Hello, I've recently purchased by first outboard motor for my first boat. After running it id really like to make sure it is well taken care of and have a few questions. It is a 9.5hp Evinrude Serial # j01427 Model 9322B built in 1973. When i crank it up and put it on full throttle it speeds up and then speeds down on it's own. It does this every so often. Also when i have it on low idle it cuts off. My question is what is wrong with it and what would you suggest? Thanks.