Nissan 3.5 hp running super rich

[fishon71]

1996 Little Nissan 3.5 (NS3.5A) motor was stuck (soft stuck) - got it unstuck, cleaned carb - she starts okay smokes like crazy and is running super rich. I tried changing setting on needle pin (all spots) and a different carb no change. Compression is 120 psi any ideas? Only thing I can think of is the reed valve is not closing all the way - will that cause this issue?

 

[Sea Rider]

Re: Nissan 3.5 hp running super rich

Is that a 2 or 4 strokes engine ? By the way, have you added 2 stroke's oil inside a 4 strokes tank ? If engine works ok at all speed settings, reed valves are ok.

Happy Boating

 

[fishon71]

Re: Nissan 3.5 hp running super rich

Is that a 2 or 4 strokes engine ? By the way, have you added 2 stroke's oil inside a 4 strokes tank ? If engine works ok at all speed settings, reed valves are ok.

Happy Boating

This is a two stroke ...................

 

[Sea Rider]

Re: Nissan 3.5 hp running super rich

If you are at the correcy gas/oil mix ratio, that is 50:1 should not smoke heavier as a train... Put back carb's needle pin at hole it was factory delivered. Clean spark plug if heavily oiled, check gap to be 1.0 mm tight. Reed valves has nothing to do for excesive smoking, on 2 strokes, oil ratio does. Try new fresh adequate gas/oil ratio. Let the audience know...

Happy Boating

 

[fishon71]

Re: Nissan 3.5 hp running super rich

Tried all the things you mentioned, I have worked on a bunch of these in the past and when I had these symptoms after cleaning the carb it was always the needle adjustment. Even a different carb does not help this one. This one will not idle, runs rough, smokes like crazy, does not have the crisp two stroke high end and the barrel is full of sooty water. Obviously getting too much fuel. Not much to these but I'm at a loss - at first I thought I needed to run out the mystery oil but that should not take more than 5-10 minutes at a good rpm

 

[fishon71]

Re: Nissan 3.5 hp running super rich

okay solved - as I was cooking my steak on the grill, I look down on the deck and see this little brass sleeve between the cracks - yes the part that goes inside the carb for the air mix fell out when cleaning. Put it in and she runs like a top - oh well learn something every day.

 

[Sea Rider]

Re: Nissan 3.5 hp running super rich

That steak has saved you, anyway, put back that needle where it was placed factory delivered to match EPA regulations. No need to play with needle on that model, just idle speed. Asume you have found also the spring that rests against the slow stop screw upper body.

Happy Boating