Nissan NSF5A carb question

[Bullie]

I picked up a 5 hp Nissan 4 stroke some time back and have just now had time to take a look at it. All I know from the PO is that it doesn't run. My gauge will not fit the plug hole so I haven't checked compression but it has excellent spark jumping 7/16 with a bright blue snap. I removed the carb to clean and found this.



The PO has buggered up the main jet pretty bad. I figured I would look for some advice before trying to remove it. Any ideas on how to remove it without making the situation worse?

Another question, my first time in one of these carbs, is that the original pin for the float? I tried to tap it out to take a look at the needle but it didn't budge so again I thought I would seek a little advice. It definitely didn't just push out like I am used to.

 

[pvanv]

Forget it. That ethanol/water corrosion will never be cleaned by ordinary means. get

3R4032001M

CARBURETOR ASSY, MFS/NSF6A2

$122.35

and end up with a 6 hp motor.

 

[Bullie]

I was afraid that's what I would be told. I looked up carburetors for it last night kinda trying to prep my mind and pocketbook. So, the only difference in the 5 and 6 hp is the carb?

 

[isaksp00]

Looks like the PO was not in the habit of running it dry after each use.

 

[Sea Rider]

Have seen carbs in much worst conditions than yours which looks near mint, check this one, was put back to work with same original internal parts after a patient part removal and meticulous cleaning.



Corrosion is usually an internal aesthetic issue, as long air & fuel passages are not compromised carb will work nicely again. Run bowl dry if engine will be stored sitting for long time periods. It's entirely up to you if wanting swapping carb or repair the current carb. To pull out the broken jet and float pin will need to take carb to a machine shop and have both professionally removed if happen to be seized and if isn't a costly operation. If costly, buy a new 6 HP carb as suggested.

Happy Boating

 

[Bullie]

I ordered a 6 hp carb for it. Running like a new one now.

 

[mrashenden]

I subscribed to this post because I have a NSF5A (5hp 4 stroke Nissan) and over the past 6 months I have been trying to fix an idle/stalling problem. It started fine but would never settle down to a low enough RPM without stalling. Over the winter I cleaned out the carb using spray carb cleaner and a rebuild kit. Expecting that this solved the problem, a month ago I inflated the dingy and dropped the motor on it for a test only to find that the exact same thing was wrong. With frustration I Googled and read anything I could find on sputtering NSF5As. I found advise that noted overfilling the oil could cause this - and it was notably overfilled (previous owner). With this resolved, I again optimistically inflated the dingy and dropped the motor on for a test... Could this have been the problem all along??? It was not.

Back to the workbench...

I decided I would reclean the carb but this time, despite it having plastic parts and against the advise of many, I thought I would dunk it in a gallon of Gunk Parts Cleaner for 4 hours. I figured if it melted the plastic parts, I would buy the 6 hp carb as was suggested above.

I took out the float, needle, low speed jet, high speed jet and related tube, and dunked the carb and jets (not the needle or float though) for 4 hours, then rinsed the dunked parts with spray carb cleaner in every nook and cranny, and lastly used pressure air to blow it all back out. In comparing some pics I took, the low speed jet definelty went in a bit further than the last time so something was stopping it before - that probalby was my problem. I also adjusted the float so that it sat level (when holding it upside down).

But thankfully, this did the trick. Yeay!! Now my motor runs like it should. A nice, steady idle and smooth acceleration. My only regret is that I didn't get the extra HP that the new carb would have provided, but I saved $100+ so all in all fixing it was the right solution for me.

The morale of my story - Spray is not strong enough to get the stubborn crud out.

Thank you to those that provided the advise above. It really helped me decide that I could risk the dunk approach.

 

[Bullie]

Way to hang in there and work it out. I wish I could have done that. I wonder if you can even tell the difference in 1 horsepower in these motors?