18 h.p. Evinrude (18903D-E02708) 1969
Following a complete tune up I barrel tested my motor. starting & running was flawless. Headed to the lake fired it up and dialed in the rich/lean. Started out slowly increasing the speed. I could tell it was rich and it burned off shortly and ran smoother. Got the boat on plane and ran perfect. kept it there for several minutes as I went around the lake. Finally I pinned it, and it ran perfect for about 30 seconds and fell on its face. I dumped the throttle and it caught and stayed at idle. I repeated several times & no change. I checked everything I was told to do with no success. Check the following...fuel can & lines...good pressure...new fuel pump...coils...points & condenser...carb rebuild & float check...The engine seems like it's always rich. Had a couple other carbs that fit. No change. the high speed nozzle seems really huge, but I'm assuming that's the way it's suppose to be. Sincerely stumped!