Ok... short story long.. I've had a mariner 8hp since new in early 90s . My father bought it for my fishing boat when I was approx 10 yo . He has since passed the motor ended up with my uncle in Florida . My buddy was near my uncle in Florida so I had him grab my ole motor and bring it back to nj for me . My uncle says he always had it serviced and it ran like a champ for him . I get it home hook up tank as fuel and pull till my arm nearly fell off ... No start.. plugs were soaked I thought no spark checked it had spark on seems both cylinders. I used a inline spark checker got light on both . Finally after cleaning the plugs she fired up and idled ok . Took it to local reservoir started first pull . Idled fine but when I tried to throttle up it seemed to be half power . Then she quit I had to paddle back . Got it home hore down carb to find all black bits in the bowl and all through the otherwise spotless carb . I assumed that's what it was . Cleaned it got new lines figuring old ones were deteriorating new primer ball clean fuel filter . Started her up again and it was running lean . Back firing etc . So repeated the carb cleaning process only to find black bits again . Now I'm thinking it's stuff in the tank . Drain tank put a new in line fuel filter bypassing the stock one . Clean carb for 60th time still back firing won't start without shot of gumout. So I'm thinking still fuel delivery issue . I went to harbor freight bought a ultra sonic cleaner . Gave it a few cycles yesterday looked super clean reinstalled . Same thing only start on shot of gumout rough idle back firing etc . It would stay running though once it got going. I adjusted air fuel screw from 1 1/2 turns to 2 and it smoothed right out . idle was calm no back fire so I took it out last night and again started right up but half power at full throttle . So now I found where the black bits were coming from an old can I used to fill my outboard tank . The outboard tank is now cleaned fresh fuel new filter new hoses sonic cleaned the carb. Almost as frustrating as typing this whole speal on a cell phone . Any help would be much appreciated .. oh and by the way compression is 110 more or less on both cylinders . Thanks in advance .. Joe
