1984 35 Hp. Evinrude lost 1000 Rpm

[JABIII]

All of the sudden my 84 Evinrude E35ELCRR is running about 1000 RPM or 10 MPH slower than it did. It starts fine and idles and runs smooth, it just runs slow. I have checked the throttle plate and it is fully open. Plugs are new but I pulled and replaced each plug wire one at a time and it slowed down but kept running, so I ***ume both cylinders are firing. In 25 years it has only fowled the plugs one time, and that was my fault. After cleaning the fuel pump (Which wasn't dirty when I opened it.) I pulled the fuel line off and removed the plug wires. Then I cranked the engine 30 seconds, it pumped 4.5Oz which I think is enough fuel???

I don't know what to do next.

Please help!!!!!
Thanks