Changing Plug Wires on a 1965 65 hp Merc 650

I purchased a boat w/this motor on it. It started so I bought it. When I got it home I decided to take a look at the engine, plus it would no longer start. I wiggled one of the plug wires and it came out of the boot. Took a look at the distributor and realiaed quickly I have no clue. The shop want $150 an hour to work on it, and I assume this is something I could do myself if only I knew how to swap the wires on the ditributor end. Any help would be greatly appreciatted.

Re: Changing Plug Wires on a 1965 65 hp Merc 650

Plug wires are threaded into the distributor. Don't try just pulling them out or you will damage the wires and/or the cap. Cap is expensive to replace, about $150 believe it or not.

The spark plug end of the wires is the typical push-on type, and the coil wire pushes into the coil. It can be removed by pulling the wire straight out of the coil. It may take quite some force to do so, especially if its been there for awhile.

Once you break the seal between the boot and the cap, the wire will unthread (usual right hand thread). I find it easier to remove the distributor cap from the distributor before attempting to replace the wires. The cap is secured to the distributor body by a single clamp tensioned with a screw and nut.

Take care not to damage to rotor when removing the cap. I believe it is one piece with the shaft and is VERY expensive if you have to replace it. I know that my 1970 motor is that way, but not sure if the 65 year is the same.

Re: Changing Plug Wires on a 1965 65 hp Merc 650

I pulled the wire right out of the end on my newly bought/used cap when I first got it. That's about the time I realized the coil wire threaded into the cap. I was wondering about the rest of the spark plug wires on the cap since I hadn't tried to take them off. I was hoping they didn't thread in like the coil wire because that means a lot more work. Fortunately the new switchbox/coil came w/ a new coil wire and the motor now starts so I haven't had to mess w/ the old spark plug wires yet.