10w30 in the summer is good, and if in cold climates then 5w30 will do just fine.
The 1985 Mercury Grand Marquis has a varying curb weight. It can be anywhere between 4,118 and 4,137 pounds depending on features.
Yes it will fit.
Look at the rear lower end of the engine
Anything's possible (...but why?)
The dry weight of a 1985 model, 25hp Mercury outboard is 105 lbs.
A person should know the firing order of their vehicle. The firing order of a 1985 Mercury Grand Marquis engine is 1-5-4-2-6-3-7-8.
The dry weight of an 1985 model, 75 hp Mercury outboard is 265 lbs.
.050
A grand marquis wiring diagram can be found in a Chiltons or Haynes auto repair manual.
The dry weight of a 1985 model, 40 hp Mercury outboard is 152 lbs.
Yes you can.
NO