Re: altinator?
A 35 Hp is not shown in the BRP parts catalog for 1985 ...
However I would say it is pretty certain that if it was built originally with electric starting then yes it will have a stator coil and rectifier. If it was a rope start model to which electric starting then it will not have unless they have also been added.
Look for a rectifier. A round thing about 1 inch diameter and 1 inch long mounted on a sort of triangular two bolt flange on the side of the powerhead with three yellow wires and one red wire going to a nearby terminal block. (see picture below)
If fitted with a rectifier and stator coil then it should be wired so that battery charging is automatic.
Check your battery volts. If it is being charged they will rise from the initial reading once the engine is started and revved above idle.
If you find the rectifier is fitted but the battery is not charging then a faulty rectifier is the prime suspect.
The rectifier looks like this