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  1. #1

    Default wiring diagrams for yamaha 250 saltwater 1999

    Im replacing my 1985 200 hp Yamaha on my grady white with a 1999 Yamaha 250 hp saltwater , Could anyone help me with input on this and does anyone have
    any wiring diagrams. Also do I use the primer ball from my old fuel line on this injected motor? I have 5/16 fuel line now do I nees 3/8 line.I have a new dig.
    tac. will it hook up to my wiring.

    Thanks ,Scott

  2. #2
    Captain JUSTINTIME's Avatar
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    Talking Re: wiring diagrams for yamaha 250 saltwater 1999


  3. #3
    Petty Officer 1st Class
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    Default Re: wiring diagrams for yamaha 250 saltwater 1999

    Yes, you should be using 3/8" all the way, be sure to change fittings also...any Yamaha digital tach will work except of coarse for Command Link....Justintime gave you all you need to wire anything, just be sure to check and clean ALL the grounds from motor, very important on Yamahas....

  4. #4
    Supreme Mariner
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    Default Re: wiring diagrams for yamaha 250 saltwater 1999

    if you wish to use your original guages you willhave to buy some adapters as the trim,oil and oil alarm harness on the engines went from round to square in 95.
    the 10 pin main harness is still the same.
    in 99 the 250 should have still had the 3 wire trim sender, if its a two wire you willhave to have a new trim guage or tach if you wish to have a trim meter.
    5/16ths line is sufficeint but I would rather see 3/8ths.
    best thing is to elimiate the check valve between the engine mounted filter and the pumps. install a vacum guage with some T fittings between the filter and the lower pump intake , fuel system vacum must be lower than 6"Hg at wot.
    the factory fuel line is about 8mm

  5. #5
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    Exclamation Re: wiring diagrams for yamaha 250 saltwater 1999

    Does anyone know the part numbers for the adaptors that go from the round (old) at the engine to the square (new) at the engine? The new harness is in much worse shape than my 1991 harness. Also can I just match up each wire and splice them onto the old harness? That would allow me to sell the new harness with old connectors with my old 1991 225? If so where can I get diagrams for each? Thanks

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