I have a 20 year old 18 foot Glastron, with an inboard/outboard Mercruiser engine.  At low speed,  there is about a one second delay from when I turn the steering wheel before the boat starts to turn.  There is a narrow channel between two lakes where I have to go at idle speed, and it is very difficult to navigate.   At higher speeds - skiing and wake boarding - it steers fine.

I thought that this was just a characteristic of I/O engines, but my fishing buddies say that it should steer true, and that there is probably a problem with the linkage.

Any thoughts?

 

All boats handle differently.  Some respond quickly to steering input, while others are sluggish to respond and therefore need more steering input.  It varies with the shape of a hull, its weight, and other factors.

The same is true of course corrections.

Try running some of your buddies' boats, and see how they feel.

Unless you have a lot of play in your steering, there should be no lag in the actual turning of stern drive, and that should be obvious.

If you have hydraulic steering, the system could have air in the lines which would account for the lag time.  If that's the case, the system will need to be bled.

Being and I/O, I don't even know what kind of steering system you have.  Does it have a steering pump like and automobile and hydraulic system, or does it have an enclosed system like the SeaStar where the torque generator at the helm is steering pump.  It could just have cable steering for all I know.  

If it's and enclosed system like the SeaStar, as FishingRino stated, sounds like you have air in the system and it needs bled.  It has a pump, again, could be air in the system or the pump could be bad and not making pressure at low rpm, or pressure relief valve acting up.