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  1. #1

    Flow Control Valve for 4 Stroke?

    Are these typically reserved for 2 strokes or can they also be installed on 4 stroke skis?

    The STX-15f is probably already is equipped with a system to modulate water flow to the exhaust so this likely does not apply. I still feel like my water box gets filled up easily and bogs down at low RPM. The exhaust note changes after a few seconds of extended RPM operation as it cleans the waterbox out. Its only after I've reached cruising speed (~35mph/5000rpm).

    I haven't really inspected the cooling system on my '15 STX-15F, but would there be an benefit to putting a flow control valve on a 4 stroke? Or would this be a disaster waiting to happen?

  2. #2
    Any ideas on this guys?

  3. #3

    Join Date
    May 2008
    I think this mod (Also known as the Ferco mod for the Yamaha 1200/1300 motors--RIP Ferco---) was more relevant to the 2 stroke engines which made their power in the higher RPM ranges. With all the torque coming from a 4 Stroke on the lower RPMs I am not sure it would help much. Also, where you would have to install the valve on a Kawasaki, there are other hoses that inject water from other parts of the engine, so it would be tricky. The Yamaha mod only involved the 1 hose so it was easier to direct the water how and where you wanted it. If any gains were to be made, I'd suspect it would be negligible and I'd also feel uncomfortable about messing with the water coming from the hot parts of the motor.. Just my 2 cents..

  4. #4
    Heres a picture of the STX waterbox. There are 2 hoses that look like they inject water into the waterbox entrance. At least one of these could be flow-controlled to limit idle/low rpm water injection. Just my thoughts.

    Click image for larger version. 

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