Ironic you came across a Grumman. I have 1989 Grumman Renagade, 16ft, 60inch across the back deck (i guess that would be the beam)
I bought mine in 2006 from a man that was no longer healthy enough to ride in boats. I was a lucky guy that day. He had replaced the motor and the trolling motor a year earlier, putting on a 4 stroke 40hp honda and 32lb Minn-kota. I jumped all over that deal.
Since then I have added a recirulator to the livewell, replaced 90% of the wiring, repainted it with a case of spray cans.
I love the boat it gets me every where I need to go.
I was never able to locate any schematics or manuals. If you do please share.