Re: looking to increase charging system on 1983 175 johnson
OMC made two versions of the 35 amp charging system. The early version, starting in 1984-1988 and the later version, starting in 1989 through 1991. To tell the engines apart visually: The early version ignition system had the dual power packs, the later system had the single. The two systems have different charging components which can't be mixed and matched. The magnetic timing rings on the flywheels are different between these two systems and they require different (matched) timer bases so that they will fire the plugs correctly. These flywheels are scarce, since they have been long since discontinued, so you will need to scrounge around for the used parts you need. To make sure they match, you might want to visit a marine salvage yard and buy a complete inigition system off an engine with a blown powerhead. The systems are the same between a 150S, 235S or 175S model in the same model year. The flywheels have been know to have the center magnetic timing rings move, thus get out of time, and the magnets have been known to fall off (come unglued). You'll want to double check your parts when purchasing them.
