Re: Dismantling controls- 1972 Johnson 65 hydro-electric
Pretty simple.
Remove the unit from the side rail, mounting plate or however you have it attached to the boat. Remove three countersunk screws on the back side. You will need a number 1 philips head for this.
When you split the halves, be careful of a cam roller that fits on the throttle lever in the box. It looks like a "ball cap" (my term) and it fits within a groove (lever cam) in the throttle handle's base.
There is also a plastic guard (lead retainer) in the box - they tend to get brittle, so be careful of it. The same is true of the "ears" on the shift switch, so be careful of that. In general, if you don't have to remove something, don't - leave it alone.
As long as you are going to be opening the box anyway, do the hot horn test first. If the horn is bad, you may as well replace it too. The replacement horns are stupidly expensive, but you can still get them. That said, there is a kit for the newer control boxes that includes a horn. Sometimes the dealers don't need to use the horn in the kit, so they have extras lying around. I replaced mine an my dealer actually gave the thing to me, because I do a lo of business with him.
The new horns are red (not "silver) and are smaller than the old one. You can still use them though. There is a plastic mounting bracket for the horn (which also might be brittle, so ber careful) and you can place the new horn within it, running the wires under the the bottom, to hold it in place.
Your new key switch will probably have two leads for the purple circuits, instead of the one that was on the original switches. Both of these leads are tied to a common "bar" (you'll see what I mean when you look at it) and are there, just because there are a lot of purple wires and having two posts instead of one, makes life easier.
Thgat's about all I can think of, off the top of my head. I'll post again, if I think of other issues/concerns.
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