No dangers per se imo.What does Mercury recommend? I do believe there are only so many hours (esp WOT hours) in any engine, would not run any of my engines that hard.Back it down 500-1000 rpm get there 10 minutes later with a gallon or two fuel in reserve.
on my 115 evenrude the longest run at wot was 114 miles but when it got to 12 years old it needed a rebuild, now it is 21 years old and going strong. however the way it is proped it can run at wot and be 200 rpms below redline. my speedo says i usualy put 800 to 1000 miles a year on it
Filled the boat up this morning. I figure we went 80-90 miles. Took just less than 14 gallons.
We did the same distance today but the gauge shows fuller. Yesterday I did run WOT for about 10-15 minutes, other than that I was running 5000 rpm. Today was all 5000 rpm when running. That puts me right about 27 mph and seems like a good speed. I do miss how quiet the Crownline is, but this little 60 HP seems much more efficient. Guess you have to feed the horses.
If the engine turns 6,000 rpm you are more than likely slightly "Underpropped" which is a good thing, for your motor and its longevity. With the proper oil and good fuel most outboards are designed to run at high rpm's without problems. As some others have mentioned, I would also recommend pulling it back 10-15%, the time differential is not that much even if your going a long distance.
The factories "test" these motors at WOT until they break and then they pull them apart to find out what caused the failure. They rebuild and again, run them WOT till they break. This is a daily occurrence down here on Lake X, Mercury's test facility in Florida.