tachometer

Discussion in 'Sport Yachts/Yachts' started by ynot, Jan 25, 2017.

  1. ynot

    ynot Member GOLD Sponsor

    73
    Feb 14, 2010
    s ca
    400 sedan bridge
    454 mer
    hello boaters
    anyone had experience with fixing or calibrating sea ray sedan bridge Tachometer's ?
    mine fluctuates a lot having difficulty keeping track of rpm
    any help is appreciated
    thank you
     
  2. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    You don't say what year or type of tachs you have. Since you have gas engines I will tell you to remove the tach and look on the back, on some models there is a very small adjustment screw-type head for setting the tach for 4, 6, or 8 cylinder. For some reason the contacts in the tachs get cruddy. With a very small screwdriver turn the screw back and forth a few times from 4 to 8 and then return to the "8" position for your engines. This usually cures you kind of issues. However, I am assuming you have those types of tachs.
     
  3. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    Sea Ray uses Teleflex tachometers and gauges. If messing with the settings on the back doesn't clear up the fluctuation, you need to replace the tachs. They aren't horribly expensive and it is an easy job to replace them. To get exact replacements with the SR logo, you will have to go to a Sea Ray dealer and order them (diesel versions were about $175 a few years ago).
     
  4. ynot

    ynot Member GOLD Sponsor

    73
    Feb 14, 2010
    s ca
    400 sedan bridge
    454 mer
    thank you gents
    ill go to my boat tis weekend ad try that
    my best
     
  5. BurgundyS24

    BurgundyS24 Member

    426
    Oct 5, 2014
    Napa, CA
    Sea Ray S24. full delta enclosure. Towed by 2007 Chevy 3500 duramax/allison combo.
    350 with closed fresh water cooling
    My teleflex gauges also did this... I accessed the tach and flicked the switches back and forth and it started reading more true.


    Sent from my iPhone using Tapatalk
     
  6. 920richardf

    920richardf Member

    72
    Dec 25, 2007
    Great Lakes
    2000 410DA
    CAT 3126TA
  7. THJeff

    THJeff Member

    205
    Jan 4, 2012
    Rochester Hills, MI/Belle Maer Harbor/Club Island
    2000 410 Sundancer
    CAT 3126 Diesels
    My tachs have never been right since I've owned my boat but last year the port tach pretty much stopped working altogether. I've read several threads here about pulling the tachs and cycling a cylinder switch in back. Is this the same process for tachs with diesel engines? If not, can this re-calibration be accomplished some other way for tachs with diesels?
    I'm tempted to just replace them since they are the original tachs. Are the Aetna digital tachs still the best ones to use? For those that have made this upgrade, which model is better 8905R or 8402?:
    http://www.aetnaengineering.com/model-8905r-lcd-tachometer/
    http://www.aetnaengineering.com/model-8402-led-tachometer/
    Lastly, if I go this route and replace them, is it possible to advance the hour meter to the current number of hours on the engines?
     
  8. TNT8808

    TNT8808 Member PLATINUM Sponsor

    158
    May 25, 2016
    West Michigan
    2008 48 Sundancer
    Cummins QSC 540's
    Avon Seasport 340
    40 HP Yamaha
    When I had my 410 with CAT 3126's I went through the headache of trying to adjust many times, and even replaced the originals with another set of new Teleflex tachs. I still had issues as they just weren't accurate enough. I finally bit the bullet and bought the Aetna digital 8905R-P-H's. They're smaller, so here's some pics of what I ended up doing. I kept the inside of the old tachs for the future if someone wanted to verify hours in addition to writing the hours on them. It was actually quite simple to do, and the digital tachs worked flawlessly.
    IMG_2393.JPG IMG_2394.JPG
     
  9. THJeff

    THJeff Member

    205
    Jan 4, 2012
    Rochester Hills, MI/Belle Maer Harbor/Club Island
    2000 410 Sundancer
    CAT 3126 Diesels
    Thanks that looks great. Do the old tachs pop out of that housing somehow so you can just insert the new ones or did you have to get creative by cutting and such? Also what are your thoughts on getting the black bezel instead of the polished if going that route since the inside is all black anyway?
     
  10. TNT8808

    TNT8808 Member PLATINUM Sponsor

    158
    May 25, 2016
    West Michigan
    2008 48 Sundancer
    Cummins QSC 540's
    Avon Seasport 340
    40 HP Yamaha
    Once you remove the old tach from the dash you'll see it basically has a plastic can on the back that holds everything in, and has the clamp mechanism attached to it. I cut the "can" in half on my band saw gently and turned it as I went so as not to harm anything on the inside. Once the "can" was off the guts of the old tach came right out surprisingly. The Aetnas fit perfectly, and I used a little silicone to hold them in place. When the silicone dried I glued the other end of the can back on, and used the original clamp to install it back in the dash. If I were to do it again, I would definitely get the black bezels. When I ordered mine I ordered them in the stainless finish so they'd match the other gages as I thought I end up either making a new dash or making up for the difference in size some other way. Then this idea just kinda hit me so I tried it and it worked out great.
     
  11. THJeff

    THJeff Member

    205
    Jan 4, 2012
    Rochester Hills, MI/Belle Maer Harbor/Club Island
    2000 410 Sundancer
    CAT 3126 Diesels
    Thanks again for your replies. So the old "can" is part of the dash and not the old tach? If that's th case, you cut the "can" while it was still attached to dash? You describe it as the Aetnas popping in the hole but from the picture it looks like the bezel is on top of the housing...just not sure how you got it to have such a finished look.
     
  12. TNT8808

    TNT8808 Member PLATINUM Sponsor

    158
    May 25, 2016
    West Michigan
    2008 48 Sundancer
    Cummins QSC 540's
    Avon Seasport 340
    40 HP Yamaha
    The "can" is part of the old tachs. When you remove your dash panel you'll see what I'm referring to. Once you cut the "can" in half, and pull the old tach out it will all make more sense. When you look at the tach from the front, the beveled part and the flat area where the needle is are actually two separate pieces.
     
    THJeff likes this.
  13. Jaws

    Jaws Member GOLD Sponsor

    521
    Nov 13, 2007
    Sarnia, Ontario
    460 Sundancer 2002
    Cummins 8.3 6CTA
    I finally put my Aetna tachometers up on the dash this fall but I had a machine shop make a couple of adapters from polished aluminum.
     
  14. THJeff

    THJeff Member

    205
    Jan 4, 2012
    Rochester Hills, MI/Belle Maer Harbor/Club Island
    2000 410 Sundancer
    CAT 3126 Diesels
    I was at the boat today and removed the dash panel and see the "cans" you're referring to. I don't see any way to disconnect these cans from the dash panel. I removed the bracket, disconnected the wires and all I can do is twist it; it nothing will pull off from the back. Did you cut the "can" in half while it was still attached to the dash panel? This doesn't seem right as how would the whole unit be replaced if you just swapped in the same tach as the old one? Perhaps I'm missing the obvious, but I just don't see how the can is detached from the back of the dash panel.
     
  15. TNT8808

    TNT8808 Member PLATINUM Sponsor

    158
    May 25, 2016
    West Michigan
    2008 48 Sundancer
    Cummins QSC 540's
    Avon Seasport 340
    40 HP Yamaha
    You were soooo close, but went the wrong direction. Once you remove the bracket (clamp), tach comes out from the front of the panel.
     
  16. THJeff

    THJeff Member

    205
    Jan 4, 2012
    Rochester Hills, MI/Belle Maer Harbor/Club Island
    2000 410 Sundancer
    CAT 3126 Diesels
    I was missing the obvious. So just push on the can toward the front of the panel and it will pop out, front display lens, chrome bezel and all? When I was twisting it, only the tach inside the lens was moving. The bezel/lens on the outside weren't moving at all. That's why I though it had to come out from the back and the lens/bezel were attached to the panel.
     
    Last edited: Feb 3, 2018
  17. TNT8808

    TNT8808 Member PLATINUM Sponsor

    158
    May 25, 2016
    West Michigan
    2008 48 Sundancer
    Cummins QSC 540's
    Avon Seasport 340
    40 HP Yamaha
    Yes, the whole tach will come out in one piece. Apparently yours is either stuck from age, or someone removed it previously, and added a little something to secure it in place.
     
  18. k9medic

    k9medic Member

    456
    Mar 27, 2013
    Florida
    2005 23' twin engine jet boat
    1998 420 Aft Cabin
    twin jet 160hp.
    twin 3116 CATs
    Go Aetna digital tachs and don't look back.
     
  19. THJeff

    THJeff Member

    205
    Jan 4, 2012
    Rochester Hills, MI/Belle Maer Harbor/Club Island
    2000 410 Sundancer
    CAT 3126 Diesels
    Thanks.
     

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