Westerbeke 8.0 BTDA kicking my arse

Discussion in 'Electrical Stuff' started by ZZ13, Dec 11, 2020.

  1. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Helping a friend figure out his Westerbeke 8.0 BTDA issues. Here are the facts:

    - 2001 Generator
    - Two oil pressure switches. One on top is "auxiliary" and is for System Monitor, one on bottom is primary and is used for low oil pressure shutdown
    - Temp gauge and oil gauge, or their senders, don't work
    - Remote panel start switch blows 8A fuse when in "on" position. Replaced start switch - no change.

    With remote panel plug disconnected from back of control box to remove the remote panel as a variable, the following exists:

    - 8A fuse blows when auxillary oil pressure sensor is plugged in when starting from generator toggle switches
    - with auxiliary oil pressure sensor unplugged, it starts fine from toggle switches and continues to run while preheat is held on. As soon as preheat is released, generator shuts down (but 8A fuse does not blow).

    So, I'm working on a sequence of debug and isolation steps to get to the bottom of this. I first plan to get it working normally with remote panel disconnected by replacing auxillary oil pressure switch and also jumper the three shutdown switches to see if any of those are bad. Is there a tried and true process to isolate a gauge failure or a sender failure?
     
  2. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives

    This sounds like what I had about a year and a half ago. There is a diode in the circuit as I recall that failed, and allowed current to backflow into part of the start circuit and blow the fuse. I went through about 20 fuses trying to diagnose.

    Let me see if I can find that thread...
     
    Last edited: Dec 11, 2020
  3. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    This is the whole saga. In part #3, the diode that was causing the problem (its in the on generator control box). You can buy these online cheap, or pay $50 for some westerbeke repackaged.

    Part 1 --> http://clubsearay.com/index.php?threads/7-6btd-blowing-8a-fuse.93704/

    Part 2 -->http://clubsearay.com/index.php?threads/7-6btd-blowing-8a-fuse-part-2.93843/

    Part 3 --> http://clubsearay.com/index.php?threads/7-6btd-blowing-8a-fuse-part-3-bad-diode.94335/


    This is the diode to replace --> http://clubsearay.com/index.php?threads/generator-diode-replacement.94608/
     
    Last edited: Dec 12, 2020
    blaster likes this.
  4. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Thanks! I've been through 12 fuses so far. Thought I already had the record. Ha!
     
  5. my3sons

    my3sons Well-Known Member GOLD Sponsor

    Feb 24, 2009
    NY (Lake Erie)
    2004 400DB, Onan 9 kw Gen, Highfield RIB,
    Cummins 6CTA M-3
    David's answer looks like one from someone who knows what they're doing. I'm not that guy this time, but the sender should be able to be checked with a continuity meter. Or ground the sender terminal to the bat negative or the engine block. If gauge goes to max, it's the sender.
    If nothing happens, ground the sender terminal on the back of the gauge, if nothing, gauge is shot. If the gauge works, there's a break in the wire from gauge to sender.
    That said, I know nothing about Westerbekes. That's just old school testing.
    Don't take my word for it, I usually call you for electrical answers. :)
     
  6. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    So I think the diode is bad. I got OL as expected reverse biased. But I got .001v or so forward biased rather than expected .5v or so. I didn’t remove diode to test it so don’t know if that mattered. Will do that now.
     
  7. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    I removed the diode and tested it. It was bad. Replacing the diode fixed the remote start problem. Remote start panel now works. The oil alarm switch for the system monitor was indeed bad. With the new oil alarm switch in the system monitor alarms at low oil pressure. The coolant over temp switch is bad (shorted to ground). I have it bypassed right now until I replace it

    But it still won’t stay running when I release bypass switch. Next is to try bypassing the exhaust temp switch in case that is also bad. That would mean one failure took out three switches and a diode! I guess it’s possible it isn’t actually building oil pressure. But I can’t tell because the oil pressure gauge has never worked in the four years he has owned the boat.
     
    dtfeld likes this.
  8. bahamabreisus

    bahamabreisus Well-Known Member

    Oct 25, 2007
    Hampstead NC
    500 dancer, previous 420,390,300 dancers
    detriot 8v92
    Have you checked the actual oil level in the motor, they have a low level shut off also. It needs to be right at the full mark.
     
  9. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Just did an oil change. We are right at the full mark. This generator did shut down for that a few years ago when we didn’t have it quite full enough. I’ll add a few drops at a time and see what happens. Does that “oil full” sensor exist where it can be tested or replaced?
     
  10. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    This is almost the exact scenario I had bad diode took out multiple switches. Took me a long time to diagnose/understand what was happening, hence the 3 long posts. The switches are cheap, easy so hopefully you have this fixed soon.

    Once I repaired mine, its been purring like a kitten...well maybe braying like an old mule!
     
  11. bahamabreisus

    bahamabreisus Well-Known Member

    Oct 25, 2007
    Hampstead NC
    500 dancer, previous 420,390,300 dancers
    detriot 8v92
    There must be a sensor, but I have no idea where it is. I am nowhere near my manual or I would try to find.
     
  12. bahamabreisus

    bahamabreisus Well-Known Member

    Oct 25, 2007
    Hampstead NC
    500 dancer, previous 420,390,300 dancers
    detriot 8v92
    this is the part # for the oil level switch, so it does exist somewhere.
    SWITCH - OIL LEVEL
    [​IMG]
    Part #: 041593
    Part Price: $285.40
     
  13. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Still haven’t solved this. Studied schematic and all three shutdown sensors are daisy chained between the output of the stop switch and the K2 run relay. Preheat switch bypasses that daisy chain and runs a direct path from the stop switch to the k2 relay. Generator starts normally but shuts down when releasing the preheat switch. Stop switch and K2 relay are verified as good. Have verified all three sensors as not open, including replacing the coolant temp switch. So somewhere in that daisy chain wiring or terminal connections is an open circuit. Hopefully I can find it.
     
  14. ttmott

    ttmott PhD in OCD TECHNICAL Contributor GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    What I found is the SR schematics were incorrect on my old 7.6BTD (2000 400DA) so when I was having run issues I ended up tracing every wire and drawing this. Mine ended up being a broken wire on the Emergency Stop Switch inside the potting; couldn't see it. Maybe it will help... I can email it to you also...
    upload_2021-2-9_18-52-14.png
     
    carterchapman likes this.
  15. PartnerShip

    PartnerShip Member

    76
    Dec 3, 2006
    Carolina Beach, NC/Key West, Fl
    400DB 2001
    Cummins 450C
    I took a 10 amp circuit breaker and soldered wire leads with insulated alligator clips on the ends to the terminals on the circuit breaker. Simply remove the fuse and clip the breaker in the circuit on the fuse holder terminals. No more blown fuses during trouble shooting
     
  16. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    After my issues, I have found that my Emergency Stop switch is intermittent. Its on the aft side of the control box, around the corner from the Preheat/Run/Stop switches.

    upload_2021-2-10_20-16-10.png
     
    techmitch likes this.
  17. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    upload_2021-2-10_20-18-49.png
     
  18. ttmott

    ttmott PhD in OCD TECHNICAL Contributor GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    If it starts then shuts right back down when the start button is released and you have checked the continuity through all of the sensors then possibly the relay in the Halon shut-down module is bad. To check - install a jumper on TB1 so the top two terminals shown in the above drawing are connected (this takes the Halon shutdown relay out of the equation. If it starts and runs fine then either that relay is bad or it is not closing when the remote switch is on.
     
    techmitch likes this.
  19. ttmott

    ttmott PhD in OCD TECHNICAL Contributor GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    Also SR uses that Halon relay box for the normal Ign on and Ign off for the generator It has to be functional for the generator to work at all - good, bad? I don't know... It's an unusual configuration from my perspective.
     
  20. ttmott

    ttmott PhD in OCD TECHNICAL Contributor GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    Edit - that is if the 8.0 is wired the same as the 7.6; double check.
     

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