Re: 1984 Mercury 9.8 Impeller in still not pumping water
Impellers don't have break in periods nor do they spin freely. As said above, they are key'd to the drive shaft so they spin with it. They don't need a break but you can install one wrong by rotating the pump cover clockwise or the drive shaft counter clockwise when you're trying to get the cover to go over the impellor. If that happened you would get some water flow but your new impeller would probably fail quickly. The correct method is to lubricate the inside of the pump cover and while holding it straight, apply moderate down pressure while rotating the drive shaft in a clockwise direction.
Your method of checking for blockages is flawed. Your old impeller destroyed itself and there could be chunks at the thermostat, the popet valve or even stuck in the water tube that will not effect the flow of air when you blow into the tell tale tube.
Pull the lower unit off again, pull out the thermostat and the popet valve and blow air in from the water tube in the bottom of the mid section. If you can't get airflow then straighten out a coat hanger and see if you can't dislodge what ever it is thats blocking.
Do not remove that water tube, odds are you will never get the grommet back in correctly. If the blockage cannot be cleared you'll need to pull the powerhead. On a 9.9 you're looking at a day to pull it, clear it and put it back together. Count on around 2 weeks if you have to order gaskets, (and you should).
So the encouragement is that most of the time these blockages can be cleared.
