Hi,
Your Stratos uses a manual fuel selector to switch between tanks. These switches have been known to cause restrictive problems such as the one you describe.
Does the problem exhibit itself regardless of which fuel tank you select?
I would also look for a boat mounted fuel filter, If there is one in the boat it will look similar to a cars oil filter. This filter or the mount it spins onto can also be the cause of your restriction.
Finally, the fuel line itself may be bad, You may not see any issue from a quick visual but it is not uncommon for the inner wall of the fuel hose to collapse on itself which will also cause a restriction.
Marine Mechanic
Evinrude Master Technician with 27 years of experience.