'1995 OMC Cobra 5.0L - Power Steering issue - outdrive occasionally oscillates - generally at idle

Have a '95 Four Winns with 5L OMC Cobra with a steering issue.

Sometimes the outdrive wants to oscillate back and forth, generally only happens in neutral or at very low speeds.
If I turn right or left it will generally stop the oscillating.
Issue seems to occur most often while steering is centered or near centered.

PS fluid level is fine.
PS belt is fine.

Any ideas what might be causing the problem?

Thanks

belt is tight, flush the pump and put fresh fluid in.

Doesn't fix it then a new pump.

Thanks chiefalen, I'll try that!

Now is a good time since I have several other maintenance issues that need to be cleared up as well.

sounds like a tight u-joint - I'm not too familiar with the later Volvo/OMC era drives but I would look in the driveshaft bellows for water

Power Steering is working fine now. I removed what fluid I could by drawing it out of the pump from the fill opening.
Drew out what I could, replaced it with fresh, ran the boat briefly, moving the steering back and forth, shut it down and repeated this 3 times.

Power steering is fine now, no hunting at all.

Hystat, the bellows had moisture in it, bellows looked fine, but I installed a new one anyway.
Greased up the U-Joints real well and it seems to be fine now.

Son took the boat out yesterday and everything was fine.

Appreciate all the help.