My 70 hp outboard runs fine at start up and trolling for a while. Then I shut it down and it won't start, only way to start it is remove cowel and manually move the throttle valve then it starts right up. By the way I'm hoping im saying the right thing(throttle valve). I'm thinking it is a choke problem but I'm a little confused here. My carb doesn't seem to have a choke, and there is no linkage connected to throttle valve, How does it work?