Here's an update that might be of some help to someone.
I've decided to install somewhere between 5 and 7 cu ft of foam under the motor
My local dealer has a good rep. He says that this is a significant issue on the older ones. Recommendation now is to inspect and/or replace every 250hrs.
You must install the plug wire and boot then install the coil tak a couple pics so you know how it goes back together on the bottom of the plate.
Something's not adding up with any of your engine numbers. What area do you live in?
From what I'm seeing thus far the 9.8's would of
Install another prop.-----Not likely a slipping clutch on a Mercury motor.