Nissan/Tohatsu 6hp xl shaft impeller replacement

[oceanroadus]

Hi all, this is my next project as waterflow is less than I would expect and motor is new to me, 2007 model. Anyone have any tips on removing lower unit and installing impeller.  I have done this on marine generators in the past but not an outboard.  Thanks!

[marc]

The impeller kits come with a water pump guide plate. That's #17 in this diagram
http://www.boats.net/parts/search/Nissan/Outboard/2007/NSF6B/GEAR%20CASE%20(DRIVE%20SHAFT)/parts.html
Most times I don't bother installing it and just keep the old one in place since removing it can be a PITA. The one time I did take it off, I was somewhat unnerved since I was then looking into the gear case and I didn't expect to be there! Nothing to be afraid of though. Everything was simple to put back together - it's just that I didn't expect to be messing around with the gears. The only additional work required was settling on the right gasket cement to use at the top end of the gear case (used in conjunction with the pump guide plate gasket -  #18 in diagram) and changing/refilling the gear case oil.

[oceanroadus]

thanks for info, I did this today and got it back together, still just drips water though, I really expected it to stream out the discharge. The impeller is tiny but I expected more, it is a 2007 anyone have any advice based on flow for these.  I have impeller fins going in the right direction I am pretty sure and feel mild suction at the water intake just above prop while in neutral, haha don't want to test that in gear!   

[marc]

I had a blockage where the water streams out. Used a paper clip to break apart some salt/mineral buildup I had there and that fixed my slow drip problem into a full fledged stream. (Yea. I'm talking about my outboard.) If I recall  correctly, on my Nissan I was able to unscrew the fitting where the water pisses out and was able to also examine  the outlet of the tube that the cooling water exits from to make sure that was free of obstructions.
Hope this helps.
Marc

[ghsfusioneer]

I'm not familiar with the details of the Tohatsu, but have experienced (and fixed) pump and cooling flow issues on my 4 hp Yamaha 4-stroke.  When I took the lower unit off to replace the water pump impellor, the brass water riser tube dropped out with the lower unit (when this happens you know you are in trouble). Turned out the riser tube was brass and had corroded to the point of failure right beneath the power head.  I guess the salt water inside and the corrosive exhaust gasses outside did it in and it is known brass and aluminum are opposites on the galvanic scale.  I  separated the power head from the upper casing to replace the tube.  This was more than just a minor repair.  So, in your case, if the water riser tube is leaking inside the upper casing (I would guess Tohatsu has one), you would see little water from the telltale hole.  Might be worth checking out.  Good luck.
Fusioneer

[oceanroadus]

I poked a straw from a can of WD-40 up the little pin hole in the discharge below the head and flow came streaming out, probably a bit of salt/mineral build up in the tiny hole.  Pumping nicely now, thanks for tips all!

[Salty19]

I use weedwacker line to clean the pee hole.  It;s strong enough to penetrate gunk but still flexible to get around corners.  I don't know if it's grunge in the lake or bugs making a home in there, but it seems like at least once a season I need to unplug that hole.  Stow a piece aboard in the toolbox!