[LIforrelaxin]

So 1st don't get overly concerned yet. The boat just came out of storage. 2nd the Marina should have treated the case in the tank appropriately, but as mentioned condensation can happen....

You mentioned you have filled the tank, I would run that tank through, as long as your not having any trouble getting to WOT. it is likely what you are experiencing will go away. It has been a cold damp spring thus far, something Outboards notoriously don't like.

Now if you are on your sixth season with the boat, it is likely a good time to run something like Gum-out through the system... Also regardless of manufacture recommendations new plugs should be in the plan... (although before doing the plugs I would run through this first tank of gas).....

Now water separating filters are mentioned, here while I agree they can help, they generally aren't needed if you are running you boat enough. Having said that, since the newer models of pontoons, like to put the gas tank down in the center tube, I believe adding one, could be a good idea.... however they themselves can cause additional problems.....

Anyways that is it for now... hopefully your issue will not put a damper on your summer.