Re: Power steering
Most pontoon boats with your size motor go with the Baystar hydraulic steering system--if they're going to replace cable steering.
At 150 hp, they'll use a stronger version called SeaStar. When they get to 200+ horsepower, it'll be the SeaStar system with a $1,700 power steering booster. If you went to a Mercury Verado engine, they can be equipped with an internal power steering pump/booster.
It's the power steering equipped boats that really steer good. Unfortunately, they come at a $3,000 price tag--after labor.
If you're still running the cable type steering, make sure the grease fittings on the cable are lubricated. Or, get a bigger steering wheel.