Chainsaw Repair

I feel the easiest way is to pull the tank. Take off the clamp and use a screwdriver under the edge of the manifold and pry it off. On the carb side pull the ring off the od of the manifold and the sleeve in the id of the manifold. Then push it threw the housing. On install on the cylinder side you have to make sure the little tab on the manifold is to the right of the center line of the cylinder. Then install your clamp. To put it back through the housing use a length of string around the od of  the manifold  feed the end of the string threw the hole in the housing and pull it gently in to position. Also while you are there I would also replace the impulse line that is right below the manifold. One more thing I always use a little 2 stroke oil on the mating surface where the carb meets the manifold, seems to help it seal better IMO.