Re: How many different Mercury switchboxes were made in the 70's
That switchbox will work 332-2986 A21 A22 A23 A24 A25 etc are all the same.All the (A21 etc.) is a supersetion.In the 70's inline 4 and 6 used the same switchbox no diiference except the 4 cylinder used what is called a 4 window disc,and 6 cylinder ones used a 6 window disc under the rotor.
Re: How many different Mercury switchboxes were made in the 70's
If it came off of a inline 4 all you would have to do is swap out the 6 window disk from your old trigger and your good to go.If it came off of a inline 6 you are good to go as well. 332-2986 (A whatever) good to go..
Re: How many different Mercury switchboxes were made in the 70's
It is off of a 4 cylinder, 65 HP. What is this window disk of which you speak, and how labor intensive is it to swap out, the window disk, not the switch box.
Re: How many different Mercury switchboxes were made in the 70's
The only difference in a 4 cyl and 6 cyl switch box is the old style tach sender which we don't use any more as the tachs are alternator driven so any 332-2986 A whatever will work fine. You are correct that the timing disc is in the distributor and the 6 window is for a 6 cyl and a 4 for a 4 cyl.