2004 yamaha 9.9 bogging down when increase throttle.

[WEM]

I have a 2004 yamaha 9.9 that has started to bog down when I add throttle to the motor. Changed the fuel line and fuel bulb and put new plugs in motor. Plugs looked black with soot and looked like motor may be running rich. Checked compression and both cylinders show 110 pressure.

 

[JY Marine]

Black sooty plugs and bogging when you open the throttle usually points to it running too rich or having a carb issue. Since both cylinders are 110 psi, compression sounds pretty even. I’d first check that the choke is fully off, then clean the carb properly, especially the main jet, pilot jet, and float needle/seat. Also check spark strength on both cylinders because weak ignition can show up under throttle.