Boat doesn’t idles smooth. Is my Timing off?

[FullSendMissles]

I have a 1990 4.3 OMC Cobra V6 that idles really rough and back fires and occasionally stalls. I was thinking it could be the timing but not sure. What should I do?

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Could be ignition, but sounds like a carb issue to me,....
What's it's service history,..??

 

[FullSendMissles]

I have discovered a new problem. The boat no longer starts in idle. It will only start if I put the throttle up around 3/4 of the way. Then if I try to put it in idle it stalls. I tried adjusting the carb but it didn’t fix the issue.

 

[Bondo]

Ayuh,..... Sounds like crud in the fuel system has gotten to the carb,.....

 

[FullSendMissles]

Maybe, but I cleaned the carb and replaced the fuel filter so I don’t see why that would happen.

 

[GA_Boater]

Maybe, but I cleaned the carb and replaced the fuel filter so I don’t see why that would happen.

How did you clean the carb?

 

[Scott Danforth]

Did you service the points?

How did you clean the carb?

 

[FullSendMissles]

I took the carb apart and sprayed carb cleaner through the fuel and airways. I haven’t done anything to the points.

 

[Lou C]

You need cleaning tools and compressed air to properly clean a carb. Just spraying or soaking in carb cleaner isn’t near enough.

 

[FullSendMissles]

Yea, I used compressed air after I sprayed carb cleaner. I think I will try getting a carb rebuild kit.

 

[Scott Danforth]

make sure every passage in the carb is clear with a fine wire or piece of fishing line

service your points, set dwell (with a meter) and then set timing

then adjust your idle speed

both these things effect your idle

 

[Lou C]

Is this a 2 bbl or 4 bbl, Rochester or Holley?
The points need regular maintenance, I usually replace mine every 4-5 seasons or when really pitted.