94 Nissan 8hp NS8B outboard advice on maintenance?

[Todd RT]

I have a Nissan 8hp NS8B I use on my inflatable. LOVE This motor!

I've had it about 2 years. Looked brand new when I purchased it. I have only done carb work on smaller outboards so looking for some advice on maintenance.

I have the service manual and have been reading it thoroughly. I have spoken to local Nissan Marine Service Centers also.

They basically advised changing the Plugs, Impeller, and checking the fuel system. They didn't recommend a thermostat change as you have to pull the head.


-I am changing the plugs this week, and inspecting the condition of the plugs for any signs of problems.
-I am changing the oil on the lower end.
-I am CONSIDERING changing the impeller, but the water flows well.
-I am going to get some of those Thermo-Sticks (wax sticks) to verify that the motor is not going over 194F after running her hard.
-I now use ethanol free fuel and a 50:1 ratio

My main questions are:

-Should I change the impeller even if she's not getting hot?
-Is it normal for water to come out of the "pee hole" and also the back idle-vent? The water is quite warm out of the back idle-vent and coming out of the prop.
-I assume the thermostat is working as the water doesn't start flowing out of the back idle-vent until she warms up. But instantly comes out of the "pee hole"
-On this small of an outboard, should I replace the prop if it's a little beat up? Or can it be reconditioned? Or is it not a big deal on such a small motor?

Thanks for all your advice. I look forward to reading your responses!

 

[RogersJetboat454]

Re: 94 Nissan 8hp NS8B outboard advice on maintenance?

-Should I change the impeller even if she's not getting hot?

Yes! It's cheaper to replace an impeller as preventative maintenance then to replace an impeller and a power head after an unexpected melt-down.

-Is it normal for water to come out of the "pee hole" and also the back idle-vent? The water is quite warm out of the back idle-vent and coming out of the prop.
-I assume the thermostat is working as the water doesn't start flowing out of the back idle-vent until she warms up. But instantly comes out of the "pee hole"

All sounds normal to me, although one of the Nissan/Tohatsu Guru's may have a different opinion....

-On this small of an outboard, should I replace the prop if it's a little beat up? Or can it be reconditioned? Or is it not a big deal on such a small motor?

Well, it all relative to what your definition of "a little beat up is". If the prop has a couple of small nicks that may be easily dressed with light filing, I would run it. If it has gouges, or chips then consider having it rebuild or replaced. Keep in mind a prop with missing or damaged material may be causing undo vibration which could have an effect on the life of your lower unit. Price of rebuilding VS replacing all depends on the cost of a new prop vs the cost of repairing your prop. A prop that truly has minor damage may be half as much as a new one to repair. On the other hand if a replacement prop is fairly cheap, it may be wise to buy one, and use your old one as an emergency spare.

 

[Sea Rider]

Re: 94 Nissan 8hp NS8B outboard advice on maintenance?

Tohatsu parts outlasts what service manual intervals recommends, if boating frequently all year long, probably not your case, there's a main maintenance at 300 hours. Some people change parts each year or each 2 summers as piece of mind...

If you flush your engine after each use, related water parts as impeller, thermostat, head gasket will have a long life. Check your service manual and the service intarvals parts change recommended for your engine model. If parts like plugs, impellers, are changed by hours use for best performance, would be a cheap investiment to buy a tiny tach, hardline tach and check/change by running hours.

Happy Boating

 

[RogersJetboat454]

Re: 94 Nissan 8hp NS8B outboard advice on maintenance?

Tohatsu parts outlasts what service manual intervals recommends, if boating frequently all year long, probably not your case, there's a main maintenance at 300 hours. Some people change parts each year or each 2 summers as piece of mind...

If you flush your engine after each use, related water parts as impeller, thermostat, head gasket will have a long life. Check your service manual and the service intarvals parts change recommended for your engine model. If parts like plugs, impellers, are changed by hours use for best performance, would be a cheap investiment to buy a tiny tach, hardline tach and check by running hours.

Happy Boating

Don't mean to be contradictory, because obviously following the manufacturers guidelines on service part replacement is the best thing you can do, but in this posters case, who's to say how recently the impeller has been changed? The OP has had this 17 year old engine for only 2 years now, and made no mention of a recent impeller replacement. There's no telling how recently this motors previous owner replaced the impeller (unless the OP has a receipt from the PO for its replacement), so personally I would be putting a new one in for piece of mind.

 

[pvanv]

Re: 94 Nissan 8hp NS8B outboard advice on maintenance?

Don't mean to be contradictory, because obviously following the manufacturers guidelines on service part replacement is the best thing you can do, but in this posters case, who's to say how recently the impeller has been changed? The OP has had this 17 year old engine for only 2 years now, and made no mention of a recent impeller replacement. There's no telling how recently this motors previous owner replaced the impeller (unless the OP has a receipt from the PO for its replacement), so personally I would be putting a new one in for piece of mind.

Absolutely agree. Also, I would always recommend the full WP kit as opposed to just the impeller.

BTW, in our shop, we use the cheap, home-depot-type, general-brand gun-style infrared thermometer as opposed to wax sticks. Tells temp at any location instantly, and rapidly pays for itself, since sticks are a one-time use, and the IR gun lasts and lasts.

 

[Sea Rider]

Re: 94 Nissan 8hp NS8B outboard advice on maintenance?

If you don't know what previous owner has done/changed on that engine, definitely place a new water pump kit for your peace of mind, of course with previous LU down to check the condition of the actual WP kit, if in good condition you could use it a bit longer...

Happy Boating

 

[Todd RT]

Re: 94 Nissan 8hp NS8B outboard advice on maintenance?

Thanks everyone. I took your advice, called a local Nissan Marine Dealer to order parts... Was about to order plugs, fuel filter, Impeller Kit, lower end oil, etc. But for $159 they are going to do all those changes and inspect everything from top to bottom.

Considering the age of the motor... it's best to do all this preventative maintenance.

Thanks for pointing me in the right direction!