Nissan NS5B Impeller Replacement

belizefishnchik

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Apr 18, 2011
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1999 2stroke. At mid to higher speeds, water ouput is good. At lower/idle speed, water output minimal to none. I plan to have impeller replaced (I purchased water pump repair kit (NissanOutboardParts)). I live in Belize with only "shade tree" mechanics available. I do not have a Service Manual - I do have Operators and Parts Manual.

What do I need to know to properly "stupidvise" the process ?

Anybody have a New/Used Service Manual available for purchase ?
 

TOHATSU GURU

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Jul 22, 2004
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Re: Nissan NS5B Impeller Replacement

Drop the lower unit, change the impeller, install the lower unit.
 

belizefishnchik

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Re: Nissan NS5B Impeller Replacement

I was hoping YOU would reply. Thank you.
I was hoping for alot of detail....
Before droping LU, what position does engine need to be in?
Does it need to be in F,N or R ?
OK, I guess the engine needs to be turned off........
Grease the impeller "arms" with marine hard grease "
Grease the rod/shaft the impellor installes on ?
Do I need to be mindfull of putting the LU back on the "exact" way/position it came off ?
Specified torq for LU bolts ?
 

pvanv

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Apr 20, 2008
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Re: Nissan NS5B Impeller Replacement

Yes, advisable to drop the LU with the motor off :)
Disconnect the shift coupler before unbolting the LU... accessible after you pull out the rubber grommet in the side of the exhaust housing leg. It will be clear what gear you want to be in to access the coupler. Typically Reverse. Use a 10mm socket to release the 6mm bolt of the brass coupler.
Same socket will fit the WP housing bolts.
Impeller can go in dry, or if you prefer, a little dish soap to help you spin it into the cup. OK to have a little grease on the driveshaft, but not necessary.
Requires a bit of a "feel" to realign the shift rod, drive shaft splines, and water tube (in that order). May take some patience, especially the first time.
The shift coupler then gets tightened where it was before. If you keep the shifter and the lower cam rod in position until reassembly, no adjustment will be needed... if not, push the lower rod down into reverse, verify the shifter is in reverse, and tighten the coupler in that position.
Verify correct range of the shifter.
 

TOHATSU GURU

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Re: Nissan NS5B Impeller Replacement

See service manual for service information. I will give you a tip though. Never, ever, put grease on the impeller on a Jap engine or a Chrysler/Force.
 

belizefishnchik

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Apr 18, 2011
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Re: Nissan NS5B Impeller Replacement

Paul,

Now that's the ewy-guuey detail I like............

I will also be checking/clearing the water intake "area". I have a flushing "contraption", but if something is stuck on the 'water channel", can I safely "ream" it out with a wire ? Any suggestions ?
 

pvanv

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Apr 20, 2008
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Re: Nissan NS5B Impeller Replacement

Whoa. The NS5B has the water inlet strainer on the underside of the antiventilation plate. What sort of "contraption" do you have? "ear muffs" will not work on this model. If the strainer is clogged, yes, you can clear it with a wire or similar. Same for the rest of the cooling system -- good to get salt/crud out of it while you have everything apart.

See if you can get a Factory service manual. It will be your friend.
 
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