9.5 Johnson or Evinrude bogs down

[sambob]

My 9.5 hp motor starts and runs very good up to half throttle, then bogs down at high speed. What adjustments on the carburetor should I make? Its has a type III carburetor.

 

[ezeke]

Re: 9.5 Johnson or Evinrude bogs down

The high speed jet is fixed so you cannot adjust it. It lies in the bottom of the float bowl, so it is subject to fouling from anything that sinks, plus gel from old fuel mix.

The jet or orifice can be reached with the tube from a can of gumout. The jet lies directly behind and in line with the float bowl drain plug.

Facing the starboard side of the carburetor, you will also find a small hole just below and left of the choke bowl. That opening leads directly to the high speed jet, With the float bowl drain plug out, you can run carb cleaner back through it to the jet.

Also check your fuel pump screen for debris.

Make sure that you are not overheating, which would also stop the motor. This is a problem with the 9.5 that is usually caused by weak impellers in the water pump, but could be bad thermostats.

 

[JB]

Re: 9.5 Johnson or Evinrude bogs down

That engine is also notorious for leaky exhaust gaskets, filling the bonnet with exhaust and strangling it.

Try it with the bonnet off.

 

[Captain Jeff]

Re: 9.5 Johnson or Evinrude bogs down

Also, just a common sense thing, make sure the vent screw is open on your fuel tank and you aren't getting any vapor lock or anything.