Westerbeke 7.6 BTD Generator will not start

Deep in Depth

Deep in Depth

Member
Jun 3, 2010
61
Prescott, Ontario
Boat Info
2000 410 Sundancer, Raymarine Color HD Radar, E7D MFD, C127 MFD, AIS
Engines
Cat 3116TA
Well, my Genny has been working great all summer and I was just about to start winterizing it. I went to start the Genny, it starts for about 3 seconds while I am holding the pre-heat switch. Then, the 15 amp breaker pops. After I reset it I can crank again with the same results.


  • Gen cranks and starts for 3 seconds
  • shuts down and 15amp breaker on top of Genny pops
  • fresh oil
  • reset breaker and sequence is repeated
  • Battery great
  • Plugged into 50 amp shore power

Troubleshooting so far
  • Turn gen start/stop switch to first click. I did not attempt to start the Genny or activate the pre-heat switch. Leave it turned on for 10 seconds or less and 15 amp CB pops.

Here is the location of the wiring diagram:
http://www.westerbeke.com/WiringDiagrams/7.6_BTD_SRC_( 44734_rev_b).pdf

Thanks:huh:

Steve
 
So I am guessing during this initial start there is no load at all on the generator?

From you schematic I am guessing the unlabeled breaker (size, just has "circuit breaker on it") in the start up circuit path is the 15 amp breaker you are referring to in your post?

I know this is no help, but it seems that you may have a short somewhere, Can you disconnect the alternator perhaps as apparently you are getting battery start voltage? Is your 8 amp fuse good?
 
I am talking about the 15 amp CB. Batt volts are good. The 8 amp may not be present while installed in the boat. I looked in the SeaRay Manual and there is no CB that I can find for DC to the generator. I believe the engine would not crank or start momentarily if this 8 amp was blown. You suggestion on a short is probably most accurate or it is internal to one of the component coming off the 15 amp. I am going down on Friday to continue troubleshooting. I know how to bypass the OP, ET and WT switches. I was hoping someone may have seen this snag before. There actually isn't too much technical support for Westerbeke on the net.

Thanks for posting.


Pseudomind said:
So I am guessing during this initial start there is no load at all on the generator?

From you schematic I am guessing the unlabeled breaker (size, just has "circuit breaker on it") in the start up circuit path is the 15 amp breaker you are referring to in your post?

I know this is no help, but it seems that you may have a short somewhere, Can you disconnect the alternator perhaps as apparently you are getting battery start voltage? Is your 8 amp fuse good?
Click to expand...
 
Well I still cannot find a 15 amp circuit breaker from your schematics, I find one labeled 20 amp and one labeled just "circuit breaker," If I am reading your schematic correctly the voltage from your alternator is used through your circuits once the K-2 run relay is energized, so disconnecting the alternator would do no good, however if your alternator has a short when it is suppose to be supplying the 12 volts for the run circuits after your generator has started, the breaker trips and opens the voltage path.
 
You are correct about the CB. It is labeled 20 amps in the schematics and mine is 15 amps. Sorry about that. I overlooked that one. I just talked to the Westerbeke distributor and that is where I will start. He gave me some other suggestions to try and isolate the different systems. I will post my findings next week. :smt021

Thanks


Pseudomind said:
Well I still cannot find a 15 amp circuit breaker from your schematics, I find one labeled 20 amp and one labeled just "circuit breaker," If I am reading your schematic correctly the voltage from your alternator is used through your circuits once the K-2 run relay is energized, so disconnecting the alternator would do no good, however if your alternator has a short when it is suppose to be supplying the 12 volts for the run circuits after your generator has started, the breaker trips and opens the voltage path.
Click to expand...
 
Well these things operate in a simplified form like this as long as all safety circuits and fuel pump path are good, when you are first starting the generator, you are using battery voltage and the K-1 relay, then from looking at your schematics once the generator is started the voltage run through these same circuits but now comes from your alternator in your scenario (I do not have an alternator) through the K-2 run relay. So it seems that you are able to start, but when you should be getting the voltage to run from your alternator the circuit breaker is tripping and the relay de-energizes , so no voltage is available, and it shuts down. The circuit path from both the K-1 Start and K-2 Run are basically identical, except the initial start comes from the battery, and the holding (K-2 run voltage) comes from the alternator. So as long as K-2 stays energized, no safety, or fuel pump related hiccups develop all runs well.

What I have stated above is just a simple generic explanation, for a more detailed you would have to follow the schematics and test. I am not sure if your alternator has a built in regulator or not, I am making my guess about it possibly being the alternator as the generator starts. I will readily agree there are much more knowledgeable board member's here who may chime in and offer their assistance. Good luck!
 
Last edited:
I had same problem on a 10BTD. Turned out to be a short in the WT switch. Remove the wires and see if breaker still trips.
 
Agreed, I had the same problem with a 7.6 BTD and it turned out to be one of the 3 safety switches. I can't remember which one.
 
Great info from all and I will be doing the testing on Thursday evening. I appreciate all the comments and experience. It is priceless.
 
SUCCESS!!!! It didn't take long to troubleshoot my Genny. After all the advise I received from you on ClubSearay and from the Canadian Westerbeke Distributor, my chances for success were great. I did the following:

1.The breaker tripped with the start/ Stop switch in the first click or run position after about 10 seconds. Generator not running. If I tried to start, it tripped after about 3 seconds after the genny started then it died.
2. Disconnect the output side of the 20 amp thermal breaker (I was mistaken and thought it was 15). Westerbeke said this could be a trouble area as they weaken with age and heat. The breaker did not trip. I reconnected the output wire on the breaker.
3. Next was the oil pressure switch, the exhaust temp switch and the water temp switch which are your protection should there be an unwated condition in each system. I elected to start with the water temp switch only because it was easiest to get at.
4. I disconnected the two wires and repeated my steps. The thermal breaker did not trip.
5. I put a temporary jumper across the two wires and repeated the start process and the Genny started normally. This removes the overtemp protection. Use it wisely.
6. I used my ohm meter to check the switch and both terminals were grounded to the body. That is not good.
7. Parts on order but unfortunately, its bed time for our boat until late April.
8. At least I will sleep this winter knowing what the problem was and the fix for under $40.00.

Thanks again.Experience is priceless
 
You must log in or register to reply here.

Forum statistics

Threads
113,117
Messages
1,426,457
Members
61,032
Latest member
Brock340
Back
Top