It is NOT optical ignition.-----Just the standard electronic magneto ignition that was developed / first used in 1971 models !!!----One coil with 2 sets of windings, one for each cylinder.----Run with L77JC4
Remove cables-----Shifter cable is the first one that moves.----Measure total travel of throttle cable from idle to full throttle..----Measure total travel needed on motor linkages from idle to full throttle.----Post what you find
Different paint color ?----Is it the correct cylinder head for that motor ??-----Drill a hole in the lower cowling and put a rubber bung in the hole after plug work.
This should be simple to set up.----Trip to a boat shop is in order.----Making a multitude of ---" lets try this "--- adjustments can lead to expensive repairs later.
The pay is not very good here.-----Sometimes the " fun grade " is important !----Finished a boat repair yesterday .----Owner brought case of liquid in cans as a huge token of appreciation.
Run with a timing light hooked up.----One cylinder at a time.----Might be able to spot if it is one cylinder or all that is missing.-----You did replace the wee rubber boots where plug wires screw into the distributor cap ?
There is a huge mis-understanding on carburetors.----It seems it is the first item that folks pick on to start trouble shooting.----And the carburetor upgrade theory will not go away.-----No wonder that fuel injection is so popular !
A 1979 would be white.----A 1979 has electronic ignition.------These motors were essentially the same year after year.----Great fishing motors and easy to maintain.----Check ignition coils.-----Check thermostat.