MS290 sprays fuel from cap and vent line at high RPM

[RossD]

I have a Stihl MS290. Recently cleaned carb and changed spark plug after saw was not starting. Saw now starts like a champ but is spraying fuel out of the fuel cap and out of the vent hose/cap when running. There is a lot of pressure in the gas tank. I tried running it with the vent filter off and loads of gas came pouring out while the saw was running. The cap is on plenty tight. Any ideas?

 

[RossD]

Alright, well, I'm a Fool. New cap fixed the problem.

 

[Patrick1903]

Why was it spraying out of the tank vent? Shouldn’t that only allow air in?

 

[stihltech]

Two vent screws in the vent line, no cracks and make sure the top of the line fits in the opening on thee cylinder shroud. The vent tube vibrating in the air will make it leak.