Re: Nissan 3.5B - How do I change the impeller?
TG Elvin is 100% correct. The manual is the way to go. I have a few observations here, as I have done work on dozens of these bulletproof 3.5 2-strokes:
First, if the impeller has flipped blades, odds are that someone turned the prop (by hand) the wrong way, with the motor in gear. That's never good, as once the impeller gets old, the vanes will get stiff and break off when flipped backwards. They will then plug the water passages. I have seen broken-off impeller blades in the intake strainer, and jammed in the water tube, causing the water flow to be severely restricted, and the powerhead to overheat. However, assuming the impeller is still fairly supple, just running the motor should flip them back to the correct direction.
Second, there is a "Water Plug" (reference number 6-25 in the parts manual) screwed into the underside of the driveshaft housing. It's a short hex head cap screw, 10mm head, with a gasket under the head of the bolt. This will allow access to the water in the jacket. So if you feel the telltale may be plugged, you can unscrew this plug to observe whether the water jacket is pressurized with water. If the telltale tube has gotten clogged, you can use a stiff wire to push the debris back through the telltale. Then, with the water plug still removed, the debris can be purged through the bolt hole when the motor runs, and the water circulates. Reinstall the bolt, or there will not be enough water pressure to cool the powerhead.
Third, you can buy just the impeller (369-65021-1), from any Tohatsu/Nissan dealer, for a lot less than the whole water pump kit, as long as the guide plate and cup haven't gotten too worn. The impeller is the cheap part -- the labor is the lion's share of the cost here. Whenever I have a 3.5 LU off (for any reason), if the motor has been in service for a season since last serviced, I always change the impeller. Cheap insurance, and factory recommended. New pump gaskets are always a good idea, BTW.
Long story short, the parts manual would have helped a lot. It's free to download at
http://internetoutboards.com/Parts ...2.5A2-3.5A2-3.5B2 (2003) - (002N21040-4).pdf. And the service manual is available from any Nissan/Tohatsu dealer.
