I have a 40 horse evinrude jet. Model E50JERE. It has always run great until the last time out. Currently, it starts great, and idles fine, but the motor won't break loose to accelerate. At times, it won't let the RPMs rise. When you give it more throttle it bucks and hesitates. Periodically it will run wonderfly, but most of the time it acted up on the last time out. It seems that if I let it sit for an hour it will run great as long as I dont let it idle at all, as soon as it idled it would go back to bucking with more throttle. It pumps water, so I dont think its overheating, and I used the same oil mixture as always. Any ideas? Thanks.