carburator problem

[tadams55]

I have adjust my fuel mixture screw and when I start the engine it does not stay in place and vibrates out could the screw be worn do I need a new carburator

 

[tadams55]

the carburetor is on a 1998 Nissan outboard 25 hp. NS25C3. I have had it cleaned and installed new fuel and fuel lines as well as new primer bulb and this seems to be the last problem I have

 

[pvanv]

Odds are you are missing the spring (1-21 in the diagram) for the screw:

346032680M

SPRING B

$1.40

 

[tadams55]

spring is right where it is supposed to be seems like it doesn't have enough tension

 

[SOG3]

Stretch the spring just a tad .

 

[tadams55]

checked everything out, I had my brother come up and we looked at it, it seem to have had some trash or gunk behind the pilot screw that would not let it seat so the adjustment could not be completed properly. he cleaned all of this and we got it started and adjusted idle and fuel/air and it is running pretty good will take it out next Saturday and run it for a while. one point of interest I marker the crews with a permanent marker so I can check randomly to see that the pilot screw does not move.

 

[Sea Rider]

The pilot screw usually doesn't move a bit unless spring has lost its elasticity, the one that generally moves with time and vibration is the idle vertical screw. A brush of finger nail polish applied to the contour of screw, where screw tip exits under small base solves the isssue.

Happy Boating