Yamaha 150hp very stiff hydraulic steering under load conditions

[Padraig Cooke]

Hello
I have recently purchased a 5 year old RIB with a Yamaha 150hp 4 stroke outboard, with approx. 100 hours. It has a Hydrive Commander hydraulic steering system.
When the boat is off the water, or on the water underway at low speeds (less than about 8 knots) the steering is easy to operate and feels normal.

However when the rpm is increased and the engine is put under higher loads, the steering become extremely stiff in both directions. After some testing I noticed that when I trim the engine up somewhat the steering feels normal again. Without any trimming at high speeds the steering is EXTREMELY difficult (to the point of being dangerous) to operate in both directions. The boat is NOT pulling right or left, so I am confident that this issue is not related to the trim tab.

I would like to know if this is normal, or do these symptoms indicate some kind of problem with the steering? I would be grateful of any considered advice from all the Yamaha experts out there.

Thank you,

Padraig

[Jason2tpa]

Not normal and def an issue with the hydro steering. In my experience, when it locks up like you’ve described it’s heading towards complete steering failure due to hydro leak. Are you able to visualize/inspect the length of hose from helm to hydro unit?

[99yam40]

I would think that when trimmed up properly and it is OK, why worry about running not trimmed properly?
could there be loads on some parts that at out of normal trim/ strain that are harder on the system?

[Padraig Cooke]

Thanks for those comments. I have checked the hydraulic oil level at the helm and its seems to require a topup. No obvious leaks anywhere. I'll top it up and see how that goes.