Next on the list of factors is pressure. When you increase the surrounding pressure, you can usually dissolve more gases in the liquid. Think about your soda can. It is able to keep the fizz inside, because the contents of the can are under higher pressure.
Assuming a prop, it depends on how you are propped but with a redline of 6000 rpm, most outboards perform best with a cruise in the 4000-4400 rpm range. If you want top fuel economy, get a floscan or such and see what is the most efficient for your engine and prop.
Best Answer: First, make sure which type of shift system your outboard is. This can be done by taking your outboard's serial number and model number on the transom plate to an OMC dealer or OMC service shop. If it is electric shift, then you need to get a different gear oil specified by OMC to use.Do NOT use regular lower unit gear oil on an electric shift outboard.If it is regular mechanical shift outboard, then fill will regular lower unit gear oil.f it is electric shift, then you need to get a different gear oil specified by OMC to use. Do NOT use regular lower unit gear oil on an electric shift outboard.