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  1. #1

    Default Yamaha 115ETLH 115HP 2 stroke Reed Valves/air mixture screws


    Need some advice and possibly if anyone else has a similar motor with a PDF manual that would be greatly appreciated.

    Reed Valves and air/fuel mixture screws

    Bought the boat 2 years ago. I have pulled the carburetors, cleaned them, applied new air/fuel mixture springs to hold the screws firmly in place (Didn't seem neccessary once I felt the tension old ones provided, but did anyhow). Would some composite reed valves really give me a smoother idle, as the motor currently seems to run a "little" off on the idle, provided i'm not sure i have the air/mixture screws set properly and/or the ignition timing 100% per factory specs at full retard (Hence the request for someone with a manual). I have this link : https://www.ptkba.com/wp-content/upl...E115A%20SM.pdf which provides a VERY close relation to my motor, BUT is not exactly specs for it so i'm left guessing the turns on the air/fuel mixture and the number of degrees to set the full retard/advance for the timing. It doesn't seem to make a huge difference 1 degree either side of retard but I left advanced alone due to most forums mentioning you can blow motor.

    So my topics is a little jumbled but guess what i'm asking is for some feedback if anyone cares to tune in:

    • Anyone have a PDF manual for this engine?
    • Know how many turns out for out for pilot air/fuel mixture screws(3/8-7/8) or (1 - 1 1/2)?
    • Retard/advance values for this motor?

    Thanks for reading

  2. #2

    Default Re: Yamaha 115ETLH 115HP 2 stroke Reed Valves/air mixture screws

    Most manauls idle timing is +/- between 5-7 ATDC i normally find that between TDC and 5 ATDC it works better disconnect the butterfly linkages when you do the timing and use the throttle stop screw for your adjustments .You also need to get the rpm +/- 675 -725 using the stop screw at the bottom carb when the butterfly linkages are reconnected .Also watch the cam butterfly pick up . the WOT timing mark is on the bottom of the flywheel and should line up with the mark on your trigger arm .disconnect the butterfly linkage when you check the WOT timing 21 to 25 degrees use the WOT stop screw to adjust .Air screw 2 / 1/4 turns out. from a slightly seated position.
    Last edited by Tegweni; 07-02-2020 at 07:08 PM.

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