This what a burned out capacitor looks like.

sbw1

Well-Known Member
Oct 10, 2006
8,183
West Michigan
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My 5kw WB genny suddenly started putting out just 65 volts plus or minus 10 volts. Trouble shooting determined it was one of two capacitors that sit side by side. One good and one bad. Replaced them both and adjusted output to 60 hertz with a load of water heater, A/C, ice maker, and battery charger all running. Nice clean genny power now that looks just like shore power on the meter. Lasted 14 years and about 320 running hours. The genny has been a little funky this year but was was making enough power to run all the stuff we use until last week. Glad it failed when we got home from cruising instead of when we were still on vacation.
 
That's a lucky break. I had mine go out on me last year. The genny would only put out 60 volts like yours, but I was able to make it work by turning on the hot water heater for some reason.
 
That's a lucky break. I had mine go out on me last year. The genny would only put out 60 volts like yours, but I was able to make it work by turning on the hot water heater for some reason.
I learned that these items commonly fail after so many hours of use. Not sure why they overheat but heat eventually does them in.
 
Nice work! Where did you get the capacitors? WB or aftermarket. I think they are $60 from WB and about $7 elsewhere.
 
Nice work! Where did you get the capacitors? WB or aftermarket. I think they are $60 from WB and about $7 elsewhere.
They are WB. Yep, about $55. Know WB is pricey, but have no way of judging the quality of a $7 generic product and the access is not easy on my boat so went with OEM. I believe they are essentially foil layers separated by heavy paper layers, and encased in a plastic wrap. Probably made by children in China for a few cents. Hopefully these will fail in 14 years on someone else's watch.
 
Agreed. I had the very same problem last summer and an authorized WB service provider changed mine out for $900. I was leary of taking on this job so I outsourced it, which is very rare for me. How difficult was it? I have very good access to my genset so take that out of the equation.
 
Agreed. I had the very same problem last summer and an authorized WB service provider changed mine out for $900. I was leary of taking on this job so I outsourced it, which is very rare for me. How difficult was it? I have very good access to my genset so take that out of the equation.
Two hours of labor. Thirty minutes is getting into position, moving the remote coolant tank, taking the cover off. Then same putting it all back. Remove and replace parts, turning stuff on so getting out of the bilge to do that. Back into bilge and adjusting rpms. Not hard, but inconvenient.
 
Wow, and I mean WOW. These guys charged me for 7 hours of labor for this same issue. I knew what it was from doing some reading, as did they just from the evident symptoms. Their place is 20 min from my marina so travel time isn't accumulated. I had/have no choice b/c they are the only WB people in our area and when you mention "gas generator" problem to any marine mechanic it's like holy water to a vampire.

I need some schooling on these stupid generators.
 
Boats are not designed for maintenance. They are like blivetts. (A quart of diarrhea in a pint container)
 
Two hours of labor. Thirty minutes is getting into position, moving the remote coolant tank, taking the cover off. Then same putting it all back. Remove and replace parts, turning stuff on so getting out of the bilge to do that. Back into bilge and adjusting rpms. Not hard, but inconvenient.

Mine was pretty easy to get to, unlike the circulating water pump. It was inside the control box right in front. Took me the same amount of time as yours. Most of it was getting in position as you said.
 
Wow, and I mean WOW. These guys charged me for 7 hours of labor for this same issue. I knew what it was from doing some reading, as did they just from the evident symptoms. Their place is 20 min from my marina so travel time isn't accumulated. I had/have no choice b/c they are the only WB people in our area and when you mention "gas generator" problem to any marine mechanic it's like holy water to a vampire.

I need some schooling on these stupid generators.

Was this on your new genny Ron? Well I guess it's a three year old genny now!
 
My friend has a 2000 380da and has no power shown at breaker panel from his gas geni. Marina is telling him he needs entire backend of geni replaced for $4,000. I highly doubt they looked at the capacitors, let alone put a voltmeter on the geni output. I realize this is not a lot of info, but does anyone have any pics of what cover I need to remove to get a look at the capacitors? Thanks.
 
My friend has a 2000 380da and has no power shown at breaker panel from his gas geni. Marina is telling him he needs entire backend of geni replaced for $4,000. I highly doubt they looked at the capacitors, let alone put a voltmeter on the geni output. I realize this is not a lot of info, but does anyone have any pics of what cover I need to remove to get a look at the capacitors? Thanks.
What brand of genny does he own? The WB panel you remove is the one with a grill on the back end of the unit. "Getting a look at the capacitors" is not straightforward if you have never worked on one of these devices before. Capacitors store upwards of 5-6 hundred volts and can kill you if you start probing around the wires with your fingers or even a screw driver. A more likely cause of no voltage is the stator windings have failed. There are specific things to test for voltage including diodes, rectifiers, windings and capacitors. If you are not familiar with reading electrical diagrams, multimeters, and testing procedures, you can do some serious damage to yourself. At the very least, you will want to download a repair manual before opening up the unit and getting a look at things.
 
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I learned that these items commonly fail after so many hours of use. Not sure why they overheat but heat eventually does them in.

They look like electrolytic capacitors. If so, what's inside is a liquid electrolyte that holds the charge. Over time (and heat) the electrolyte dries up and the capacitor fails. Heat accelerates this process A LOT.
 
My friend has a 2000 380da and has no power shown at breaker panel from his gas geni. Marina is telling him he needs entire backend of geni replaced for $4,000. I highly doubt they looked at the capacitors, let alone put a voltmeter on the geni output. I realize this is not a lot of info, but does anyone have any pics of what cover I need to remove to get a look at the capacitors? Thanks.

Based on all my research and reading the great WB manual for my 7.6KW diesel version. The 60V issue usually a cap issue and the added load exictes the generator and it starts generating, so that is why adding load will kick it over sometimes. The completely 0V issue is usually a diode issue and the diodes are in series on the rotor windings, so you need to pull the backend. Then get friendly with a lot of copper. It's usually faster/cheaper to purchase a rewound backend and exchange the failed one. Backend is about $2900 plus the labor to pull the old and install the new comes in around $4000. Easy to check the output, remove the cover next to the breaker and put a meter on it. I would hope the yard did that much at least!!!! LOL...

Good Luck!!
 
I went through a problem with my WB 7.0 BCG gas genny last year.
Online manual in hand I trouble shot the caps, diodes and windings.
I had a problem with the windings. Fine because it’s 20+ years old.
Pulled it out for a winter project. Had a new back-end shipped to the house. Replacement was pretty easy compared to many boat problems. Also, gave me a chance to go over the whole unit and do anything it needed to look and operate like new :)
 
Carter, my gen is in it's 5th season. It has now blow 2 caps (during the 4th season) and the carb got all temperamental early in the 5th season (thus the replacement), all of these issues to the tune of $2k (WB has a crappy 5 yr warranty - after the first 2 years only major engine issues are covered).

Who knows what season 6 holds in store.
 
Carter, my gen is in it's 5th season. It has now blow 2 caps (during the 4th season) and the carb got all temperamental early in the 5th season (thus the replacement), all of these issues to the tune of $2k (WB has a crappy 5 yr warranty - after the first 2 years only major engine issues are covered).

Who knows what season 6 holds in store.

Your boat is a 2001. Has the generator been replaced and now 5 years old or is this your 5th season and the generator is 17 years old? FWIW it could be worse you could have a Kohler.
 
Gen replaced in fall of 2013.
They ALL suck. Red ones, white ones - doesn't matter...unless they're diesel powered.
 

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