I just bought a new to me 2003 Avance with a Yamaha 250 outboard that has Seastar hydraulic steering. Doesn't seem to be working properly, meaning very hard to steer while running. What are the proper diagnostic steps? I'd start with checking fluid, however just wondering if there's a common problem or a flush or something that is a good starting point. Thanks everyone! Boat and motor are 2003. I assume steering is the same age also.

Bleed air and add fluid. A turkey baster works good for adding fluid

Thanks! What kind of hydraulic fluid do I need to buy?