Nissan 25 HP Problems

[Murphster05]

Hi all. Have a Nissan NSF25A from 2001. Just got it a week ago. Motor has been stored and sitting for a while now, changed the fuel filter, sprayed carb cleaner in it, and tested it out in the yard with a hose hooked to it, seems to sputter a little. Took it out to the lake, won't get up and go, stays really slow no matter where the throttle is. Took off the air box and twisted the throttle, only one jet is spraying fuel, but that is with the motor sitting and off. Don't know anything about carbed motors, and don't know where to get a repair manual. Hope to not spend $500 at a shop getting it looked at, so any help you can provide would be awesome.

Thanks!

 

[pvanv]

Re: Nissan 25 HP Problems

Difficult to diagnose from your description, however fuel seems likely.

Parts catalog available on TG's website at http://www.internetoutboards.com/PartsCatalogMenu.htm

Factory Service manual available from any Tohatsu/Nissan dealer.

Suggest you start by removing the carbs, disassembling them, soaking them in good carb cleaner, and reassembling them, replacing parts from a carb kit as needed. All 3 carbs must be working properly, or you run the risk of having one cylinder too lean -- resulting in pricey repairs.

Other PM items would be oil, filter, and LU lube change; Water pump kit, etc.

 

[Murphster05]

Re: Nissan 25 HP Problems

Took the fuel lines out and a few other small items, but the triple carb is quite confusing looking, very intimidating. Not sure how comfortable we are delving into the motor, and another huge problem is how to see if it is running better once we have soaked some of the items in carb cleaner. Out of the water it always sounds like it is running well, not comfortable putting it in gear out of water, is there some way to see if we improved anything?

 

[pvanv]

Re: Nissan 25 HP Problems

The 3 carbs need to stay synchronized. Aside from that, they are just like any 3 individual carbs for 3 smaller motors. Cleaning and adjusting will be detailed in the Factory service manual. I don't recommend the aftermarket doorstop manuals for these motors.

You can't safely run above idle out of the water, even with muffs on. You need a test tank or a barrel-of-water setup at a minimum. Better yet is to do final in-gear testing on the boat in the water.

We haven't completed any real diagnosis yet. Have to hit the basics first -- (spotlessly clean fuel system, 100% firing ignition with new plugs, etc.), and then you may find that all is well. If not, then further troubleshooting can proceed.

If the work seems too intimidating, you may be better off having a Tohatsu/Nissan mechanic do the work. Just please don't tear everything apart, get scared, and then haul a bushel basket of bits into the shop. We frown on that in our shop.

 

[TOHATSU GURU]

Re: Nissan 25 HP Problems

"We frown on that in our shop"

We scowl at ours...You must be nicer