Westerbeke 7.0BCG issues

I actually have a westerbeke parts supplier about a half mile from my marina. Mayfair power supply if I remember correctly. Walked in and 75 $ later I walked out. Not to bad but he new right away what I needed before I even handed him the cap. Just by telling him my problems he handed me the new one and told me the voltage range of the old cap was to low. He also told me tbat the 7.0bcg has 2 caps so u might be a little different then mine.

Hey searaydad what's the black crap coming out of the old cap?
 
Quick upate - over the weekend I checked the circuit breaker mounted under the control box, no luck. Removed back access panel and saw the diodes, and have ordered them and the capacitors. Will hopefully have all the parts by Friday and see if we can bring it back to life. Thank you everyone for the great input, trying my best to save from doing a $3000 R&R...

Bryan
 
Another update... Replaced the diodes and capacitors yesterday, started genset and am getting around 60-70 volts on my panel. I am pretty sure I connected the wrong leads on the capacitors. Trying to read the electrical diagrams now, wish
me luck.
 
The leads on the capacitors are labelled with numbers. You need to use the same set of numbers all around to make sure you are using the correct winding on the coil. They also control whether it is 50hz or 60hz.

Gene
 
Sorry for the delay in getting updates posted. I replaced the capacitors and diodes, but only have 75V showing on my panel down in the cabin. Spoke with a mechanic in my area who suggested we (he) check the RPM setting and voltage regulator. Diodes and capacitors tested OK, hope this doesn't get too out of hand.

Thanks for everyone's help.

Bryan
 
I'm having the same issue with my 6.5kW quicksilver generator, but I couldn't find any capacitors in the parts list to replace....any other ideas?
 
I'd say your mechanic is on the right track. The capacitors and diodes don't control the frequency, the engine speed does. 1800 RPM=60HZ, 1500=50hz. Everything has to work together. The connections on the board, and the correct engine speed will make the correct voltage. If you're at least getting 75v, I think getting the connections and engine speed correct will get you the rest of the way home.
 
I am not competent in the control board repair arena. When I needed to fix the air conditioning board in an old volvo, a company in texas walked me through the process. If you are in the same boat (no pun intended) Google rebuild control boards. There are a ton of companies who do repairs now.

HTH
 
I'm having the same issue with my 6.5kW quicksilver generator, but I couldn't find any capacitors in the parts list to replace....any other ideas?
Update on my situation. Mechanic replaced the voltage regulator and control board on mine, which fixed the problem :)
 
I actually have a westerbeke parts supplier about a half mile from my marina. Mayfair power supply if I remember correctly. Walked in and 75 $ later I walked out. Not to bad but he new right away what I needed before I even handed him the cap. Just by telling him my problems he handed me the new one and told me the voltage range of the old cap was to low. He also told me tbat the 7.0bcg has 2 caps so u might be a little different then mine.

I Have been dealing with genny issues all summer...a lot of testing, phone calls to people who have no clue, rpm checking etc etc etc...Finally came back to the CSR blogs and found your post. This is where I should have started!!!! I live in Michigan so your local company was surprised when I called. I told them where I learned about them here at CSR and they were really happy and impressed that they were mentioned.

My problem was at start up the voltage was at 105 volts...over the course of 10 minutes of running with no load the voltage would eventually get up to 118-120 but would "hunt" for a voltage to stay at...in other words it would vary at no load between 115 and 119v. The HZ were at 61.5-62 without any problem.
Upon adding a load, IE the aft AC, it would operate for a few minutes then cut off due to a low voltage supply. After explaining this to the tech person he immediately said..."your capacitor is bad!!" I said which one or both, he said "No, only 1, if they were both bad your voltage would be about 50-60v". So I followed his advice and ordered one.

I went to the boat today to remove them and see if either had a bulge and to my surprise, I am unable to remove one of them for this very reason. This guy was spot on! Thanks again for sending their information through CSR...it has saved me a boat tech. service call or worse yet, ordering parts that I didn't know would help or not.
 
The leads on the capacitors are labelled with numbers. You need to use the same set of numbers all around to make sure you are using the correct winding on the coil. They also control whether it is 50hz or 60hz.

Gene
Hey gene,
I know this is 3 years old, but I am having some weirdness with the genny now. Looking through this thread and trying to find other references. In regards to the exciter circuit I did find something that doesn't jive with your statement above, and this has been working for 10 plus years.
In the 7.0 BCG model, there are 2 capacitors. I removed the leads, and used a multimeter with uF reading capability, and read about 17.5 microfareds on each cap. the manuals all talk about 34 or so uF but don't speak of whether that is for each capacitor, which are supposedly hooked in series, or the total capacitance. They don't appear to be physically leading, but I have not removed them from the housing yet.
the schematic shows that the 2 caps are hooked up in series. Each cap has 2 sets of wires. One set is for 50hz or 60hz operation, and the other set has 3 wires labeled 7, 8, and 9.
In my case, looking at the generator end, the left cap had 60hz and #9 wire connected. On the right cap, it is 60hz and the #7 wire. That is in direct conflict with your statement above, but the genny has worked for quite some time.
Now, the engine is running fine, but I may get 60-70v for a few seconds, and then it drops to near zero on the panel meter and stays there. All subsequent starts are near zero. If I leave it for a day then I may get the 70v at startup again.
Any thoughts, since you did a lot of investigation on the wiring of these? What notes, photos etc might you have laying around?
2nd question, were you able to lift the genset out by removing the stbd engine manifold and riser only, or did you also have to disassemble some of the generator?
Not looking forward to this project, but the thing does have almost 1700 hours now.
I'll be doing some better resistance tests later. I did some on the terminals where 1 and 3 should have continuity, and 4 and 6 should have continuity, but they should not have continuity between those 2 legs or to ground. they were reading zero ohms across the 2 legs indicating a short, but I had not disconnected the other wires leading out to the breaker and so forth, so I can't say for sure my 2 legs are shorted.
 
Hello,

I have the 4.5 BCG and just went through a similar issue. See if this makes the generator output electricity...Start the generator with all the breakers using AC turned off. When you look at the panel if there is no voltage or a low number (mine was 60v) try turning on the hot water heater. Doing this made mine jump right to 120v and it worked perfectly after that. If the same thing happens to yours it's probably the capacitors.

As far as the terminals (numbers on the leads) mine use 60 & 8 but I only have one capacitor. Your technical manual states the 60 & 9 for each capacitor on page 136. Nothing about the #7 wire.
https://www.westerbeke.com/technical manual/38747_4.5-7.0bcg-a_technical_man.pdf
 
I struck gold early this morning. Westerbeke has a new edition of the bc_troubleshooting_guide.
https://www.dropbox.com/s/m8faqty8cyjsgnt/bc_troubleshooting_manual.pdf?dl=0

This 17 page guide answered all of my questions above.
First, My 1998 model 7.0BCG is a dual exciter model. This explains why there was no continuity between the 2 caps as Implied by most diagrams showing two caps.
Second, the guide is clear about having to remove the AC output wiring from the terminal block to properly ohm out the main windings. I'll do that when it gets light out.
Third, the dual sets of 7,8,and 9 wires for the capacitors are used in any combination to obtain the proper no-load voltage output of a properly running genset. So my particular unit was set up using #9 on one exciter, and #7 on the other.
Fourth, the dual exciter models use 18uF caps each, but I will be removing one to check the value for sure.

So, it looks like I am back to checking windings, and if they all prove to be good, then unsoldering the diode leads to check them, and the rotor windings. Meanwhile, if I can find a couple of caps, I'll swap them in temporarily to see if these are breaking down when excited.
 
Last edited:
I struck gold early this morning. Westerbeke has a new edition of the bc_troubleshooting_guide.
https://www.dropbox.com/s/m8faqty8cyjsgnt/bc_troubleshooting_manual.pdf?dl=0

This 17 page guide answered all of my questions above.
First, My 1998 model 7.0BCG is a dual exciter model. This explains why there was no continuity between the 2 caps as Implied by most diagrams showing two caps.
Second, the guide is clear about having to remove the AC output wiring from the terminal block to properly ohm out the main windings. I'll do that when it gets light out.
Third, the dual sets of 7,8,and 9 wires for the capacitors are used in any combination to obtain the proper no-load voltage output of a properly running genset. So my particular unit was set up using #9 on one exciter, and #7 on the other.
Fourth, the dual exciter models use 18uF caps each, but I will be removing one to check the value for sure.

So, it looks like I am back to checking windings, and if they all prove to be good, then unsoldering the diode leads to check them, and the rotor windings. Meanwhile, if I can find a couple of caps, I'll swap them in temporarily to see if these are breaking down when excited.

First: I have an extra 18uF cap that I purchased a couple years ago when I was having voltage issues as you discussed. I can ship it to you if you would liek to rty it...I won't be using it. Just private message me your address.

My story: When I was having the voltage issues as you have shared, I spent a lot of time on the electrical end of the generator checking everything you have discussed. I swapped out Caps, checked diodes, you name it I tried it. None of that worked.

I succumbed to calling in a marine generator expert. He listened to everything I tried doing and then said my issues had nothing to do with the electrical end (in my case anyway). It had everything to do with my mechanical governor. It was SHOT! It would not regulate the voltage properly and maintain the 1800 rpm's needed to get the 120 volts/60 hz. I thought he was a little off base because I did not know the correlation between the rpm's of the engine and the 60hz that is essential to running the voltage side of things. When he started working on it, he was more concerned about maintaining 60HZ than he was about 120v.

We ended up scrapping the mechanical governor and going with the electrical governor for a fraction of the cost. I have posted this information on an earlier thread.

In summary, I am not a mechanic by any stretch.. :) But I did have the same issues with my genny and we solved it at the other end of the unit. I don't know if it will help or not, but I thought I would chime in and shoot another idea by.

Let me know on the CAP if you want it.
Thanks
Bill
 
Hey gene,
I know this is 3 years old, but I am having some weirdness with the genny now. Looking through this thread and trying to find other references. In regards to the exciter circuit I did find something that doesn't jive with your statement above, and this has been working for 10 plus years.
In the 7.0 BCG model, there are 2 capacitors. I removed the leads, and used a multimeter with uF reading capability, and read about 17.5 microfareds on each cap. the manuals all talk about 34 or so uF but don't speak of whether that is for each capacitor, which are supposedly hooked in series, or the total capacitance. They don't appear to be physically leading, but I have not removed them from the housing yet.
the schematic shows that the 2 caps are hooked up in series. Each cap has 2 sets of wires. One set is for 50hz or 60hz operation, and the other set has 3 wires labeled 7, 8, and 9.
In my case, looking at the generator end, the left cap had 60hz and #9 wire connected. On the right cap, it is 60hz and the #7 wire. That is in direct conflict with your statement above, but the genny has worked for quite some time.
Now, the engine is running fine, but I may get 60-70v for a few seconds, and then it drops to near zero on the panel meter and stays there. All subsequent starts are near zero. If I leave it for a day then I may get the 70v at startup again.
Any thoughts, since you did a lot of investigation on the wiring of these? What notes, photos etc might you have laying around?
2nd question, were you able to lift the genset out by removing the stbd engine manifold and riser only, or did you also have to disassemble some of the generator?
Not looking forward to this project, but the thing does have almost 1700 hours now.
I'll be doing some better resistance tests later. I did some on the terminals where 1 and 3 should have continuity, and 4 and 6 should have continuity, but they should not have continuity between those 2 legs or to ground. they were reading zero ohms across the 2 legs indicating a short, but I had not disconnected the other wires leading out to the breaker and so forth, so I can't say for sure my 2 legs are shorted.

Well, it looks like you got the answer to the first question so I won't butt in here (or go crazy trying to find that info from four years ago unless you really need it). As to the second question, yes I removed the exhaust manifold to make room for the removal. I didn't do the removal and wasn't there for it, my yard did it and all I had to do was pick it up to bring it home for the winter while I worked on it. Removing the manifolds also gave me the opportunity to replace all of them since they were probably due. I believe in preventive maintenance.

Now that this thread is active again, I will monitor it to see if I can add anything, but I've already learned something new - take a look at the RPMs next time and inspect the mechanical governor. (Oh, so that's what that thing is....)

Gene
 
The diodes were not available from anywhere in the US I could find (back ordered), so I did order from SemiTech Germany, and they were shipped from Brazil. 10 bucks for both diodes, and $22 shipping. Nonetheless, not $100 plus shipping.

I have already purchased and replaced the capacitors with 18uF 450V units. I was still experiencing low voltage at 61hz (110v or so) at no load, and just about any load took the output voltage (perfectly govrened at 60hz) to 89-91VAC. That was with both caps using the #9 lead in the dual exciter.

I was pretty convinced that the diodes must be breaking down at load, so I put them in tonight. Exact same issue. So this got me to thinking that maybe the winding resistance has changed over time (maybe the reason for 3 different taps on the exciter windings for compensating), so I paralleled 2 caps on each exciter, raising them to 36uF each.

Now the no load voltage was 157v at 61 hz !! That was using leg #9 on both sides. I took them down to leg 7 on each exciter, and got down to 137v @61 hz. Even at full load the voltage was still high, so I have ordered 2 25uF/450V caps to see if I can get the taps to the middle #8, and still satisfy all specs.

Guess my only question is whether bumping the capacitance will shorten the life of anything. The initial resistance tests were pretty right on for all sets of windings, so it puzzles me, but not enough to stand still. Besides, it's a genset with over 1500 hours on it, so at some point it will be a boat anchor anyway. Any techies out there have an opinion about moving that spec?
 
Im getting 105 v no load. What did you end up using for Caps and where did you source them
Thanks
 
Using #9 taps, But haven't replaced my orig. 18 uF Caps ones. Have any extra ones your not using?
 
Read my story above about not being able to get to no load voltage until I changed the Cap value. I think it's the aging of the rest of the exciter circuit that changes the formula. Amazon has caps for dryers that are basically the same caps as what Westerbeke is sourcing. At 6 bucks each, they are a bit more palatable too. Try increasing your capacitance and see if your no load voltage doesn't come up to where it should be.
 

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