Stihl MS260 tank pressure

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vert33

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edmonton alberta
I’m lost guys, I have a MS 260 that I bought as a project. It ran when I bought it but the cylinder was scored up. I replaced the cylinder and piston, along with the fuel line and filter.

Now I’ve had a little problem getting the ole girl to run. It’s floods immediately now. What I’ve found and what I’m curious about is when the carb is disconnected from the fuel line/saw. The fuel in the tank(doesn’t matter if full or 1/4 full) will purge out the fuel line.

Is this normal? I figured the vent was the issue but when I read up on it, It sounds like it’s a one way vent(only lets air in to replace used fuel but not out)

obviously if I pop the vent off or the cap it doesn’t build pressure and it doesn’t purge out. But with both on it just keeps pushing the fuel out of the fuel line.

I have not needed with the needle of the carb other then opening the carb up to make sure it was clean.

Am I correct About the one way vent? and if I am what’s causing the purge.
I’m thinking about buying a new cap and vent but I just don’t see how they would be the issue. Maybe I’m wrong and there is no issue with this?(worked on multiple small engines and never had this problem)

It’s only 15ish degrees Celsius here and in the shop and has been for a while so it’s not from temperature expansion

Any help would be wonderful and much appreciated!
 
Normal for fuel to push out the line when disconnected, fuel wants to be a vapor, youll find any disturbance of the resting tank makes the flow out much worse.

Sent from my SM-G996U using Tapatalk
 
Tank pressure normal. Try a run without the airfilter before you do anything else. The choke flap is notorious for failing and being sucked up against the carb which would cause flooding.

In addition, pressure test the carb to make sure the needle and seat are sealing and holding at least 15psi. Apply the pressure though the fuel inlet elbow with the carb fully assembled. Make sure metering height is correct and that the metering plate area isn’t caked with sawdust (which would hold the needle off the seat).
 
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