I have a 1989 bayliner Capri I\o with 85 hp force engine. The boat will backfire out of the exhaust when starting but seems to run and start fine when it warms up on the muffs. When I give it throttle it stutters a bit before it will rev up. When I'm on the lake it starts and runs fine until I put it in gear and hit the throttle. It just won't plane out and seems to have no power. Keep in mind this was the first time I took it out since winter. Last year it would at least plane out with some stuttering but this year she really won't pick up speed. There is spark and good compression. Wondering what could be the cause of it not revving up. Put sea foam threw before winterizing and just checked the screen from fuel tank. Any help would be great!! Thanks