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Ensign 735 Dual Tach-Sync and Hino EH-700...tach replacement?-gctid808261

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    Ensign 735 Dual Tach-Sync and Hino EH-700...tach replacement?-gctid808261

    I've got one of these on my 3818 in addition to analog tachs (except mine is in it's own enclosure instead of mounted into the instrument panel):




    I like it...but the display is separating inside the device, and it's barely readable now. I suspect (but could be wrong) that it's more accurate than the analog tachs...when the "sync" indicator flashes on, the engines certainly *sound* like they are sync'd, so that's what would lead me to believe that.

    These haven't been made in a couple decades from what I understand, and I occasionally spot one at a ridiculous price 20 years old. There's got to be a digital dual diesel tach similar to this somewhere. Or even two small digital tachs that will work with the existing signal. The wiring that carries the signal already goes up to the flybridge, so hoping that I could reuse that.

    Two questions:

    1) Does anyone know where that signal comes from on the Hino EH-700 engines, and if just any digital tachometer might work with it? Would two of the simple digital tachs made for gasoline engines work, by any chance?

    2) Anyone got any other ideas?

    Btw, if anyone has the part numbers for the Faria (?) analog tachs and/or analog temp gauges on our boats, I'll take those too! My indoor gauges look pretty good and seem to work well, but upstairs needs some replacements.

    Thanks!

    Dave

    #2
    There is tach sender on front of engine...you can take the signal form the same wire that your current RPM gauge uses.

    Any digital display will show more detail they an analog dial simply by the nature of the use interface. Ie numbers that are precise vs a needle that changes with viewing angle and must be interpreted.

    Call Faria or email them picture and they can tell you. On my 4588 each gauage has are part number sticker on it.
    Mark
    USCG OUPV
    1990 4588
    Carlsbad, CA

    Comment


      #3
      So, FloScan explicitly lists the FloScan 7500 digital tach/fuel flow meters as something that will work with the Hino EH-700 engines...model # 750M-BOS-2K Bl. It would require replacing the current analog tachs with two of these. However, these are crazy expensive...around $1K each. There's got to be simple digital tachs that will work with the Hino engines...I'll keep looking.

      The Ensign Dual Tach-Sync doesn't do anything fancy (like actually controlling synchronization of the engines)...it just reports RPM's and lights up the "sync" letters when they are running within 10 or 20 rpm's of each other. That said, i think it's useful to have the analog tachs plus digital tachs...I can get them close easier, and hear with my ears when they are actually sync'd.

      UPDATE:

      I found a used Aqua Meter Ensign 735 on ebay...cost more than I wanted to pay, but it appears to be a working one. I'll switch it out with the failing one I have now, and see if I can get a couple more years out of it. In the meantime, I'll keep my eyes open for better alternatives. The FloScan combo instruments certainly look nice, and I'd probably seriously consider that if we were doing extended cruising...but we're not. Nowadays it's weekends and an occasional week of vacation, so gotta keep the expenses reeled-in for nice-to-have's that aren't truly necessary at the moment. If this used one works well enough to read AND I replace the analog tach that's registering wrong, that should be sufficient for now.

      On an older boat, I do think it's good to have backups to crucial things...these boats have two engines, two trans, two fuel filters, two tanks, etc., so that's a good start. I've got two GPS chartplotters (plus paper charts if necessary), a depth-sounder plus forward-looking sonar (two sources of depth info), and at least there is a 2nd set of gauges downstairs that seems to work reliably...having good analog tach and temp plus the digital tach feels like a reasonable backup if one goes out on a trip, etc. I've still got one analog tach and one analog temp gauge that I need to replace (and if the temp gauges are not ridiculously priced, I may just replace both of the ones upstairs), so going to pull those out and collect the part #'s over the next weekend.

      Dave

      Comment


        #4
        I have flowscans and put them 15 years ago, with EH700...the model I have I believe is 7500 and they have been rock solid, pretty simple install just time consuming with running wiring and plumbing into fuel lines.

        http://www.floscan.com/html/blue/ser...?sid=2&catid=2
        Mark
        USCG OUPV
        1990 4588
        Carlsbad, CA

        Comment


          #5
          I got this replacement Ensign 735 dual tach hooked up, and...it powers up, but the starbord side doesn't register anything other than 0. (I know the wiring is good, because the old one registered on both sides...the display was just becoming unreadable, had to actually press on it to be able to see the numbers.) Gah!

          One good thing I noticed though...once I removed the old Ensign, the analog tachometer on the port side started registering correctly (or what appears to be closer to accurate...it was under-registering before). So, I'll bet the old Ensign was sucking so much current from that circuit (it appears to be wired into the analog tachs) that it was causing the analog tach to malfunction.

          So...I'm now wondering if I truly need this gadget anyway. The analog tachs might not be 100% accurate, but you can definitely hear the "beating" disappear when the engines are in sync. I'm asking myself "do I really need this?". Thinking in terms of having a backup...if one of the analog tachs fails (say, on a trip), then I can still judge the rpm's of both engines by checking the one working tach and listening to whether the engines are close enough to in-sync. I think I might just remove this old Ensign crap altogether, especially since the port-side analog tach seems to be functioning properly now. If I start to feel like I do actually need digital tachs in addition to or instead of the analog tachs, then I'll look at something newer than these old failing Ensign 735's.

          There ya go...

          Dave

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