1986 Mercury Marine Mercury Outboard 1135746 OIL INJECTION COMPONENTS Diagram and Parts
AFAIK the engine is passing a mechanical action from the engine to the pump rather than suction.
The amount will be very small though! Remember that it's 50:1 so for every 1ml of fuel pulled through you'd only pull through 20microlitres which is about 1 drop! You probably can't even get the tick over speed for more than a few seconds by hand - say thats 600rpm thats ~10 rps. Simply turning it by hand rather than trying to start it would be more like 1rps! At 600rpm a (modern) outboard your size would drink between 0.2 and 0.5gph - lets call that 2litres an hour. So if you turned it over at 600RPM for an hour you would expect to pull through 40ml of oil if the mix is right. But as I suspect you can't maintain that RPM so more like 4ml in an hour which means in 5 minutes you'd only pull through 0.2ml of oil. Thats not a lot!! Having the throttle open might help because you might make the oil delivery think that it was drinking 40-60litres an hour of fuel at 5500 rpm so 330,000 revs an hour. Thas 0.18ml per revolution, so 0.003ml of oil (less than a drop). If you could muster the energy to turn it over at WOT for 5 minutes you'd maybe pull through a ml of oil?
Get what I'm saying - not big volumes and manually turning it over might not bring much through...
IF you ran the engine on 50:1 from the tank with the oil pump output disconnected from the fuel and dripping into a suitable dish. You'd need to seal off the pipe or you will get air in the fuel. You'd then be able to pull it up to real revs?
But do you think the pump is not pumping or just that the nipple to attach the pipe to is broken?