"Richard, a 2 stroke outboard
"Richard, a 2 stroke outboard can run wide open almost forever, infact, prolonged idle or low rpm operation can kill them (or at least gum/plug them up bad).
They are designed to be run at wide-open-throttle (or at least in the range which will vary between 500-1000 rpms from max depending on the model).
At WOT they fire properly and burn up everything in the cylinder producing the least amount of build-up (carbon etc).
However, since 2 strokes are grossly ineffient, often sending a significant percentage of their fuel right out the exhaust port before it even fires, running them wide open really sucks up the gas.
Using the 10% rule of thumb, your 50 horse would burn about 5 gallons per hour at full throttle (or 20 bucks an hour at current gas prices).
Backing the throttle off to between 2/3's and 3/4's will cut that to less than half.
The "sweet spot" for any given motor is at the point where the timing is at max advance, but before the carb butterflies are fully open.
By operating the throttle with the hood off (and the motor off) you will see what I mean. As you increase the throttle, you will be able to observe the timing linkage advancing as well. It will stop at a point when you still have throttle left. If you had a tach you could determine the exact rpm (pretty much). On most 2 stroke outboards that rpm will be somewhere around the 4000 mark (give or take a couple of hundred).
Without a tach -- with a bit of practice and observation (and the help from a buddy to spot for you running with the hood off) you will be able to pretty much tune your ear to the sound of the motor when it reaches max timing. Once you have the "sound" pegged, you can usually find it....
Hope I made sense here
"