1985 85hp o/b spark question

I'm had an issue on Saturday with the engine. I could only get 35/3600 RPM & 20 MPH (GPS) at WOT. I did notice after it was out of the water that I had for got to open the vent on the fuel tank. I thought that may be the problem. It was not, when I removed the cover I found the top spark plug wire was off, problem fixed, for now. I crimped the boot & it will stay on. The boot is shot & is wrapped with electric tape. I just got this boat/engine & was not aware of this. I thought I could just replace the boot & wire like on a car, but no, it go's into the black box (don't know what it is called), so I'll need to replace that as well. Do I need to replace all three at the same time? Or can I do just the one? Also, what is this part called & how much $$ are they? Can I just pick this item up at the local boat dealer? Thanks, Maxx

Re: 1985 85hp o/b spark question

Is there enough wire to put on a new end?Way cheaper!!!
You can get the coil at any MERCURY dealer.Gotta have mod# ser#
Sometimes they can be found on E-bay usually cheaper than the dealer.
Some of the guys here have parts.Someone might possibly sell you one.J

Re: 1985 85hp o/b spark question

Thanks, I think there maybe enough to do a new cap. I'll check ebay & the forum as well.

Re: 1985 85hp o/b spark question

You can pick up plug wire ends at napa , just recrimp and seal with clear silicon sealant