So I bought a bass boat with a 1990 Johnson 90 that’s got a downed cylinder and detonation on the other 3 cylinders. I also have a 1979 evinrude 115 that’s not locked up but lacks spark on 3 cylinders. Local boat shop told me to swap all the electrical and powerhead to the lower cowling from the 90. My question here is are the power heads the same to a T? I know the ignition systems a little different but I don’t wanna go and tear both powerheads apart for this to go sideways. He basically told me to take every bit of wiring off both and use the ones from the 1990 model on the 1979 model. I would just like y’all’s opinions on this.
