Re: 1950'ish johnson 5hp?
Oh-oh. I am pretty sure the TN-26 uses the highly obsolete 580040 ignition coils. They haven't been made in about 40 years and WILL be shot. Some people are fitting the next generation coils (available here at iboats) onto the old laminations.
The carb probably needs a new float and primer packings. The float is obsolete, but there is a Mercury float available here at iboats that can be modified to work. A fellow named Lloyd at the Antique Outboard Club (
www.aomci.org ) makes the packings. They are not expensive.
The water pump impeller is obsolete, but a 5.5hp impeller (available here at iboats) will fit if you ream out the center hole to fit the TN drive shaft.
Those are the motors that made Johnson famous for dependability, and there are still tons of them still running.