Nissan NS40C impeller replacement

[nakman8]

Just bought a Nissan NS40C 40 HP,approx. 1988. Started it for the first time using a barrel full of water. Concerned about water flow. Noting came out the "pee hole" but water did gurgle out the main outlets. Engine was running cool.tried cleaning peehole, still no water.<br />Should I be concerned? Will probablly remove lower unit and replace impeller just to be sure. <br />Could someone walk me thru the process please.<br />Do I split the housing just above the prop or at the top of the shaft just below the engine housing? I work on motorcycles and cars all the time,just not familiar with outboards. Thanks

 

[JB]

Re: Nissan NS40C impeller replacement

Ahoy, Nakman.<br /><br />Welcome to the board.<br /><br />You need a manual. You can find aftermarket manuals on this site. Go to the bottom of the page and click on Repair Manuals. <br /><br />If you prefer a specific factory manual, try the Tohatsu website.<br /><br />Good luck.

 

[SeaHorse]

Re: Nissan NS40C impeller replacement

Tricky part is taking the shift linkage apart. It's held together by two roll pins. Remove the top one after taping off the hole so it won't drop down the hole. Get the complete impeller kit which includes the stainless housing. Look at the parts explosion and get the orings, etc.<br />Pull apart the thermostat and check what you need there too.

 

[mbrueck]

Re: Nissan NS40C impeller replacement

If the Nissan was used in salt water, you may have to spend some time removing the lower unit. These were pretty typical of Japanese products of their time (excellent mechanics, terrible metallurgy). After disconnecting the shift rod and removing the lower unit bolts (I believe the 40 used bolts, as opposed to studs), if the lower unit won't drop down you may need to use a torch to heat the driveshaft housing while tapping the lower unit with a mallet to allow the lower unit to get loose.<br /><br />You'll also likely need new bolts for the water pump housing (make sure they're included in the kit). For a manual, you may need to go to a Nissan/Tohatsu dealer for your model. I have an '85 18HP Tohatsu and the only manual I could find was through the dealer (covers all Nissan/Tohatsu's 2.5 through 40).