When I first start my 1984 50hp Evinrude with the fast idle lever up it races exactly like it does if I run it out of gasoline to store it. Choking it may help but sometimes not. Once I get it in gear and open the throttle it seems to run normally. When I come off of high speed to near idle it dies. Often it won't restart for awhile. The fuel lines are clear, the fuel pump and screen look ok, and sqeezing the fuel line bulb has no effect. At one point when I was working on it the other day it ran normally for several minutes with the fast idle lever up. It idled and restarted ok. Next time I started the motor it went back to racing and then dying out. What do I check next?