It should start within a few seconds of starting the motor. If you're running it in a barrel be sure it's in deep enough so the water pump gets primed.
Repairing the water pump on those is pretty easy. Check that the pump and water tube don't have anything blocking them; it's common for the little rubber fins on the impeller to break off and plug things up.
tomhath: Good comment. I had a small piece of rubber break off and land up in the jacket of the power head of my 84 Johnson 7.5. It acted like a pinball in a pinball machine. The motor would run great and than all of a sudden it would overheat and steam. I'd stop and re-start and be good for a while and the whole process would repeat itself. Found the small piece of rubber would bounce around and eventually block the discharge hole inside the head and not allow a flow. Found it after removing the side plate on the block. Something you'd not expect to ever happen.
I once found such a piece UNDER the water pump on my 50 merc 1967 ...the piece was floating up and down between the water intake slots and the pump body....grrrrrr! :-(
Thanks for all the good help! I ordered a new impeller which I should install anyway but in the meantime I took TomHath, et al advice and put a small piece of braided wire up the discharge tube a bit. And instead of a light drip I had previously gotten an nice stream flowed! I never would have thought of such a thing had it not been for the generous help on this forum! You guys rock!
make sure to read leeroys ramblings, it the best resource you will have , short of a proper service manual . ( and better in some aspects as his articles discuss things not mentioned in any manual!)
