Steering without motor running
 

Can a full hydraulic steering system boat (twin engine) be steered if the motor with the pump is not running?

That's what I was thinking. Fella in the Formula forum with a 400SS says his steering is easy to turn but the drives don't move until the motor is running. Think there is something wrong with the system

I doubt anyone would design steering to not work if a motors dies or you toss a belt.

Something is definitely wrong. The steering should work regardless of if the engine is running or not. As mentioned, it's just VERY hard to turn, but it will turn.
Eddie

I upgraded to a full hydraulic steering in my Donzi last year.
Regardless of manufacturer you can steer with the motor not running. The helm station acts as a pump and will move enough hydraulic fluid to be able to steer the vessel.
The fail safe is a two pump system but it’s quite a bit more expensive.

Thanks all for the verification. I linked this thread with the Formula forum thread so he can have a look

Yes, with full hydraulic steering the helm is still a positive displacement pump (orbital valvle). The power steering pump is just a power assist. Like the power brake booster for your brakes on your car. They work without the booster, but you'll definitely know it.
If a seal is blown in the helm it might not work properly when pump is not running. The pressure from the pump and volume may mask this, or if air is in the system.