Here's what Mercury Marine has to say on something built in the last 40 years.
Never start or run your outboard (even momentarily) without water circulating through all the cooling water intake holes in the gear case to prevent damage to the water pump (running dry) or overheating of the engine.
Pre-Starting Check List
Operator knows safe navigation, boating, and operating procedures.
An approved personal flotation device of suitable size for each person aboard and readily accessible (it is the law).
A ring type life buoy or buoyant cushion designed to be thrown to a person in the water.
Know your boats maximum load capacity. Look at the boat capacity plate.
Fuel supply OK.
Oil supply (oil injection) OK.
Arrange passengers and load in the boat so the weight is distributed evenly and everyone is seated in a proper seat.
Tell someone where you are going and when you expect to return.
It is illegal to operate a boat while under the influence of alcohol or drugs.
Know the waters and area you will be boating; tides, currents, sand bars, rocks, and other hazards.
Make inspection checks listed in the Inspection and Maintenance Schedule. Refer to Maintenance Section of your engines Owners Manual. If you don't have one, you can try this link with your serial number:
www.mercurymarine.com
Ready? Here we go.
1 Lower the outboard to the run position. Make sure all the cooling water intake holes are submerged.
2 Open fuel tank vent screw (in filler cap) on manual venting type fuel tanks.
3 Squeeze the fuel line primer bulb several times until it feels firm.
4 Set the lanyard stop switch to RUN position. Read the Lanyard Stop Switch safety explanation and Warning in the General Information Section.
5 Shift outboard to neutral (N) position.
6 Starting Procedure:
MODELS WITH ELECTRONIC FUEL INJECTION (EFI)
NOTE: Do not advance the fast idle lever (a) or throttle only feature
(b) for starting. The electronic starting system will automatically prime (choke) the engine and increase idle speed for starting.
Turn ignition key to the START position. If engine fails to start in ten seconds, return key to “ON” position, wait 30 seconds and try again.
MODELS WITH CARBURETORS
If engine is cold, advance the fast idle speed lever (a) or throttle only feature (b) to an approximate halfway (1/2) setting (note that some engines will need up to 3/4). Turn ignition key to the ON position. If engine is cold, push in on the key and hold in for 6 seconds to prime the engine before cranking. Turn the key to START position (note that sometimes holding the key in while cranking will help) and start the engine. If engine fails to start in ten seconds, wait 30 seconds and try again. If engine begins to stall, reprime (push key in). Immediately start to reduce engine speed after engine starts.
After starting, keep engine speed below 2500 RPM to prevent engine over-speed.
NOTE: Starting Flooded Engine: – Advance the fast idle speed lever or throttle only feature to the full maximum position. Without activating primer, crank engine for 10 seconds. Wait 30 seconds and repeat until engine starts. Immediately start to reduce engine speed after engine starts.
