Tohatsu 9.9 Runs extremely rich at higher speed,but smooth as silk at idle or near

[verno]

Tohatsu M9.9C. starts instantly, idles super, but as throttle increases it gets really rich, (like extreme flooding) and bogs down and dies, much heavy blue smoke. But if I bring the throttle back closer to idle it will again smooth out and excess smoke goes away. both cylinders have constently steady spark through all RPM ranges. Great compression and spark at both plugs while cranking. I have removed and cleaned the carb to no avail, still the same symptons.

Is there a quirk in the carb or fuel pump that I didn't see? Perhaps higher speed ignition/timing issue?

 

[TOHATSU GURU]

Re: Tohatsu 9.9 Runs extremely rich at higher speed,but smooth as silk at idle or nea

On an old engine like this it is a little difficult to come up with a "right the first time" fix. Use your service manual and run the diagnostic checks on the ignition system. Then take a look at the compression of the engine. Last start over with carb. Carburetor cleaning is an art as well as a 1-2-3 procedure. It's likely you missed something in the cleaning process.