Running Genny Underway?

BlewByYou88

BlewByYou88

Member
Jul 24, 2010
963
Arizona
Boat Info
268 Sea Ray Sundancer 1988
Engines
2X 4.3L 4bbl Mercs w/ Alphas
I feel this is something I should know, but I haven't found any information on it. With this type of "pick-Up" can I run my genny while underway? I checked a few threads, but didn't find anything I was looking for, and the manual doesn't say weather nor not I can either. I'm surprised with all the genny questions we don't have a dedicated forum for them.

DSCN0655.jpg

Any Thoughts????????:huh:
 
I had to go to my manual to look. It says to start the genny before getting underway, due to the possibility that it may not pick up water while underway, and that's all it says. My dealer said not to as that it may loose water pickup due to air under the boat. I guess that leaves you with a risk of it overheating due to the loss of water. I'm not sure I'd risk it, a genny runs about 8500.0 to replace.
 
BlewByYou88 said:
I feel this is something I should know, but I haven't found any information on it. With this type of "pick-Up" can I run my genny while underway? I checked a few threads, but didn't find anything I was looking for, and the manual doesn't say weather nor not I can either. I'm surprised with all the genny questions we don't have a dedicated forum for them.

View attachment 25809

Any Thoughts????????:huh:
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Are you sure that this scoop strainer is for the genny and not for the A/C? It should be for A/C while one for genny should be like mushroom looking strainer. Anyway, generators are designed to run while underway. But, as said above, don't attempt to start the genny when running on plane.
 
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What you are showing is called a "Speed Scoop". When aligned to the direction of travel, it applies a positive pressure (variable, based on speed) to the generator. In theory, it sounds like a good idea, but, it can have a catastrophic result. Here is the explanation per Kohler Bulletin No. 90-IAN:
"When the generator is not running and the vessel is underway, the pressure that is induced to the sea water pump varies; however, a sea trial has shown with as little as 14-inch water column or .5 psi the sea water pump impellor will deflect. When this happens the sea water will trickle /flow (depending on pressure) through the heat exchanger, exhaust mixer, and ultimately stop at the engine silencer. At that point, water backs up through the engine exhaust resulting in flooding the engine and vessel. In order for the water to be discharged out of the muffler, the engine must be the driving force. In other words, it must be running. Exhaust pressure is what forces the water through the silencer."

There is also a concave device called a "Sea Chest" which for the same reasons is unacceptable.

What Kohler shows as an acceptable inlet, is a flat, oval shaped fixture with holes or slots.

The Bulletin that I am quoting from is not dated, but, appears to be pretty old (perhaps 1990). You may want to contact Kohler or marine generator repair shop to see if you can obtain a current bulletin or guideline concerning "Speed Scoops" and "Sea Chests".
 
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BTW, that may be as Alex says, your pickup for the AC unit. The pickup for my generator is the flat oval shaped strainer/pickup and I do run the generator while on plane.
 
I have the same scoop on my genny, quiksilver 5k, and have run it under way many times without failure. I do however do not run it under way anything over 15 - 20 mph. I've done this with only after consulting with boater friends with many years exp.

Sent from my PG86100 using Tapatalk 2
 
Thats a negative on the A/C Pick Up Gents. I have the exact same pickup for both the genny and the A/C both mirrioring each other from Port to Starboard. Then there is a big brass strainer inside the engine compartment from each pick up. This is the factory design that Sea Ray put on the boat, and the Genny hasn't had a water ingestion issue in over 24 Years. Its the original Cast Iron Onan MAJB 3.0kW that Cummins now likes to call my "Antique" They told me that even though unbearbly noisy, she'll probably run forever and will outlast even some of the best, newer generators. And this genny has no exchanger....completley raw water cooling.
 
Also note, those scoops face AFT, not foward. SO the only positive pressure would be through the little hole oposite of the grates.
 
I ran the 3kw Onan on my 290 underway for almost 5 seasons. I run my current 7.3kw Kohler underway also.
 
BlewByYou88 said:
Also note, those scoops face AFT, not foward. SO the only positive pressure would be through the little hole oposite of the grates.
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Aha.....this is the trick that's used during the installation. So, I guess they used scoop for genny as well to have some guard against underwater objects making their way to the unit. Anyway, it's no big deal. Use your genny either underway or stationary. The main thing is not to attempt to fire it up while on plane. When I'm on a long trip and need to fire up the genny, I would come off plane to idle speed, fire it up and then jump back on plane.
 
My Honda EU2000i starts fine while on plane.
 
Quint4 said:
My Honda EU2000i starts fine while on plane.
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Hijack!!! Thanks for the cup holder idea, btw Quint!!! One of my favorite add ons!


Shaun
Sent from my iPhone
 
My Gen runs the entire time i'm not on shore power. on plane, off plane, up north, at anchor.
 
I fire my genny up before I disconnect my shore power and shut it off when I'm at my destination hooked up to their shore power. No problems!!
 
No problems here either; my generator runs fine while I'm on plane!
 
Quint4 said:
My Honda EU2000i starts fine while on plane.
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LMAO...LOVE IT!:smt038

Thanks for the info guys, I will give it a shot. I didn't think it would be a big deal, but I have never....ever done it in the past, and I'm going to be needing some serious A/C tomorrow. PLus, all the over heat, and oil protections still work on it, so if it does start to overheat she'll shut down.
 
Quint4 said:
My Honda EU2000i starts fine while on plane.
Click to expand...

Just make sure you use two bungy cords to tie it to the swim platform so it doesn't fall off.
 
Spent a fortnight on the brother in laws Riveria 58. It has 2 genny's, a 10kva &a 20kva, basically depending what load is required is what genny is running, and one was running all the time including about a 460nm sea voyage.

I would have no concerns running my 5kva Koehler on the 330 Sundancer.

If concerned I would keep an eye on temp guage and check the coolant output to make sure that it is flowing through


Sent from my iPad using Tapatalk
 
Quint4 said:
My Honda EU2000i starts fine while on plane.
Click to expand...

Westie said:
Just make sure you use two bungy cords to tie it to the swim platform so it doesn't fall off.
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I would NEVER risk my families comfort so recklessly!!!






I would keep my Honda in the bilge where it cannot be stolen so easily! :wow:

MM
 
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