The Johnson brothers started in 1922.------So only the 1972 model year is 50th anniversary.------In 1972 motors were green.------Any pictures ?----And your math is somewhat puzzling.-----I heard 1922 to 1982 would be 60 years.------Perhaps the 72 plate was put on another motor ?
The color indicates a 1972 model.-----1982 was white as far as i know.-----But it looks like a mix of 2 HP and 4 HP parts for your market.----Carburetor does not look like a Johnson carburetor either.----Flywheel is totally different from a local ( on the shelf ) 4 HP flywheel.------Post a few more pictures including lower unit / gearcase.
It has the cracked ignition coils.----That is something that happens to each and every one of these OMC motors.----New ones are available everywhere.------It has a lower unit that was used on 2 HP models.-----That carburetor is one I have never seen before.
Those coils are no good.----You think you have spark but I say no.-----You have some / weak spark.----Use a test device and see if spark will jump a gap of 1/4" ( 6 mm ) or more.-----With gas in the cylinders ( pots ) it should bark / roar like a dog or a wild lion !!
Yea those coils need to be replaced!! Those are REAL cracks. It probably looks like the northern lights up underneath that flywheel when you pull the rope!!
