I am looking at a 20' 1981 Prusuit tiara with a V6 OMC sterndrive. I can't find
a serial number on the engine and I don't know if the drive is a 600 or an 800.
I realize that I'll probably need to re-power it soon but the motor runs great
and
at the asking price, I only need to get about 1 season out of it to make it
economically feasible.

Here's the problem:
The drive unit turns to the left fine but won't turn much past center to the
right.
The steering system is a double cable. The helm has a drum with a half dozen
wraps of cable around it. The termination on the outdrive is completely sealed
so I have no idea how it's connected.

My questions:
Does anyone know if there is a way to test whether it's the cable or the
outdrive?

Assuming it is the cable, can it be changed from inside the boat? The boat is
currently in the water and I don't want to have to pull it to change the cable.

Thanks in advance,
Vinny