50 Hp nissan, possable water pump?

I have purchased a 1999 Nissan 50hp and have some questions, while running it in a 15 gallon tote bin it was not giving much of a tell tale and then a smoky tell tale. The 15 gallons of water were covering the cavitation plate by one inch about 2 inches above the inlet ports. I purchased a garbage can that will go deeper for the engine and will try that. I'm in Michigan and during the winter it's hard to use the earmuffs for cooling water. My questions are the following, was the water to low at one inch above the cavitation plate? When servicing the water pump is it a roll pin to seperate the shift linkage, can it be tapped out/in with no damage to its seal while pulling the lower unit? How much should I expect to pay for new impellar and related parts? Last question, where the block mates in the crankshaft area there is a gooy red sealer slightly protruding in spots, I've seen this used on transmissions cases before, does this mean the block has been worked on or is that a stock sealer? I just bought the outboard and hope it has not been worked on before. Lastly will these engines perform as good as the big three? Johnson/Mercury/Yamaha??

Water must be about 4 / 6" above the joint between the exhaust housing and the lower unit !-----------Running an impeller dry will quickly ruin it.--------Since you may not know the " history " on this motor I recommend installing a new impeller before using the motor.-It does sound like the motor was apart, sealer would be covered with paint if original from factory.

Year is irrelevant when servicing Tohatsu/Nissan outboards. Model/serial is everything. I'm assuming you have an NS50D2, right? An inch above the anti-ventilation plate is still below the water pump, so you probably ran the pump dry, destroying it. 15 gallons of water is not nearly enough for tank testing a 50. In fact, it would be marginal for testing a 3.5. You would need at least a 55-gallon drum, and have the water pump completely submerged when running. Even at that, bubbles from the exhaust can be drawn into the water intake, causing the pump to run "dry", so be very careful, and run only at low RPM with that kind of "shade tree" setup. The exhaust coming from the telltale confirms that you were not pumping water. Some motors (and about all of the current models) were assembled with red sealer; that's not a clue to condem the motor as having been repaired before.

Grab a Factory service manual Part# 003-21036-1 $45.00 and review it before getting into the work, and it will go a lot smoother.

The replacement wp kit for your motor is Part# 3C8873223M $57.93
The "factory" punch to drive out the stainless roll pin from the shift coupler is Part# 345722270M $14.97

No, disengaging the shift rod does not typically damage the cam rod bushing o-rings.
Never change just the impeller; always do the entire pump kit. Same labor, and a lot longer life from the job.

If you are unsure of the service history of the motor, or if you find any water in the LU lube, consider re-sealing the lower unit while everything is apart. For that, you will want 3C8873213M LOWER UNIT GASKET KIT $40.55

These items are available from any dealer, including me.

Paul and Racer One, Many thanks on your reply, I was hoping to hear back from you guys and I will definitley get the pump kit installed. Thanks for all the answers!!! Scott