Troubleshooting Westerbeke 7.0 BCGB- Need guidance

Discussion in 'Electrical Stuff' started by amajamar, May 22, 2019.

  1. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    Generator produces almost no AC power (8-10VAC) when running at specified 1800 RPM. When engine speed is increased to about 2000 RPM, 108-120 VAC is produced, but frequency is too high (>65 HZ).

    Does this sound like a diode problem, capacitor problem (there are two in my generator), or a winding problem (I hope not...)

    Thanks in advance!
     
  2. Chris-380

    Chris-380 Active Member

    198
    Jan 20, 2019
    Pontoon Beach IL
    380 Sundancer 2000
    454 Horizon w/V drives
  3. Chris-380

    Chris-380 Active Member

    198
    Jan 20, 2019
    Pontoon Beach IL
    380 Sundancer 2000
    454 Horizon w/V drives
    i would think this is your problem
    -Residual Voltage 4-6 VAC (Hot N) at No-Load, just a little off on the readings

    this is the possibilities
    -Faulty capacitor (two)
    -Open exciter
    -Shorted exciter
    -Engine speed (hertz) is too low
    -Electrical connections are faulty

    Maybe put a resistive load on (like a space heater or hair dryer) and see what the voltage does.

    Wish i had more experience in generators

    Here is a good source also
    https://www.westerbeke.com/troubleshooting guide/bc_troubleshooting_manual.pdf
     
  4. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
  5. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    Yeah, I'm going to go after capacitors. If diodes were bad, probably no voltage at any speed.
     
  6. 370Dancer

    370Dancer Active Member

    842
    Oct 2, 2006
    Florida - Alabama
    1998 370 Sundancer
    380hp MAG MPI Gen VI with V drives
    On my 1998 7.0BCG the caps had changed value over time, and so did the resistance of the windings.
    I experimented with some different capacitance values, and found lowering the value a bit put me back in "spec" so the exciter started working correctly.
    A symptom at one point was no A/C voltage until you turned on something like the water heater, then it would suddenly jump up. Then it would jump up but not to 120V. Replacing the caps and adjusting the tap selector wires put me back within 120V at 1800 RPM 60 cycles.
     
    Chris-380 likes this.
  7. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    What timing...I've been waiting a little over a week to have my marina come look at my Westerbeke 7.0. I'm hoping they make it out tomorrow to look at it. I believe I also have bad caps or diodes but access to the front end of my generator is nearly impossible. I hope your 380 is better!
     
  8. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    I had a conversation with my local Westerbeke parts and service center. I found them to be relatively helpful. The person I spoke with pretty much indicated that if it was a diode issue, there would be no AC power at all, and he said it sounded like capacitors to him. He did say it could be something else, and did recommend doing a full troubleshooting. Capacitors are not expensive, so I'm going to go that route.

    Not going to be easy to do, probably painful, but going to give it a go!
     
  9. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    I'm having the same symptoms, so I'm hoping the new capacitors is the main issue.
     
  10. rondds

    rondds Well-Known Member SILVER Sponsor

    Oct 3, 2006
    Jersey Shore
    2001 380DA
    Merc 8.1s (2008)...Hurth ZF 63 V-drives...WB 7.0 BCGD (2013), Garmin 8208 & 740 MFDs, GMR 24xHD dome
    It was capacitors on mine. Pls take pix (if you can) on this repair!
     
  11. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    So, capacitors are replaced! Not exactly fun, but not too bad. Hardest part is getting them back into their brackets and tightened. Especially by using a mirror and trying to feel your way through it.

    Notes to know if you are going to attempt:

    ENSURE THAT YOU DISCHARGE THE CAPACITORS BY BRIDGING THEIR TERMINALS WITH A SCREWDRIVER BEFORE ATTEMPTING TO REMOVE!

    The left side cap is easy to remove, harder to replace due to the bracket issue. Make sure you have access to the back side of the case because you need to remove two screws that hold the bracket and the fuse holder bracket. They are integral to one another. To remove the right side cap I needed to remove the screws that hold the electrical junction block (be careful not to drop screws or washers into windings) to allow clearance for the cap to pass. In addition, remove the cover of the circuit breaker box, remove the exterior plate from around the face of the breaker (four little screws), pull the breaker back and out of your way, and if you cannot see the recessed screw that bolts the capacitor bracket, loosen the 10mm nut holding the white ground wire and rotate the ground wire until you see the screw. There is a nut (8mm) and lock washer on the bracket side (difficult to see because the AC supply wires bundle is directly in front of it). I did not remove them (I loosened it up quite a bit, though), as I was concerned about dropping anything into the winding area. Getting the capacitors into the brackets was hard to do. I used some electrical tape to hold the top of the brackets from rotating back while slipping the caps into them. That was the hardest part, due to not really being able to get my hands (or eyes really) in the proper position.

    Here is a photo of the problem cap!

    IMG_20190523_173902.jpg
     
    Last edited: May 23, 2019
    rondds and Chris-380 like this.
  12. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    Now I need to address why it surges when not under full load... Gonna' go after rebuilding the carburetor next...:(
     
  13. LG111

    LG111 Active Member

    532
    Jan 4, 2015
    NW
    410
    8.1
    When was the oil changed last in the governor? This needs to be done ever 300 hours to prevent surging and maintain rpm under load.
     
  14. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    I did it a few weeks ago when I was attempting to tune up the genny.
     
  15. LG111

    LG111 Active Member

    532
    Jan 4, 2015
    NW
    410
    8.1
     
  16. rondds

    rondds Well-Known Member SILVER Sponsor

    Oct 3, 2006
    Jersey Shore
    2001 380DA
    Merc 8.1s (2008)...Hurth ZF 63 V-drives...WB 7.0 BCGD (2013), Garmin 8208 & 740 MFDs, GMR 24xHD dome
    Great stuff and nice work. So the bad cap was visually messed up too? Thanks for this info. I paid about $2k to a WB guy to do this job 2 summers ago. Never again!
     
  17. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    Yikes!... The capacitors cost me $28... for both...
     
  18. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    I'm hoping mine is the caps. The marina came out Wednesday, got 4 volts on the gauge and called to tell me "its something major, will get back into it next week to check deeper". Not ideal.....Hopefully they start with the cap's/diodes and not a full engine and generator removal from the boat. ha. :)
     
  19. amajamar

    amajamar Member

    133
    Sep 9, 2013
    Wareham, MA
    2001 380 Sundancer
    8.1S Horizons
    As long as there is enough clearance to the back end, the capacitors and diodes are probably serviceable with the generator in the boat. I have about a foot between it and the fuel tank, so it was doable.
     
  20. 370Dancer

    370Dancer Active Member

    842
    Oct 2, 2006
    Florida - Alabama
    1998 370 Sundancer
    380hp MAG MPI Gen VI with V drives
    Mine were 6 bucks. Westerbeke doesn't manufacture capacitors any more than they do raw water pumps or the engine for that matter. Sometimes it takes a deep dive to get past Sea Ray's part numbers to the OEM, and Westerbeke's to the OEM.
     

Share This Page

Show Sidebar