Genset.... is bigger always better/needed

[NYSail]

hello all,
So into my summer with new boat (beneteau 423). We have 2 air conditioning units, refrig, 2 electric heads and typical systems. We love to be on boat and plan on extensive time away when the house is paid!! Anyway, boat came with a onan 6.5 generator, however electrical back end is shot and needs to be replaced. This according to a major yard here in NE at a cost of 8500 (backed that cost away from negotiated final price!). I am planning on getting two estimates and having it repaired this winter. But if the estimates come in at 8500 to fix an older generator with 250 hours on it, is it worth it? 250 hours on a small Diesel engine seems like lightly used to me..... I could though purchase a new, maybe a bit smaller......
We typically stay on anchor/moorings and are fine without a/c but maybe every now and then especially when south or a little heat in the spring /fall or the quality battery charge- ups when away for extended periods makes sense.... to me at least. I am planning on getting a new smart alt that will better do the job while motoring (80 amp dumb alt is adequate at best) as well as at least 150 w of solar.
So what say people.... never had a generator and always relied on Honda 2000.
Btw current batteries are 420 ah house and 110 ah starter.

Thanks!
Greg

 

[justsomeguy]

Uh, are we talkin' 8,500 dollars?
Buy new and part out/spare the old.

 

[Rich Stidger]

I replaced my back-end of my 5.0 KW Westerbeke myself in under a day. About $2500 for the parts and $800 for the yard to lift out and in.
The answer to your question on size is to choose a size that will run everything that you typically run at the same time. If you don't run both A/Cs and the water heater together, you don't need the capacity to do so. Diesel gensets like to run about 80% of full load.
Do the math.

 

[Mark Maulden]

Whats wrong with it?

 

[Jerry Clark H356 SV Persi]

I have a 5 KW Northern Lights on my Hunter 356, 15 seasons since we bought new, 3,217.5 hours and we run ours continuously when off the dock for heat/air and other AC loads and HWH while at anchor. If I had two HVAC units like you have I would get 6.5 KW for the extra HVAC unit, so I think you are properly sized, but a 5KW would probably handle you well without the other AC running if you decide to replace. Mine runs about .25 gal/hour; 6 gal per day (24 hrs). 250 hours is not much time on a generator.

Once you run a generator while traveling, you will want to run it much more. It shouldn't be thought of as a battery charger as a primary use, but many people think that from the waythey were thought of in the past.

If your engine is ok on the Oman, then I would get pricing to just replace the power components. I agree with Rich.

Even though you don't use it all, if you plan to resell, the next Owner might want to, particularly if the boat makes it's way south via ICW.

 

[SG]

We have a Westerbeke 7.5 KW unit. We have an 200 KW Mastervolt charger (which when it starts up with low batteries is a material load); three AC units; and a water heater.
We have a 50 Amp SINGLE PHASE limit on the generator. I recall we have a 13K 7K and 8K BTU AC Units.

Occasionally it will trip and I have to turn-off the hot water heater if it's loading things up while everything else is running at heavy loads. Otherwise, its fine.
It's been running into its 19th season with a less than 2,100 total hours.

A constant RPM generator should have a duty life which is much longer than a variable RPM/frequency unit (e.g., Pathfinder) would have. You need to keep it in clean oil and filters once a season (for our use). We've had a waterpump replaced once or twice over the years. Ours has it's own initial Racor filter.

What happened to yours that caused the issue?

 

[NYSail]

Not sure about what happened. Previous owner said he used it when he was on boat but his use
Of boat was limited to about 1 week away in the summer and a few weekends and most probably at a slip. He said it worked fine up until the end of
Last season right before I bought the boat. He had an estimate and they said just that electrical back end was shot. With everything else I've been learning about the boat the generator has not been a priority however I do want to plan to have it pulled in the fall and figure out my next step with it. Looks easy to pull
And yard will lend me their lift for basically nothing.
I have two guys that have been recommended to do the work, however if it's a simple replacement I may be able to swing that and save some money. So far this season we have managed no problem without it and just used my honda 2000 when needing a charge. But I do see the benefits for future travels hopefully far south.

 

[Rich Stidger]

NYSail- PM me and I will send you the info on the company that supplied my new backend.

 

[Rick486]

We have a Fischer Panda 6kw with around 800 hrs. On cruise, we use it every day to charge batts and run A/C when needed, and make hot water. it uses about .5 gal/hr. Your Onan with 250 hrs is NOT a throw away. You need to find a competent Onan dealer with a mechanic to repair what you have. My advice is DO NOT succumb to marketing pitches. Onan is owned by Cummins so any Cummins dealer should be able to repair it. FIND OUT WHAT IS WRONG. Does it start?

 

[Terry Cox]

Hi Greg, our 1991 H42 came equipped similar to yours. Main cabin A/C is 16BTU and aft cabin 9. Electric heads, freezer and separate fridge. Original Onan 8kw Genset has a bit over 500 hours and still doing its job. Seems odd that your unit needs major work with only 250 hours. Cummins used a three cylinder Kabota diesel to drive our Genset. Hardly broken in at 500 hours.

It would seem to me a lower cost option to replace/repair electrical system rather than the whole unit. What size/make engine did Cummins use for your Genset?

 

[SG]

He said it worked fine up until the end of [l]ast season right before I bought the boat. He had an estimate and they said just that electrical back end was shot.

The there two principal sections of a simple diesel engine generator (plus the controls): The engine and the generator. ;^)))

If you're saying that the engine works -- it just doesn't produce power, then the rebuild/new parts would be limited to that section?

http://www.twinslan.net/~n0nas/manu... MDKAB Marine Diese Genset Service manual.pdf

 

[seadaddler]

There is nothing like having a built in diesel Gen and just pushing a button and all auto is like the best thing ever.
When I was up on LI AC was not always needed but boy when it got hot it was the best ever,now living in Florida AC is a biggy and much needed for sure.
I do come to L I for July and August and love the fact that I use AC in my RV now and having a Built in Gen is also great and not having to drag out a Gen on my boat or RV is a plus for sure.
I did have a Onan Gen repaired a few years back and it was gas and the repair which had to remove from my RV and was much cheaper than to replace.
Once you have a built in Gen you can't ever go back,the important thing with Gen is you must use them regularly and don't let them shit idle very long and always use with a load either AC or the water heater.
Good luck with your repair.
Nick

 

[SEMPERAVANTI41]

Seams odd to me that the generator end would fail at 250 hours. Exactly how did the yard determine that the generator end is shot? What tests were performed? Did they have an Onan shop manual? Did they follow any troubleshooting guides?
Before I would do anything I would want to know for certain that in fact the generator end is shot and it's not some far less costly repair.

 

[NYSail]

Yes I fully agree.... like I said I have not even attempted to start the generator. Apparently the yard (brewers) had an online certified mechanic come in and look at it. I Just got back from couple weeks on boat and will start to play with it..... like to see if it starts. But will get an estimate from a couple of mechanics and see what they say.

 

[Ken Cross]

250 hours is a new generator.
It's always easier and usually cheaper to fix the one you have. It's not rocket science. Go online and find a maintenance manual. If you do the work yourself, you will be better equipped to know what to do in you have a problem with it in a remote location. More experience = better and safer sailor.

Ken

 

[capta]

If the back end is shot @ 250 hours, it's quite likely the gene was run with too big a load. That's not the easiest thing to do, as this stuff is usually properly designed for any possible, loads by the installer.
We're in the process right now (just pulled the unit from the boat a few hours ago) of replacing the engine and having the generator end cleaned and serviced at around 18,000 hours. It actually still runs pretty well, handling all loads, but it is beginning to be a maintenance headache. Little things like freeze plugs and whatnot giving us problems, which we cannot afford as a charter boat.
I'd advise you get several opinions on your problem, as it just doesn't sound right. Absolutely the most difficult part of owning a boat is finding competent help for repairs and service. Do not just take one or two guys' opinions on a big expenditure like this. Keep bringing people aboard until you find one who can give you an intelligent, in depth explanation that makes sense.
Good luck.

 

[seafox]

2 years ago my Kholer 8EOZ stopped working. Spent about a month researching and troubleshooting . The engine started but quit almost immediately. I am not a great techie and asked around for the best Kholer tech and paid him hourly to diagnose the problem. Took less than an hour vs my one month with no results. As it turned out he identified that the small stationary stator was defective. Kholer wanted $2500 for a new one. Removed the stator and sent it a shop to rewind it. (The tech's suggestion)
Cost me $400.00 to rewind. Installed it and 2 years later still working. As it turns out corrosion had set in the wiring and caused a break from non use by previous owner. It gets a lot of use since I bought the boat.
So far so good!

 

[NYSail]

I do agree! I am now putting my mind towards this.... 250 hours is nothing in terms of use. In regards to overloading doesn't the overload protection built into the unit prevent any damage due to misuse/overload?? First I am going to make sure everything is properly connected, then going to attempt to start unit and will work from there. I have two guys that come recommended plus I have a good friend that is an electronic wiz (not marine, however knows how things work) that is going to help me along and give me his opinion. Thanks to all!!

Love this site....
Greg

 

[SG]

The overload issue over - taxing the diesel engine is unlikely an issue. There are, as was cited above, some control systems that will shut down the generator if it sees a fault on the generator. There are some systems that will shut down the generator if it overheats (usually a water pump or thermostat issue), etc.

I'd suggest that you over the manual I sent for the Onan servicing; or, get the one that actually goes with your unit on-line. form Onan/Cummings. Do that before you hit the "START" button on the generator ;^)))))

 

[Gunni]

What SG said. Every system on your boat should have a service manual and parts list - on the boat. There is definitely a downside to having one more internal combustion engine on boat, you have to understand how it operates and is maintained. Congratulations, you have a new title - Powerplant Operator.