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  1. #1
    Join Date
    Dec 2008
    Location
    Baltimore, MD
    Posts
    21

    Default "I have a pair of 671 TIBs in

    "I have a pair of 671 TIBs in a 44' Ocean Sportfish. They idle at 650 rpms, but this seems slightly high. Any insight would be appreciated."

  2. #2
    Join Date
    Oct 2008
    Location
    Oceanside, California, USA
    Posts
    3

    Default "We have the same engines in o

    "We have the same engines in our uniflite and they idle at about 650 seems high, but when we lower it the engine coughs alot and starts real slow!"

  3. #3
    Join Date
    Dec 2008
    Location
    Baltimore, MD
    Posts
    21

    Default Thanks Todd...I have not tried

    Thanks Todd...I have not tried lowering the idle yet to see the result. I have 1.5:1 Capital gears so I guess they can handle the torque at 650 rpms..will probably have my Detroit mechanic on board soon anyway

  4. #4

    Default Re: Thanks Todd...I have not tried

    Quote Originally Posted by maverick44 View Post
    Thanks Todd...I have not tried lowering the idle yet to see the result. I have 1.5:1 Capital gears so I guess they can handle the torque at 650 rpms..will probably have my Detroit mechanic on board soon anyway
    I have similar issue. The tags on my governors on my 6-71 Detroit engines say that the idle speed is between 500-900rpm.
    These governors are SWVS (single weight variable speed), and I really would love to see them set at 500 because this 42 foot Uniflite is quite fast even at low idle which means I have to constantly engage and disengage the Twin Disc transmissions when backing into my slip or maneuvering in close quarters.
    There seems to be a lot of this and that out there, but I haven't really found anything substantial that explains the "how to" in sufficient detail.
    I know the governors are touchy business that need finesse, but even then, it's not easy to find an experienced mechanic to guide me, so I would like to know what you find out about this issue.
    Thanks,
    jim

  5. #5

    Default Re: JT 671 TIB Idle Speed

    Hi guys. The problem with dropping your idle speed is governor droop. (rpm difference between neutral and in gear which is about 100rpm}. Dropping idle to 550 may cause hard starting and is so close to min. Gov speed could stall or surge. Stay at 650rpm. Also capitol ,zf and twin disc have a trolling valve which allows the trans to slip in gear at idle so that the prop turns slower.
    I tried the first capital gear trolling valve on my 8v92ti's with capitol 1.5:1 back in 1984. Worked excellent
    charlie w.

  6. #6

    Default Re: JT 671 TIB Idle Speed

    Ours idle at 550 no load, twin disc 507's I believe. There is no drop in RPM when it goes in gear, if anything they pop up to 600 or so under load.

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