Diesel Genset in a gas boat

[HawkX66]

I found an 2006 8kw Kohler Marine generator. My boat came factory with a generator so all the plumbing and wiring is still there.
Besides the obvious fuel tank issue, what other kinds of issues could I be looking at?
I like the idea of a diesel much more than a gas for a lot of reasons. The inconveniences of a second fuel are worth it imo.

 

[Chris-380]

A friend had this setup in a formula. Worked really good, the fuel use was amazingly low and his wife felt better about sleeping with the genny running in the hot months of the summer

 

[HawkX66]

A friend had this setup in a formula. Worked really good, the fuel use was amazingly low and his wife felt better about sleeping with the genny running in the hot months of the summer

Thanks Chris. The low fuel consumption and CO of a diesel are definitely big benefits.

 

[HawkX66]

 

[Chris-380]

It’s a big genny for 29’ do you have the space? The tank my friend had was super small, I was surprised, the genny was a 3.0kw I think in his 33’ formula.... the tank was small and it seemed to like he went a long time on that

 

[HawkX66]

It’s a big genny for 29’ do you have the space? The tank my friend had was super small, I was surprised, the genny was a 3.0kw I think in his 33’ formula.... the tank was like 3 gallons and it seemed like he went a long time in that

Thankfully plenty of space, but for the price I could resell it for triple or more and get a smaller one if necessary.

 

[Chris-380]

For that kind of price, I would jump on it, just for the resale value of the boat

 

[HawkX66]

For that kind of price, I would jump on it, just for the resale value of the boat

I already arranged to buy it. I didn't want to miss it. I couldn't see how I could go wrong. I was bummed someone took the one out if my boat before I bought it.

 

[dtfeld]

A genny that size would burn about .5-.75 g/hr, so to do a weekend with AC would still require a good sized tank. You will need a racor fuel filter setup. The only downside i could think of is these things like to be run near or at full load, so you may be oversized on generator capacity, but having a generator on these is a great addition.

One issue that would arise, you would have to be vigilant when refueling to make sure someone (think teenaged dock hand) doesn't put the wrong fuel in the wrong tank, and a future owner may not want the hassle of 2 fuels.

 

[Garintheair]

I found an 2006 8kw Kohler Marine generator. My boat came factory with a generator so all the plumbing and wiring is still there.
Besides the obvious fuel tank issue, what other kinds of issues could I

I found an 2006 8kw Kohler Marine generator. My boat came factory with a generator so all the plumbing and wiring is still there.
Besides the obvious fuel tank issue, what other kinds of issues could I be looking at?
I like the idea of a diesel much more than a gas for a lot of reasons. The inconveniences of a second fuel are worth it imo.

I have a 1995 290 with twin 4.3's and a 3kw Onan gen set which I believe was added sometime after the boat was built.

My boat has a/c, hot water electric range etc... and the 3kw seems to run these well simultaneously. Other than an 8kw probably being way too over size in capacity, I would be more concerned about weight distribution and handling with this hull. My gen set is on the port side and I think weighs <200 lbs. My hot water tank is starboard along with two group 31 house batteries. There are two heavy lead ballast weights in the engine compartment on the starboard side with an additional two ballast weights in the aft cabin starboard storage compartment. Even with these my boat feels stern heavy and lists slightly to port...

 

[HawkX66]

A genny that size would burn about .5-.75 g/hr, so to do a weekend with AC would still require a good sized tank. You will need a racor fuel filter setup. The only downside i could think of is these things like to be run near or at full load, so you may be oversized on generator capacity, but having a generator on these is a great addition.

One issue that would arise, you would have to be vigilant when refueling to make sure someone (think teenaged dock hand) doesn't put the wrong fuel in the wrong tank, and a future owner may not want the hassle of 2 fuels.

Some good points. The manual actually says the GPM is actually a little higher at 25% load and more. The more I read up on on diesel gens, the more I think the benefits outweigh the hassle of two fuels. Sound due to low rpms, longevity etc.
The size is LWH 35"x22.4"x22". I'll have to measure where the original gen sat when it stops raining here...

 

[HawkX66]

I have a 1995 290 with twin 4.3's and a 3kw Onan gen set which I believe was added sometime after the boat was built.

My boat has a/c, hot water electric range etc... and the 3kw seems to run these well simultaneously. Other than an 8kw probably being way too over size in capacity, I would be more concerned about weight distribution and handling with this hull. My gen set is on the port side and I think weighs <200 lbs. My hot water tank is starboard along with two group 31 house batteries. There are two heavy lead ballast weights in the engine compartment on the starboard side with an additional two ballast weights in the aft cabin starboard storage compartment. Even with these my boat feels stern heavy and lists slightly to port...

Sounds like it might be a better idea to flip this one and buy or trade for a smaller one.
Although this one does weigh 200 lbs. Less than me lol
By looking at the water line on the boat when I bought it, it listed to port side. The genset sits on the starboard from the factory. Once a new genny is in place, I suspect it will even out.

 

[CaptRonn]

I put a diesel Phasor genset in my boat this summer, and my boat has 8.1's.

My genset is a 7.0 and burns less than .5 gallons per hour. We installed a 24 gallon plastic fuel tank with a Racor setup, installed a fuel fill and a vent for the tank.

Works extremely well, no problem. For my type of boating the diesel fuel setup works well, a full tank will allow 48 hours of genset run time, and we typically only use during the day for 5 or 6 hours at a time.

 

[b_arrington]

I agree 8kw is big for a 29 ft boat. I had a 6kw in a 34 ft boat driving 3 big AC units, stove, inverter, and microwave.

But that said diesel is a great way to to if you can fit in a fuel tank. By way of comparison, Back Cove has traditionally been fully diesel powered. Their 2 newest boats, the 34o and 39o, are powered by gas outboards. However, they kept the diesel genset and installed a separate 25 gallon fuel tank.

Just consider that Diesel engines do way better then they are run regularly. A good practice is to run the genset whenever the main engine is running. Better to have more hours than less.

 

[hughespat57]

Whoa slow down there!

The phasor diesel is specifically certified as “ignition protected” for use in gasoline powered engine room.

other diesel generators are often NOT
They can have open brushes and other control components that are potential ignition sources if used in a gasoline engineroom

Please check with the genny manufacturer

 

[techmitch]

Whoa slow down there!

The phasor diesel is specifically certified as “ignition protected” for use in gasoline powered engine room.

other diesel generators are often NOT
They can have open brushes and other control components that are potential ignition sources if used in a gasoline engineroom

Please check with the genny manufacturer

Good post. I was wondering about this myself.

 

[dtfeld]

Whoa slow down there!

The phasor diesel is specifically certified as “ignition protected” for use in gasoline powered engine room.

other diesel generators are often NOT
They can have open brushes and other control components that are potential ignition sources if used in a gasoline engineroom

Please check with the genny manufacturer

Thats a VERY good point!!!

One other consideration. Noise. Diesel gensets can be noisy, the sounds coming from 3 main sources. Exhaust, mechanical, and vibration. You'll need to get a good 2 stage muffler and and consider the Gen Sep version. By all means, if you can get a sound sheild...install it, and lastly replace the engine/vibe mounts while its out of the boat.

If your going to flip it, there are some small diesel generators on the market that might be a great fit. Fisher Panda for example.

 

[CaptRonn]

Thats a VERY good point!!!

One other consideration. Noise. Deisel gensets can be noisy, the sounds coming from 3 main sources. Exhaust, mechanical, and vibration. You'll need to get a good 2 stage muffler and and consider the Gen Sep version. By all means, if you can get a sound sheild...install it, and lastly replace the engine/vibe mounts while its out of the boat.

If your going to flip it, there are some small diesel generators on the market that might be a great fit. Fisher Panda for example.

My Phasor is quieter than the gas Westerbeke it replaced. The Westerbeke turned at 3600rpm, while the Phasor turns at 1800rpm. The Phasor also has less vibration.

 

[Garintheair]

Some good points. The manual actually says the GPM is actually a little higher at 25% load and more. The more I read up on on diesel gens, the more I think the benefits outweigh the hassle of two fuels. Sound due to low rpms, longevity etc.
The size is LWH 35"x22.4"x22". I'll have to measure where the original gen sat when it stops raining here...

The gen set in my boat is on the opposite side where the factory states it would have been installed. I also seem to have the larger holding tank on the port side, too, although that sits far forward and doesn't encroach on the area where the generator is installed.

I'm a diesel guy myself and have also entertained installing a diesel gen set in my boat. My 1995 was listed as having diesel engines as a factory option-probably for overseas markets although I've never seen one. I would LOVE to retrofit this boat with those!!

I would prefer an 1800 rpm unit and I haven't been able to find one which meets the space and weight requirements I have. Offset weight seems to be an issue with this particular hull design and size. The Onan that's in there now is very noisy and I would like to change it out for something a little quieter.

 

[Third Edition]

A lot of the newer outboard boats have diesel generators, so it is a growing trend.

The point about the diesel genny being gasoline safe is the biggest hurdle, IMO.