Generator life expectancy?

b_arrington

Well-Known Member
GOLD Sponsor
Feb 21, 2007
3,469
Setauket, NY
Boat Info
Back Cove 37
AB Ventus 9VL
Engines
Cummins QSC 8.3 600
Assuming proper care, what's the life expectancy of a diesel generator?

I'm looking at a 2015 boat with a 6kW Kohler generator with 776 hours. It looks like its had proper maintenance, but I'm not sure sure what the meaningful service life is. Any ideas?
 
I think the key to a generator is to use it. I can't speak specifically for the diesel models, but I had a gasoline 5E I ran it all the time and never had problems. I also knew a fella with a houseboat, his gasoline Kohler had 5000hrs on it with no problems - just maintenance. 700+ hours on that generator tells me it worked and the owner used it.
 
We purchased our previous boat with less than 40hrs on the gen (05 dancer). After 5 seasons we sold it with over 800 hours. It never skipped a beat aside from from having to replace the fuel pump twice in those 5 seasons. Changed the oil at the recommended intervals and kept up with the zincs and impeller. Our new purchased DB has 120 hours on the onan gen. Looks as if it was recently replaced. Not sure due to defect or neglect but doubt it was over used.
 
On this boat the main engine has 500 hours and the generator 776. I understand the owner purchased it to do the great loop and with that done is now selling it. I would guess that they kept the generator running for AC and to keep the reefers cold. 500 hours on a Cummins diesel doesn't bother me in the least. As I said, I wasn't sure about the genny.

I think it's a good point that, as with most marine stuff, it's better to have it be used and maintained vs. let it sit.

For my own purpose the generator would probably be used more as well. I expect to be hanging on the hook in the summer with some AC going.
 
As with most Gen's it is use it or lose it... More die from lack of use, not overuse.
 
Lack of use, sea water drips and leaks and failure to maintain generators are the prime causes of generator failure.

I frequently run a 55 Viking sport fisherman for the owner who is a friend. The last time I checked the bilge & fluids was in early January and the generator had 10,600 hours on it. Ran fine and looked new. On this particular boat, the power steering and autopilot drive pumps are AC powered so the generator runs full time when you are running the boat and because the women folks don't sweat or shiver, the generator runs anytime the boat is away from her slip.

Generator engine hours isn't a real worry but you still need to do a mechanical survey on the generator that includes running it under full load for an hour or more, doing lube oil analysis and coolant analysis.
 
On this boat the main engine has 500 hours and the generator 776. I understand the owner purchased it to do the great loop and with that done is now selling it. I would guess that they kept the generator running for AC and to keep the reefers cold. 500 hours on a Cummins diesel doesn't bother me in the least. As I said, I wasn't sure about the genny.

I think it's a good point that, as with most marine stuff, it's better to have it be used and maintained vs. let it sit.

For my own purpose the generator would probably be used more as well. I expect to be hanging on the hook in the summer with some AC going.
btw, i see you are located in our regular summer hang out. What are you looking to upgrade to, dancer or bridge?
 
btw, i see you are located in our regular summer hang out. What are you looking to upgrade to, dancer or bridge?

Yes, we're in Port Jeff harbor. We spend most of the summer hanging on a mooring at the south edge of the northwest mooring area, just outside Setauket harbor. We hang with my inlaws on their '98 270 DA.

I rather wish it weren't the case, but I'm looking outside of Sea Rays for one of these. Its the only type of boat I can find with a single engine that cruises at 28 mph, that can also sleep 4.

081711btpn-4369.jpg
 
That’s a beautiful boat.
I’ve had my boat for two summers now and being kind of fuel conscious I was initially reluctant to run the genny a lot when I first got the boat.
Then I realized how fuel efficient the diesel generator is and I started using it a whole lot more.
We usually spend a day on the hook at least once a week. Although I don’t usually run it when we first drop the hook, I usually start it up when my wife starts putting lunch together so she can use the microwave and then keep it on until we get back to the dock later in the day so we can keep the AC blasting in the cabin and the water heater going for showers.
I’d probably keep it on all day, but don’t want to listen to it running.
 
We want to spend more time traveling and on the hook to a generator will be pretty key for that. We spend most weekends out on the boat in summer. My wife gets overheated pretty easily due to a health condition, and it's not good when that happens. For that reason we're going to have AC on the boat. The one I'm looking at has 3 units; 1 for the cabin below and 2 for the helm deck. It will be essential when sleeping out, and she can have a place to cool off during the day.
 
Most boat things, I like to think of time more than hours.
Proper maintenance is key.
Just replaced the electrical back-end on my 23 year old Westerbeke. Only 1200 hours but, had a short in one of the windings.
I hope to get 23 more years out of the engine part that purrs like a kitten at 1800 RPMs.
 
I have industrial customers that have 5 times the amount of hours on their generators. You see a ton of Koehler powers systems out in the field.
 
We want to spend more time traveling and on the hook to a generator will be pretty key for that. We spend most weekends out on the boat in summer. My wife gets overheated pretty easily due to a health condition, and it's not good when that happens. For that reason we're going to have AC on the boat. The one I'm looking at has 3 units; 1 for the cabin below and 2 for the helm deck. It will be essential when sleeping out, and she can have a place to cool off during the day.

The only downside to running it on the hook is when we have boats rafted up to us. Ours exhausts on the starboard side so we try to have smaller boats that people won’t be sitting on tie up to us on that side.
Ours was brand new in April of 2016 so it’s pretty quiet, or at least quiet enough that the stereo drowns it out.
Exhaust smell isn’t usually a problem since the afternoons are always windy and with the bow in the wind on the hook the exhaust blows back. It can still be annoying to anyone tied up on our starboard side though so that’s why we generally ask the smallest boat to tie up there.

BTW: The previous owner replaced the generator because of several seasons of problems with the old one, most of which he attributed to under use.
 
The generator starts before we leave the dock and does not shut down until we get back or slipped at another marina with shore power. The generator on the 52DB is very quiet; in fact about only the raw water splash is heard outside of the boat. Later this year we will be running the generator a bit less as the boat is getting it's batteries replaced with Lithium banks and inverter/chargers which will allow the AC power systems to operate for up to a couple of days then as required, the generator automatically comes on line to recharge the batteries or we need to make water.
Marine generators are continuous duty rated and need to be run with proper maintenance for best service life.
 
I am on my second the first lasted 6 months... The second was only used for 40 hours... Both where Hydrolocked... I am looking for number three now... I know how I hydrolocked the first one... The second time I have no idea how it happed...
 
These little gas engines used in generators are the same ones used in small vehicles overseas. Here's some math I've done...

If a vehicle travels an average of 30mph over it's lifespan (let's just say), then 1 hour of generator use is the equivalent of 30 miles. So a generator with 1000 hours on it is like a vehicle with 30000 miles on it. If the generator is running at 1800rpm and powering a 3/4 load, it's probably not working as hard as the car engine does (hills, changing rpm, etc).

Of course these numbers are just guidelines for simplicity. Also keep in mind the damp environment that a generator is sitting in is not helpful to its longevity, especially when it's used in salt water. It's all about proper maintenance and a lot of luck, and, YES exercise it regularly.
 
On this boat the main engine has 500 hours and the generator 776. I understand the owner purchased it to do the great loop and with that done is now selling it. I would guess that they kept the generator running for AC and to keep the reefers cold. 500 hours on a Cummins diesel doesn't bother me in the least. As I said, I wasn't sure about the genny.

I think it's a good point that, as with most marine stuff, it's better to have it be used and maintained vs. let it sit.

For my own purpose the generator would probably be used more as well. I expect to be hanging on the hook in the summer with some AC going.
The loop in a 270? I would be interested in details... I thought there were legs of the trip
requiring long distance between fuel
 
The loop in a 270? I would be interested in details... I thought there were legs of the trip
requiring long distance between fuel
No, not my 270 AJ. The boat I’m looking at was used for the loop. It has a much larger range. Now that it’s done the owners are selling.
 

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