1972 85HP Johnson (85ESL72) New Distributor Cap Fitment

[1963 Hydroswift]

I have a 1972 Johnson V4 85HP (85ESL72) Had an issue with the timer base sticking only when motor was hot which was caused by a severely worn distributor cap. (After cleaning and oiling as chronicled in multiple other threads, I still had the issue, so I ran the motor until it started binding again, removed the distributor cap and the timer base instantly moved with very light finger pressure again.) I've purchased a new old stock distributor cap which matched both the parts diagram for this model and the one being replaced which was previously on the engine. Only upon receiving the new distributor cap did I realize how staggeringly worn the existing cap was. Problem is, the new distributor cap doesn't fit onto/into the machined bosses on the top of the crankcase the same way the old one did. The old one would sit down flat on the machined surfaces (3 each), and was held concentric with the crank by the raised portion which is just outboard of the stator retention screw holes. The new one sits on top of the raised portion, not down in between them. I don't want to tighten the 3 stator retention screws and crack my new cap, but it seems like it shouldn't go together as is. The old cap has some worn looking notches in the perimeter at each location which cause it to fit snugly centered between the raised bumps. The factory service manual only says "making sure cap is properly seated" and then lists the torque value and a loctite spec for the 3 stator screws. Is there some kind of initial install procedure for a distributor cap (involving removal of plastic locally to allow it to sit down on the machined flats) that only has to be performed the first time a new cap is installed? The last thing i want to do is make the new cap look exactly like the old one and as a result duplicate the binding problem I'm trying to get away from. Any experienced help would be greatly appreciated.

 

[racerone]

Nothing touches the distributor cap when the motor is running !!----Therefor I do not understand how the cap can be WORN.------Was this motor ever apart ???---Something is assembled wrong !!------There has to be more to this story.

 

[racerone]

Should fit right out of the box.----No modifications need to be done.

 

[1963 Hydroswift]

The wear I'm referring to is that on the old cap, the pickups are completely flush with the inner mold line of the cap, and there is a circumferential crack running between all the contacts. On the new cap, no crack, and the brass(?) pickups sit proud of the inner mold line of the cap by approximately .050". The motor has never been apart to my knowledge other than the times I've taken the cap off for points gap check/adjustment. I've owned it for 10 years with nothing but standard preventative maintenance, but I don't know of it's history prior to that. This motor has been running regularly with no history of this issue until late last season. Since it was a heat related issue, I checked running temps first, but all cylinders are even, and warm not hot to the touch when going down the lake. I know this is not super scientific with therm sticks and everything, but there is nothing here that leads me to believe there is anything different about the cooling systems operation than the previous decade I've owned it. The hand on each cylinder head is a thing I usually do at the beginning of each season as a simple sanity check that things are cooling evenly, and all cylinders are contributors. Although both part numbers of distributor cap are stamped the same, something has changed dimensionally about the old one, as evidenced by the stator fit difference between the new and old. If I can get some pictures of the old, new, and the new sitting up on the bumps, and not down on the flats, I'll post them here for additional supporting information.

 

[1963 Hydroswift]

So, the above picture is of the old cap. It's been notched, either intentionally or simply through vibration and wear (seems unlikely) to sit down in between the cast bumps on the top of the motor, and down on the machined flats containing the threaded holes for the stator retention screws. New part which is stamped in the plastic as the exact same Johnson OEM part number and is NOS, does not have these notches, and as a result leaves a maybe .080 gap between the flats and the bottom of the distributor cap. Previously when opening this area up for points checks etc, I never even questioned if it was supposed to be that way, after I pulled the stator screws, it always just gently popped free and then fit nice and snug down in between those centering bumps when I put it back together. Now that I have a brand new cap, I'm starting to question whether or not it was ever right? The second picture is the motor with the new cap mounted. All three bosses are the same way. Anyone with knowledge of how this should really work would be greatly appreciated.