Is there anyone who knows why my 1985 VRO 90 HP outboard loses power when I am at full Throttle. Here the thing...I pre mix my oil/gas 50:1 and using the vro pump as a stand alone pump. When I am up on plane my motor is like going to lose power and then pick it up again. This happens often. When I push the choke in from the key ignitons then the motor is humming with no problem...when i release the push in choke then it does it again. Does anyone know that the problem and how to fix it. Thanks