Nissan little cooling water

[Jarod]

Hi There,

I have a little Nissan 3.5b for my dinghy and have noticed the water flow is quite low at the moment (very little water coming out of the outlet hose), I know that sometimes salt crystals will form in the outlet line is there anything else you guys would suggest I look out for on this motor. I have never had it apart.

thanks

 

[CaptnNero]

Impeller ?

Check the water pump impeller. The ones I've seen are made of rubber or nitrile. They need to be replaced periodically. I've heard of the passages getting blocked too. Someone else can probably tell you something else to flush it with to clean it out.

 

[Jarod]

I recently read the following excerpt online:

"These little 3.5 Nissan motors can provide good service if properly cared for. The three problem maintenance areas are:

Overheating, caused by not flushing the cooling system properly and storing unit horizontally. The water cooling jacket around the cylinder is unprotected aluminum and it will corrode, clogging the 'water chamber. The first indication that there is aluminum oxide building up in the cylinder head is low or no water from small water discharge line. "

MY QUESTION IS CAN THIS BE REPAIRED IF IT IS A CORRODED COOLING JACKET AND WHAT DO I NEED TO DO TO CHECK MY COOLING SYTEM OUT AS I DO NOT WANT TO RUN THE MOTOR AGAIN TILL I FIGURE OUT THE LOW FLOW ISSUE.

PS NOT SHOUTING JUST WANT MY MSG TO STAND OUT FROM THE EXCERPT.

THANKS JAROD

 

[tenders]

Once you have the thing apart to replace the impeller (which according to Occam's Razor is likely the solution to the problem), you'll be able to follow the water flow through the exhaust. If it needs reaming out due to corrosion you should be able to run some pipe cleaners, weak acid, or flexible files through it.

 

[rwthomas1]

I've never been inside a Nissan 3.5 but plenty of other OB's. Most of the time the waterjacket is fairly accessible by removing the cylinder head, etc. and scraping out the salt crystals/corrosion. This is easier than it sounds should the impeller not fix the issue. Running it in a freshwater for a while may help clear it out too. RT

 

[ted_reshetiloff]

Funny you guys are talking about this motor. I just had mine stolen this week from my stern pulpit with a lock... I found it very easy to change the impeller on this guy. Also I noticed that it rarely spit much water until it had run for a little while. Almost like it had a thermostat. I got mine off ebay cheap and it was a great motor. I flushed it with fresh water at the end of a weekend of use but it already had a bit of corrosion from before I owned it.

 

[Emerald]

OK,

I will preface this with I haven't tried it and it is something I just thought of sitting here, but I think it has potential. White Vinegar dissolves salt, calcium, lime deposits etc. (acetic acid). Why not try giving it a vinegar soak/flush as I think your aluminum will be OK with this exposure. Just for interest, here's a couple links on using Vinegar, the first talking about using it in the head:

http://www.boatus.com/boattech/casey/04.htm

and then a site with all sorts of good stuff about vinegar:

http://www.versatilevinegar.org/


just a thought


-David
Independence 31
Emerald

 

[Jarod]

Hey Ted

Could you be so kind as to give me the basic idea of what needs to be done to change the impeller....I am pretty decent with bike motors and the atomic in my e27 but would just like a bit of guidance to get me started as I have not done much to outboards other than routine leg maintenance and the motor is new to me.

thanks

 

[ted_reshetiloff]

Im trying to remember but I think it was as simple as pulling off the lower end somehow or maybe jus tthe prop and pluuling out the old impeller. Its been a little while but I seem to recall it being fairly obvious. Sorry I am not much help here.

 

[Ray Rhode]

If you have the 3.5 without the neutral, you remove the prop then remove the two screws behind the prop. Remove the cover plate and there is the impeller. If you have neutral it is a little harder as you have to remove the foot. You might try running it in a bucket with a mixture of Salt Away and water. Not sure what is in the Salt Away but when I got my 3.5 the P.O. had not flushed it regularly so I ran it in a bucket of the stuff and I could see the flow increase. It also needed a new impeller.

Ray Rhode
S/V Journey
E35-III, #189

 

[tenders]

PS, I'm pretty sure the outboard does have a little thermostat. I seem to remember replacing one on an old 6 horsepower Evinrude I rebuilt five or six years ago with the help of a much more mechanically-oriented friend. It's quite possible yours has one too and after a few minutes' running will start spitting the usual level of water. Could also take that much time for a hard impeller to warm up and get flexible too. But really, if you're getting any water out of it at all there's no harm in running it at least warm -- just not hot for a long period of time.