Reply To: evinrude 5.5 runs but max power is too low

[Don]

Are you sure it is running on both cylinders?  Have you drained/inspected the gear lube?  These gearcases have a pesky shock absorber that likes to expand and bind up the gearcase.  Also, make sure this engine has the correct pitch prop.  The 7.5hp prop looks identical, but has a larger pitch.