Check the points gap, Clean and reset the poitns to 014 in.
The 1972 85Hp should be equipped with a points distributer but it could be replaced with a electronic one with preamp.
You can check for spark by setting the #1 (top) cyl. in TDC. Throttle at idle and then the curve at the disterbuter pully should line up with the flywheel rim.
Loose the white/black wire at distributer, turn on the ignition and strike the wire to ground. Each time you strike it the #1 sparkplug should spark.
