Hi, I'm new here so I apologize for any lack of etiquette.

I recently acquired a 1990 20 foot Stratos 201 pro DC and a Evinrude 150.
I have many questions but I'll just ask a couple.
The model of the motor is E150ELEIS spitfire.
The serial number is G02977906.

The spark plugs that are currently in there are QL78YC.
The schematics on Evinrude's website say that they take QL77JC4. So should I change to them?

Second question,
The clear plastic sleeve on the pickup roller crumbled and fell apart. I ordered follower
Part #: 0432639
Qty: 1
USD$ 7.96
and
a O-RING, Roller & sleeve
Part #: 0324678
Qty: 1
USD$ 3.11
Can I just put these things on or is the timing link/sinc gonna be screwed up?

Thanks for your time.
John