone Wolf]

Got a 201 on the bench and wondering about some running issues. Claim is it falls on face in the cut and have to pull it out and bring back to RPMs again. Owner just doesn't get along with it, and I am trying to get him to love it. Muffler opened and timing advanced. So I thought id tear the carb off and give it a good cleaning. When I removed the fuel supply, fuel came spraying out hard(after I cracked the cap and resealed). I am wondering what a fuel tank pressure and vacuum should read? Could too much fuel tank pressure cause an issue? Maybe if the needle valve is seating 100 percent tight. Id love this to just be a simple tank vent replacement.

Was this saw compression tested?

 

[Carhartt]

I did not chk compression but I will. If I was a betting man id bet a lot on it is fine. Not many miles on saw and drop pulls hard.
What is your suspicion on the compression or lack of compression?

 

[blsnelling]

As you experienced, the tank will hold pressure. Stihl uses a true one-valve.

 

[Lone Wolf]

I did not chk compression but I will. If I was a betting man id bet a lot on it is fine. Not many miles on saw and drop pulls hard.
What is your suspicion on the compression or lack of compression?

Just so you can eliminate that as a problem ,do you have a gauge that will screw into that smaller 10 mm thread?

 

[Carhartt]

So high fuel tank pressure will not effect way saw runs? I did not find anything obvious inside carb.

 

[Carhartt]

Just so you can eliminate that as a problem ,do you have a gauge that will screw into that smaller 10 mm thread?

I ordered a conversion reducer a while back. Now can I find it in 1 of the drawers?

 

[Lone Wolf]

I ordered a conversion reducer a while back. Now can I find it in 1 of the drawers?

If the Schrader valve ain't at the tip it wont be accurate.

 

[Chainsaw Jim]

Change the fuel filter, kit the carb.

 

[Carhartt]

If the Schrader valve ain't at the tip it wont be accurate.

Good call Lone Wolf.

Change the fuel filter, kit the carb.

I will take care of the simple stuff for sure.

 

[SteveinUT]

My 026 is doing the same thing. I just ordered a new tank vent and fuel filter. Hopefully that will cure it. It sure seems like mine is starved for fuel within a few seconds in a cut. For a saw that the previous owner said had been "fully serviced" I'm finding out quick that he was full of *s-word. All the more reason for me to stick with used saws from folks here and not local...

 

[Lone Wolf]

You can test the vent with a vac press tester.

 

[Carhartt]

I replaced, rebuilt and reassembled everything over the wknd. Seems to run fine. Now just hope the owner feels the same way.
I did a cut comparison against a few 200Ts and felt it was right there with them.