My 15 hp yamaha will not accelerate with the manual choke pushed all the way in. If I pull it out partially it runs fine and accelerates.If im running at high speed in gear I can pull the choke out to get fast speed. Seems like a mixture problem. The engine seems to run fine as long as I keep choke partially closed (lever partially out). Any ideas appreciated. Wondering if could have anything to do with primer bulb??
