impeller installation on 6hp Nissan

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imported_dave j

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Hello, I have a Nissan 6hp 4 stroke model number NSF6A2S. First time changing the water pump impeller. The one I am replacing lost all of the rubber splines and I'm not sure which way they should turn in the little stainless steel cup. Do I turn the shaft clockwise and let the splines follow in that way? Or counterclockwise? Help would be greatly appreciated. Regards, Dave J
 
Sea Rider

Sea Rider

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Re: impeller installation on 6hp Nissan

Just lube your impeller & cup with soappy water and while sitting cup on impelller top rotate shaft CW untill cup sits evenly on lower base. Don't forget to install impeller key on shaft or impeller won't pump a drop of water...

Happy Boating
 
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imported_dave j

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Re: impeller installation on 6hp Nissan

Sea Rider said:
Just lube your impeller & cup with soappy water and while sitting cup on impelller top rotate shaft CW untill cup sits evenly on lower base. Don't forget to install impeller key on shaft or impeller won't pump a drop of water...

Happy Boating
Click to expand...

Thank You, Just what I needed to know. Happy New Year!!
 
TOHATSU GURU

TOHATSU GURU

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Re: impeller installation on 6hp Nissan

You do not need to lube the impeller or the cup. It goes in dry. It does not matter which way the impeller curls as it will correct itself when the engine is started.
 
pvanv

pvanv

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Re: impeller installation on 6hp Nissan

TOHATSU GURU said:
You do not need to lube the impeller or the cup. It goes in dry. It does not matter which way the impeller curls as it will correct itself when the engine is started.
Click to expand...

Yep. And NEVER use any grease or similar on the impeller. A little soapy water won't hurt, but remember: Anything you put on it may attack the rubber, and will be pumped through the cooling system (where you probably don't want it!) Also NEVER cycle or run the engine without water. Not even a second or two. Even pulling on the recoil without starting puts excessive wear on the wp if it's dry.
 
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imported_dave j

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Re: impeller installation on 6hp Nissan

pvanv said:
Yep. And NEVER use any grease or similar on the impeller. A little soapy water won't hurt, but remember: Anything you put on it may attack the rubber, and will be pumped through the cooling system (where you probably don't want it!) Also NEVER cycle or run the engine without water. Not even a second or two. Even pulling on the recoil without starting puts excessive wear on the wp if it's dry.
Click to expand...

Thank for all the good advice. Impeller all back together, hopefully I'll get the lower unit back in tonight so I can test her in the morning. Still having problems getting the drive shaft to push into the motor. Got the shifter in and the water pipe but somehow the shaft won't push in. Don't know if it has to be in neu. for. or rev.? I'm sure I will muttle through but I'm sure there is an easier way. Thanks again!!
 
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imported_dave j

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Re: impeller installation on 6hp Nissan

Thank You Tohatsu guro , but the drive shaft is the longest thing sticking out from the lower unit. It has no choice but to go in first. Problem is seems like something must have shifted as far as the thing the drive shaft goes into. The more I push and wiggle it around, it does not seem to find the opening (sound like Ive been there before!) lol.
 
Sea Rider

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Re: impeller installation on 6hp Nissan

If going by the service manual...

1-Lubricate the impeller blades with soapy water and slide upper pump case down driveshaft. Hold pump case securely and push downward while rotating driveshaft clockwise to seat the impeller..

2-Do not rotate driveshaft counterclockwise. Doing so will bend impeIIer blades in wrong direction and may weaken or damage the impeller.

The issue that grease destroys impeller is a mith, being a light coat, water driven by impeller shaft running at 3-4 K at wot will wash off this thin grease coat in seconds. Rubber impellers could have issues with grease, if kept sitting for long time after replacemment. Tohatsu elastomers made impellers are bullet proof.

To place back tail, apply a light grease coat on upper splinned shaft, align water tube, insert shaft upwards till stops, if lucky will slide in, if not, rotate a bit flywheel while pushing tail upwards, shaft should slide back in, align/secure shift rod in place, tight well all lower bolts and that's it..

Happy Boating
 
TOHATSU GURU

TOHATSU GURU

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Re: impeller installation on 6hp Nissan

Yes, some people do not read service manuals. Instead they write them.

The reason you don't use a lubricant on the impeller is due to the type of water pump being used. It has nothing to do with destroying an impeller. Also, bending the water pump impeller blades does not weaken or damage them. Seriously, you really should stick to something you know something about like pan flutes or mud huts.

Back to the drive shaft. You have to install the drive shaft correctly first. Then line up the water tube and shift rod. The crankshaft head case sticks down so far that if you miss install the drive shaft you cannot possibly line it up once the watertube is inserted.
 
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imported_dave j

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Re: impeller installation on 6hp Nissan

A slight differance of opinion about to grease or not to grease the impeller. I am quite sure the both of you are experts at this and sometimes have a differing opinion. I'm sure both of you have had many many sucessful impeller changes without mishap. I used my own logic with the impeller. I scuba dive and use silacone spray on all my rubber items. It keeps them from cracking/aging. Silacone in water soluble. I sprayed enough to make the impeller slippery. That was my disision based on all the input here. I also got my lower unit to accept the drive shaft (thank you sea rider). The thing I was missing was to turn the flywheel a little. Sometimes a little piece of advise makes the whole thing easy. Tomorrow is the test drive in the intracoastal waterway. With any luck I will get away from the boat slip!!. Happy New Year folks. I appreciate all of your responses. You made the whole project work for a rookie. Regards, Dave J.
 
tazrig

tazrig

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Re: impeller installation on 6hp Nissan

Dave, just a quick question... you said the impeller "lost all the rubber splines? Have you been able to account for them? I hope this didn't happen to you but sometimes when the impeller disintegrates the little pieces go up the water tube and get stuck in the cooling passages of your engine block. If you are still experiencing overheating after replacing the impeller you might want to start trying to hunt down those missing pieces. Hopefully you lucked out and they just passed right on through.
 
Sea Rider

Sea Rider

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Re: impeller installation on 6hp Nissan

Just my personal opinion regarding lubbing or not an impeller, if you are a experienced skilled mechanic definitely will sit impeller cup dry as you already know it will naturaly have some resistance due to splines being wider than cup diameter. A first time rookie doing the work will find that sitting an impeller dry into cup it's not as sitting a hat on his head. While assembling will encounter an impeller-cup resistance which he isn't familiar about.

Imported Dave's logics spraying silicone worked for him. Not only have sprayed silicone, but have used vaseline, cooking oil, love lub just to sit impeller cup faster and smoother. Try to sit a large HP impeller dry, it's like attempting dry sex, first time lube is highly advisable...

Happy Boating

BTW, Long ago have stopped blowing pan flutes, living in mud houses, witch doctor has been fired, now selling & servicing Tohatsu outboards just like you. What you have stated breaks completely your N? 1 Golden Zen Rule : 1) Look in your service manual first....
 
pvanv

pvanv

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Re: impeller installation on 6hp Nissan

But I enjoy pan flute music. Sometimes :)
 
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imported_dave j

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Re: impeller installation on 6hp Nissan

Tazrig, Thanks for the question. The impeller splines must have turned into a thousand pieces. I found them in the water intake, the ss cup and they were clogging up the pisser. I did my best getting them all out but who knows? I tested the motor in the intracostal yesterday. It is my secondary motor in case my Mercury 1968 35 hp goes down. Six horses is all I need to sputter back to the slip. But I ran the Nissan and ran it hard. I hope I cleared any remaining pieces of impeller. Motor was purring like a kitten and water was peeing with good pressure. I'll keep my fingers crossed but I think I'm OK for now. Dave J
 
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JOSEPHC

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Re: impeller installation on 6hp Nissan

TOHATSU GURU said:
Yes, some people do not read service manuals. Instead they write them.

The reason you don't use a lubricant on the impeller is due to the type of water pump being used. It has nothing to do with destroying an impeller. Also, bending the water pump impeller blades does not weaken or damage them. Seriously, you really should stick to something you know something about like pan flutes or mud huts.

Back to the drive shaft. You have to install the drive shaft correctly first. Then line up the water tube and shift rod. The crankshaft head case sticks down so far that if you miss install the drive shaft you cannot possibly line it up once the watertube is inserted.
Click to expand...

I installed a wp on my 6hp nissan last year.....got the wp from pvany and excellent instructions on how to install it...however, due to, I guess old age, I forgot to check one thing that haunted me the rest of the season....the following is what I did..
1. the wp is a tite fit in the housing, so I rotated the prop slightly as I pressed the housing over the splines...
2. there is a guide fixture halfway up the drive shaft that has a rubber bushing thru which the drive shaft must pass thru.I had to clean all the crud off the drive shaft and lubricate it so it easily passed thru this guide..
3. I was so focused on getting the drive shaft seated that I forgot to check if the water outlet tube was ligned up with the housing. After all was assembled, it dawned on me so the rest of the season I kept watching to see if I was getting sufficient water flow...it looks ok, but, there is that nagging doubt...so my advice is to take plenty of time when doing this...
 
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