I sent my 1998 4 stroke 25 hp to a boat mechanic friend who thoroughly checked it out--it was cutting out terribly with a little throttle, but idles and runs great but only with a little throttle, more = cutting out. The last thing they did was clean the carb (already had a new kit in it)-this motor , bought new by me, had less than 30 hrs on it when this first occurred 3 years ago after I cleaned the carb (sitting unused for a year w/gas in it). Got it back today, ran crappy, cleaned the carb again(didn't need it) , but looking in the manual, i remembered not seeing the "ball" -was missing from under the plunger/spring on the bowl bottom--could this missing ball cause excessivily rich fuel (some slight blackish smoke when cutting out). My friend claims he ran 2 stroke mixed gas through it, it was fine, checked compression, plugs, gas lines, all else, he's perplexed and so am I.Could this missing ball be the problem?
