I may be wrong , but I have to disagree with the other comments about the rev limit alarm. I have a Suzuki 25 fourstroke and in my owners manual it said that when it hits the rev limit red light comes on and it pretty much cuts power to the moter. You have to let completely off gas for a few seconds before it will reset. My moter has done this ever since the day it came ou the crate . I changed my prop and it helped somewhat , but I'd like to know what they tell you at the dealership . I have read online about this happening to a few people.
dont think its your rev limit alarm. sounds like your overheating, or your oil pump could be going out. an over rev limiter will just cut the fire intermittently and hold you at the correct rpm, it will not shut it down.