I did replace all the external lines. But not the one inside the tank. I got the Topstar from my instructor second hand so I couldnt get the tank open. That is one consideration I will make this season before I fly the Topstar again.

With respect to the tank position, the tank centreline is almost at the same level as the carb, so I dont thinkthat it is the issue.

But can someone please answer whether the 2S engines can be mounted inverted?

Ameyam