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Gen Runs but Not creating power
Posted: April 22nd, 2024, 7:38 pm
by 650Guy
hey all;
So my 2003 carver 396 with Onan generator was launched. The marina launched it while i was away. When I came to the boat, the Generator was turned off at the generator itself (not the remote start switch at the power panel). I mention this as I have never turned off the generator there so am assuming the staff did this. After rectifying that issue I got the generator to run and it runs perfectly fine, but will NOT provide power at the panel.
it sure seems like there is a breaker popped or fuse blown that I am unaware of. things I have checked:
* at the generator, the field breaker is normal.
* at the generator, the 75 amp breaker is normal
* battery on/off switch is verified ON
* Power panel was triple checked and no voltage or amp pull no mater what I do.
Any thoughts on something I could have missed?
Re: Gen Runs but Not creating power
Posted: April 22nd, 2024, 8:07 pm
by bud37
Heh there , just a guess but try it....reset those breakers on the gen ( off then on ) and start it from inside like normal....if no luck could just be the transfer switch has stuck over the storage period.
Can you normally hear that auto transfer switch clicking after starting the gen or do you have a manual shore/gen switch?
Re: Gen Runs but Not creating power
Posted: April 23rd, 2024, 10:09 pm
by 650Guy
Hey there Bud37! I don't have an autotransfer (2003 that was just too advanced i guess). I have the shore power off, then slide the cover over that side to gain access to the gen breakers, assuring one has to be off for the other to come on.
I think I have switched just about everything I can think of on/off a couple of times, including the 75amp breaker on the unit itself. I have been cruising through the parts manual and found the voltage regulator so maybe that is the issue.
I will be headed back out to the boat on Thurs and think I'm going to test the Voltage Regulator. I have never done that before, so not FULLY sure where to start with THAT. Generators are not my friend.
Re: Gen Runs but Not creating power
Posted: April 24th, 2024, 7:28 am
by Midnightsun
Once you flip over from shore to generator power and the generator is running, is there voltage shown on the volt meter at the main panel?
Re: Gen Runs but Not creating power
Posted: April 24th, 2024, 10:18 am
by km1125
Not sure what model generator that is, but you might have to "reflash" it or replace the capacitor. Either of those will cause a no-voltage condition. The "reflash" problem can happen after long terms of storage, as it causes the residual magnetism on the rotor to dissipate.
Re: Gen Runs but Not creating power
Posted: April 24th, 2024, 12:15 pm
by 650Guy
Minightsun - Once I switch from Short --> Gen the voltage drops to 0 and I do not get the "Green Light" indicating power is available.
KM1125 - I'm not super familiar with a "reflash" or how to test the capacitors. Any chance you could elaborate?
Re: Gen Runs but Not creating power
Posted: April 25th, 2024, 8:43 pm
by Georgeviking
Reflash is not so simple and must be around 50 or 60 volts capacitor is a common one. Before going that route if you are comfortable working on live electric pull the breaker cover off if you don’t have a transfer switch you may have a double pole relay that pulls in when the genny runs that could be stuck or bad if you look at the wiring you may be able to see which is shore power and which is generator
And test it there ,, or pull cover off generator breakers and check for power right at the breaker ( might be the most straight forward ) this way you will know if power made or not, may have indications lights in there also, if no power the cap is next easy one down the line. And don’t have me calling you sparky
Re: Gen Runs but Not creating power
Posted: April 26th, 2024, 3:30 pm
by 650Guy
I got her back!!! So first, I have to thank FlightSystems.com!! if you do not know these guys and you have a generator... SAVE THAT SIGHT!!!! 1 free call to them and all they work on is generators. they can provide maintenance manuals, parts manuals and a wealth of expertise!
So what happened?
1) They told me the generator had to be producing voltage otherwise it would shut itself down. So that was good!
2) They had me remove the front cover on the generator and test the voltage on the breaker(LIke GeorgeViking talked about) I was showing voltage between 6-10 volts. This was just enough to keep the relay closed and the generator running as it clearly saw voltage!
3) I tested the voltage coming in/out of the regulator, and it too was showing 6-10 volts.
with this I was scratching my head and knew I would be making another call to Flight Systems.
So as I put the generator back together, I tried a hail Mary pass. I turned all my AC units off at the breakers, flipped Line 2 to GEN, and then, with the gen running, I increased the voltage with the voltage adjustment screw on the panel of the generator. about 1/4 of a turn, and it jumped from almost nothing to 120v! Tyler at Flight Systems told me to just run it as is and keep an eye on it. as these generators get old and don't have a lot of use, they sometimes will run into stuff like this. They STRONGLY recommend RUNNING YOUR GENERATOR WITH A LOAD as often as you can! He said its better to have a generator that is 5 years old with 5000 hours then 5 years old with 50.
Flight systems has a ton of parts and specializes in rebuilding old parts, but in my case if a voltage regulator was needed, it was $2000! Tyler told me that they could get me a multipurpose unit at a much lower cost that would work the same, just take some modifying to mount it.
so as Paul Harvey used to say (Yes i'm showing my age here) "and now you know the REST of the story"
Re: Gen Runs but Not creating power
Posted: April 26th, 2024, 3:54 pm
by Midnightsun
Awesome information, thanks for posting.

Re: Gen Runs but Not creating power
Posted: April 30th, 2024, 6:34 pm
by JimN
I haven't worked on or with Onan generators, but the shop where I took a friends' Kohler from his '89 Santego 38 told me that the generator should never be started with loads, nor should the switch be thrown to Ship's Power immediately after startup.
YMMV.
Good to see that it's working.