Just above the gear box. The drive shaft from the engine to the gear box goes through it and drives the water pump too.
MQ11C = 1965 9.5 hp
50 to 1 seems to be ubiquitous for most 2 cycle engines of this era and later. I don't think you can go wrong with this mix, as I have been using it for many marine and other 2cycle engines for years.
A Johnson model FD-19D is a 1965 18 hp outboard.
1965
A 9.5 hp Johnson outboard, model MQ-11 is a 1965 year model.
1965 18 hp
Evinrude and Johnson outboards manufactured prior to 1965, require a 24:1 ratio. The JH20 is a 1965 model requiring a 50:1 ratio, this is roughly one pint of 2 cycle oil, to six gallons of fuel.
Kannard Johnson was born in 1965.
Rachel Johnson was born in 1965.
Wil Johnson was born in 1965.
Kirsten Johnson was born in 1965.
Darryl Johnson was born in 1965.