The wee key just keeps the bearing housing from turning.----That key will fall out if and when you get the bearing housing moving.-----Corrosion product / nature have jammed it up !!!
Very hard / impossible to disable compression release on these !!!----A leak down test would be easy to do if you know how the compression release works.----Just have to rotate the crankshaft so valves are both closed !!
Most motors rev up in neutral.---Even running on 2 of 3 cylinders.-----Not a good test of anything.----Have carburetors been properly synchronized with vacuum gauges ?
The pumps operate with a PRESSURE pulse.-----A 2 nipple pump mounts directly over the pulse port !---All you need on those is a nipple ( pump cover ) for fuel in.----And 1 nipple for fuel out.----The 3 nipple pumps do not mount directly over the pulse port.----No such thing as 2 outputs on these...
When prop is off ,the motor behaves like it is in NEUTRAL even if it is in gear.----Sounds like motor is running on one cylinder,----Or blown head gasket.----Or shock absorber below water pump is binding.---All easy to check out in my opinion.
Inspect all wiring on this motor.----And test run with another tank and hose.------Test run with the timing light.-----In my opinion it should be easy to find the issue !!
Most outboards drain themselves.----If in normal running position .----If the passageways are not plugged by silt / seaweed.-----Make sure drain holes on gearcase are clear too.
