Marinette Boat Forum

Folks,

I'm gong to replace my Onan 6.5Kw '88 genny with a used unit. I've read pro's and con's on both Westerbeke and Kohler gennies. I would like you to weigh in on which you feel is better than the other (put a little more emphasis on owners than other boaters... ). I've located 2 units: a Kohler 7.3E and a Westerbeke 8.5Kw unit.
Particulars:
Kohler - 7.3 Kw | 3600RPM | 2005-2008 year model(?) | Gas | Shop rebuilt | Comes with wiring control harness | Florida shop(sea water? possible corrosion issue) | $4k.
Westerbeke - 8.5 Kw | 1800RPM | 89-98 year model | Gas Shop rebuilt | Comes with wiring control harness |Arizon shop - proprietor states that units he buys / repairs come from non-sea water areas/lakes/rivers - corrosion less of an issue | $5k.

Thoughts? Comments? Whatever...

Bill

Bill is their a reasion you need that big of generator! In a 32. I run a 3k westerbeke . It will handle what you can run on a single 30 amp shore power cord. I beleve I met you in madision last year. Joe I think a 4.5 or 5 k would be max you could ever need.

Not that I know much about generators, but wouldn't a bigger one run slower so it would be quieter?

Joe,

I added up the total electrical load of all AC current devices and it came to about 4900 watts. When you take into account the air conditioning kicking in and the higher wattage draw to get it started, that comes close to 6kw. So our current 6.5 kw unit would make it with a little room to spare. It's likely that the load could be significant all at one time:
- Air kicking on/running (w/ the separate AC pump running to feed the air conditioner)
- Admiral in the head taking a shower (1000w water heater reheating water) + drying her hair with a 1000W hair dryer
- I'm cooking breakfast on a 2 burner electric stove
- Coffee cooking in the coffee pot.
- wall mounted oscillating fan distributing the air between the salon and the dinette/galley.

Rockit,
Actually, it's a matter of manufacturer. From my experience and what I've read (ad nauseum... ) some makes (say in the 8kw range) are 3600 RPM (noisier, more fuel usage) while other makes (Westerbeke) are built as 1800 RPM units (more fuel efficient) because of the generating section's construction allows for better efficiency. I've also heard (can't speak to it directly) that 3 cylinder units are a more desirable unit over 2 cylinder (noisey - and this I can attest to from my current Onan <2 banger> and 4 cylinder <slightly more fuel consumption>). But then, that's why I'm asking for input from you folks.

Bill

Bill when I was looking , I was more concerned about weight. The 3 k westerbeke unit weights 165 lbs . How much does that 8k unit weigh. To you have one or two shore power cords. I have one. 30 amp. I normaly run lights, refridgrerator, AC, battery charger,fans amp guage approx 15 amps running . Works fine. If the Admiral wants the water heater, or hair dryer, or microwave she turns the ac off. A 3k unit is small . But I think it is plenty . Joe

Joe,
I made a deal for a 7Kw Westerbeke from a guy in Arizona. Slightly more watts than the Onan that came with the boat. Purchase was after discussion with "Admiral" and concensus that we wanted to have the functionality that we have had since we bought the boat in June 2010.

Pulled the Onan yesterday which was something to watch. I'd figured we needed a sliding track system to lift the genny out of the bilge and then roll out to the cockpit. My son-in-law's brother helped and he thought he and another stout guy could just lift it out of the bilge by hand. Didn't quite go the way he thot. So we used my "Rube Goldberg" contraption which was an 8' section of barn door rail rated at 600lbs attached to a 12' 4x4 and supported at both ends with wood pinned verticle support 4x4's. Used a Tractor Supply 2 ton hand pull cable come along to lift it. Worked pretty slick. After that we went with "4 guys and a lot of grunting" lifting from the cockpit deck, onto the side gunnel/wood boarding steps-platform I'd built, and then down to a 4 wheel dolly. And no pulled backs or muscles!

Bill

On my 1974 32' FB Sedan Marinette the old Kolher Genny sat between the engines. Areal pain in the knees and else were to work on the engines or Genny, but I didn't see any place else it could have been placed because of the 100 gallon fuel tank that sat across the back of the engines. I did think about replacing the single tank with two tanks mounted on the port and starboard side. I solved the problem by selling the boat and buying my 37'
bill

Bill , jumping way to late I suppose . Keep in mind I have a gantry that I built for the engine swap . You are always welcome to borrow it , sits in the barn , here in Cin. As long as we don't drop a bolt or something ....

Bill / Alumination...
I'd like to have solved my dilema the way you did....
... just haven't won the lottery to buy the 41' Marquis I've been droolin' over.

Barefoot...
Thanks for the offer! I may take you up on it when the new(er) genny is delivered.

Bill

I have wired up a circuit that drops some ac loads when other loads come on. For instance, my water heater shuts off automatically when the stove or microwave come on, and so forth. I did this because my dockside power is limited and I don't like to pull too much power from the dock. I did this by wiring an ac current sensor to a solid state relay so that the relay turns off when the current sensor senses that something else has been turned on.

The idea is to limit the maximum current that can be drawn, without having to nag people about what they are turning on. And it keeps me from overloading the system inadvertently. It will come in handy when I finally install more solar cells and get an inverter.

It might also be useful for someone installing a generator: If you can use a smaller generator it would certainly pay for itself.

If anyone is interested in this sort of thing, I would be happy to pull together a how-to on it.