Generators. The Good, Bad and The Ugly

Looking for a used boat also means looking at used gen sets that come with them. Anyone willing to give feed back on what they think of the gen set that they have? For proper evaluation please include Brand, Size, What You Like and What You Don't. Any and all comments would be greatly appreciated.

Type:Onan 6.5 MKMD. came with boat, hour meter stuck @ 1370, I realized when it did not change. Reconditioned, according to Onan agent sticker, and paint over everything. Not the OEM genset.
Plus: Quiet, in sound shield, no vibration, starts easy, runs well, churns out power.
Neg: Had to replace start/stop solenoid. Screw mount fitting for fuel filter turned out deformed, fine just after changing filter, then leaked fuel, heaps! Mechanic found me a 2nd hand replacement. A water/exhaust gas separator might be good, despite no complaints received.

I have heard good things about Onan. Thanks.

Pgitug said:

Anyone willing to give feed back on what they think of the gen set that they have?.

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Sure. Our 1973 boat has a similar vintage Onan MDJE, 7.5kw, two cylinder diesel generator in it.

What I like about it: It was free. It works. It's a pretty robust unit. It puts out a lot of power if you need it. It's a low-speed generator (1800 rpm?) as opposed to the high speed units (2600 rpm?) so it doesn't have an annoying (to me) loud buzz. With regular use and proper servicing and maintenance, it has a reputation for lasting "forever."

What I don't like about it: It's much bigger and heavier than a modern generator. It puts out a LOT more vibration than a modern generator. The vibration has been known to cause problems with some of the circuit boards. Parts are expensive when you need them. It puts out more power than our boat needs. Wen have a propane galley so only need 5kw at most.

What we'll replace it with if it becomes too expensive to keep running: A Northern Lights generator of some 5 kw or so.

I never thought about the rpm issue. I do know that a unit that is too large for your usage is not a good thing. I see a lot of Northern Lights out there. Appreciate your comments.

Westebeke 12.5kw. Love it. More than enough kw for our needs. Best thing about it is it starts every time. Second best is it's very quiet.

Northern Lights 9KW

The good:

Perfect size for the boat. The quiestest generator in its class. Works perfect. You do not even know its running.

The bad:

Cost.

We have Northern Lights 20 KW and an 8KW. They came with the boat.

Good? So far, over three years, everything. Quiet (in sound shields), no vibration, no issues so far at all, maintenance is fairly easy.

Bad? Haven't really found any bad so far although as KSanders mentioned, if buying new, they are at the top end of the cost curve.

We have a Westerbeke 10kw in a sound shield. Easy to service. Not too loud. Reliably starts and runs as long as needed. We have reverse cycle heat/AC so we run it when we need heat, which is most of the time. Keeps the batteries charged and the water hot when we are not under way.

I plan to install diesel hydronic heat eventually. When I do, this generator will be way too big for my needs. We have a propane stove/oven too. Until then it is fine. Glad to have the power.

The Onan MDKD is 3 cylinder, the MDJE Marin has is 2 cyl. The MDKD also runs at 1800rpm, but does not have vibration. People onboard comment on its quietness, people on an adjacent boat who I told apologetically it would run for an hour said they had not heard it.
That said, there are plenty of other good brands out there. A good sound shield is a must.

We have a Northern Lights, came with the boat. Only complaint is the sound insulation had turned to rubbish and had to be replaced after eight years. Is that to be expected?

30 year old Westerbeke 8kw. Have replaced everything but the motor, including ac end (the windings). Have rebuilt the sound shield. Since we do not use airconditoning the biggest load is two large inverter chargers and a 1500 watt water heater. With all three units on the hertz drops from 61.2 to 57.5 for the first ten minutes. If had to replace would get Northern Lights 6.0 kW.

Marin said:

Sure. Our 1973 boat has a similar vintage Onan MDJE, 7.5kw, two cylinder diesel generator in it.

What I like about it: It was free. It works. It's a pretty robust unit. It puts out a lot of power if you need it. It's a low-speed generator (1800 rpm?) as opposed to the high speed units (2600 rpm?) so it doesn't have an annoying (to me) loud buzz. With regular use and proper servicing and maintenance, it has a reputation for lasting "forever."

What I don't like about it: It's much bigger and heavier than a modern generator. It puts out a LOT more vibration than a modern generator. The vibration has been known to cause problems with some of the circuit boards. Parts are expensive when you need them. It puts out more power than our boat needs. Wen have a propane galley so only need 5kw at most.

What we'll replace it with if it becomes too expensive to keep running: A Northern Lights generator of some 5 kw or so.

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Same genset, 1980 vintage, same experience. To that I'll add:

Outside the boat, no-one even knows it's running. Inside, it'll rattle your teeth right out of your head. The sound shield is old and not very tight, so I'm not convinced it's helping much. My problems so far have been with the raw water system, hopefully I've got them all addressed now.

I'm not ready to invest in a Northern Lights. If you find a used boat with one of those installed, that would be a huge plus. I will bring a Honda 2000i on longer trips as a backup, and try to keep the Onan alive for as long as I can.

I have a norprp. Have had no problems don't know the age I have had boat for 10 yrs. This gen came out another boat think it is 25 yrs old don't know I have 3800hrs on it. Now a boat that my friend has was new in 07 just replaced his kolher it had 2200hr it was braking down seveal times a year

Have a northern lights 4.5 kW with sound shield original to boat (25 years).
Pros: 1800 rpm, 3 cylinder, very quiet outside or on bridge/aft deck.
Plenty of power for normal use (no ac)
Reliable mostly.
Cons: would be very expensive to replace.
Somewhat loud in salon, but not excessively so.
Been very happy to have it, my last boat had a Kohler 5k 2 cylinder gasser; noises as a bastid'!

CaptTom said:

If you find a used boat with one of those installed, that would be a huge plus. .

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I just bought a boat that came with a 12KW NL generator. I've heard nothing but "good" about these sets......we shall see!

Have a 6 kw NL. Latches on enclosure are a bit of a problem. Had to replace exhaust elbow, 2007 vintage. Runs great and is very quiet. Exhaust is split, water exits under boat, gasses out the stern.

Kohler, 8EOZ, 8Kw, 1800 rpm on a 3-cylinder Yanmar diesel. Works. It's in a soundbox, so impeller and zinc changes not as easy as they could be otherwise.


-Chris

Westerbeke 8kw. 30 years old. Poor maintenance issues from prior owners due to poor access led to some overheating shutdowns.... but runs well now. A bit noisy with the old sound shield missing some material. The coolant recovery hose fitting at the filler neck needs periodic cleaning out. All in all, happy with it.

Northern Lights is considered the Cadillac of marine generators. Fischer-Panda is considered the Yugo (although not in price!!!, so maybe like the pre Ford Jaguars.). Virtually any 1,800 rpm generator is better than any 3,600 rpm generator.

David

I have an Entec West 4.1 kW genny. It was a near new unit (40 hours) when we bought the boat. The water pump is a March 115 V AC, powered by the genny so it take a few seconds to come on. The pump sometimes loses prime and on starting so you have to keep an eye on the exhaust on startup to ensure the pump is working and get the pump primed if it isn't. Otherwise the unit works fine. I've got about 200 hours on it.


Jim
Sent from my iPad using Trawler Forum

JDCAVE said:

I have an Entec West 4.1 kW genny. It was a near new unit (40 hours) when we bought the boat. The water pump is a March 115 V AC, powered by the genny so it take a few seconds to come on. The pump sometimes loses prime and on starting so you have to keep an eye on the exhaust on startup to ensure the pump is working and get the pump primed if it isn't. Otherwise the unit works fine...

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I believe your AC water pump is a modification, not factory. This mod is fairly common on marine generators. The factory pump is removed and then an endplate is installed in its place. An AC pump is then plumped in and wired to the AC on the generator. When the generator starts, it powers the pump. Placement of the AC pump should be below the water line since they are not self priming. I've seen checks valves installed so the generators don't loose their prime. Some generators have a 3 way valve installed right after the pump to bleed the air/prime if it gets air locked.

Larry M said:

I believe your AC water pump is a modification, not factory. This mod is fairly common on marine generators. The factory pump is removed and then an endplate is installed in its place. An AC pump is then plumped in and wired to the AC on the generator. When the generator starts, it powers the pump. Placement of the AC pump should be below the water line since they are not self priming. I've seen checks valves installed so the generators don't loose their prime. Some generators have a 3 way valve installed right after the pump to bleed the air/prime if it gets air locked.

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Chuckle! Yup! Managed to break the check valve last summer! Managed to put another one on without too much trouble but I spent 4 days in Pender Harbour resolving the problem.

Broken check valve

New check valve.



Jim
Sent from my iPad using Trawler Forum

We have a 12kw NL, a little small for our needs but we make it work. It's amazing how quiet it is, you'd think it was an air conditioner running if you didn't know. We have the Gen Sep.

Regarding smallish older gennies, 4-15kw:

Onan MDJ series- actually an Onan engine. Very old, noisy, durable
Onan MDKC, MDKD, Kubota, very good machines, control system tough to troubleshoot
Westerbeke BTD, Mitsubishi, simple controls, weak electrical ends
Northern Lights, Shibaura engine, simple controls, good machines.
Kohler, Yanmar engine, pcb controls can be trouble, but otherwise very good
Panda- Avoid.

Nextgen, phasor, norpro etc, use various Japanese engines, smaller market share brands, tend to use simple controls and industrial gens- don't overlook these as they have proven to be very good.

Avoid ANY that spin at 3600rpm.

Three cylinder 1800rpm units the best in this kW range.

Not a Northern Lights fanboy here. I have a 5kW in my rig, but I inherited from a repair job. It has been good, but has required a valve job. The quality is good, but it is really no better than Onan and the smaller brand packagers, see below. I don't think the price premium is worth it.

Newer units with computer controls tend to be trouble. No need for a computer to run your gennie, and if it screws up it is not field fixable without parts. And can be a devil to troubleshoot.

While the newer Onans do have computer controls, they seem to have done a better job than most. Most of the failures I have seen on their system have been due to lightning or getting wet. Lots of them out there with lots of use and no trouble. Some Onans are 3600, avoid those. But the late model MDK series, even with computer are good machines.

Extremely rare to see an electrical end failure on an Onan MDK or MDL series that run at 1800. The 3600 MDK's have had many failures.

I have a 20yr old Onan MDKD 8kw in my shop as a hurricane gennie. I took it out of a Bertram where it was salted under the cockpit deck. Rusty mess. Fixed it so it would run. Stator is so rusted you can stick you hand through a hole in the bottom!!! Dang thing still makes good power. That is a good electrical end.

If I was buying a new gen in the 6-10kW range, I would be shopping seriously at Phasor, Nextgen, Norpro and the like. Onan or NL if you can get a good price.

Dead gennies paid for the construction of my boat, so have some experience with these.

Have a new-ish NL 8kw and its really nice. Extremely quiet, no vibration and pretty easy to get at the maintenance points. Haven't had a bit of trouble with it, but it only has 250hrs.

Ken

N4712 said:

We have the Gen Sep.

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Having never owned a generator and just going by what I read and hear, I'll bite! What's a Gen Sep?

Gen sep is a muffler like thing that separates the water from the wet exhaust flow. So the water is ducted to a below WL through hull, and moist exhaust, without much water is vented overboard. Gets rid of the whoosh whoosh noise of water being ejected out the tailpipe.

I guess we have the smallest generator on this thread so far... NextGen 3.5kW. Starts/runs like a champ, low rpm, very compact, can only hear the gurgle of exhaust when running on the outside. Not too loud inside the boat, but we don't have a full sound enclosure. Just the sides and top. But I never worry about it running too hot in the ER. Meets 90% of our needs, but sometimes wish we had the 5kW NextGen.

Darren:

I too have the 3.5 KW NextGen which runs everything I need to on my boat, just not all at the same time ;-). But its noise is not a benign burble; more like an annoying (to boats anchored behind me) putt, putt. What kind of a muffler do you have?

David