Generator issues with 31?

Mikep

Well-known member
Joined
Sep 13, 2020
Messages
64
Fluid Motion Model
C-302 C
Vessel Name
Dive In
Been boat shopping over the past few weeks and one common theme I am seeing are rust stains in bilge coming from rust i on the bottom of the generators/ signs of leaking. How reliable are these generators ? What causes the leaks?
 
Our NexGen runs like charm, I did have to increase the breaker fuse from a 30 to 40 amp, per NexGen recommendations. I’ve not seen any rust or have had any water leaks. Tell us what year boat your are referring to, brand of generator so others with similar yr and make can offer there experiences.

Jim
 
I have been looking at 2014 and 2015 on an 5k
 
If this is the Onan, I have done extensive work on my genset due to some water migration.

The bottom line is that this is a great genset. If there are some rust streaks, the cause can be mitigated and any concerns resolved.

I bought my 2017 R31CB with 60 hours on it. I noticed some evidence of rust from the genset. We did everything we could during inspection and survey to reproduce some sort of leak but could not. I ended up suggesting we take $300 off the agreed upon price knowing that eventually I'd have to take care of something.

The rust that I noticed came from the bottom of the sound shield housing. I also noticed some corrosion on the starter, indicating it was coming from somewhere above.

After purchasing the boat and putting well over 100 hours on the genset, I kept noticing a little rust every now and then and a little more corrosion. Eventually the starter and oil sending unit failed due to corrosion (About $300 dollars to replace - my labor to instal). As a bonus, I developed an expertise in working on the genset and art of body contortion.

In the end, I found two suspected areas of water migration. The first, I identified small leaks around the white 6" round access ports on the sole of the cockpit. Interestingly, these leaks were occurring because the access ports are mounted where there is a combination of nonskid and smooth surfaces. When the screws that mount these portholes are tightened down, it slightly contorts its otherwise perfectly shaped sphere. This allows for water migration through the area between the treads and frame of the ports. Water drips right on top of the gentset sound shield, evidently finding its way inside.

Also when taking the engine apart several times, I decided to just check everything for tightness. I was able to tighten all of the hose clamps a bit more, and even cinch the screws on the heat exchange down a bit (I think this might have really been the culprit, but water from above seemed also probable). In either case, problems found and problems solved. No more corrosion, no more rust streaks.

The bottom line is that some rust streaks from the generator should not kill an otherwise good deal and these great boats. As well, I don't think there is a better small generator than these small cummins.

The options you might have once you get down to final purchase, if you have this problem, is to push for the issue to be eradicated (which sometimes is hard to find at the time). Or, come up with a dollar amount that will make you good with the deal, knowing you will probably have to address it at some point in the future. I was good with the deal.

Let me know if you have any more questions.

Best,
Bobby
 
Thanks for the info. We made a deal and are in the process of purchasing a 2014 31S. No rust stains on this one..owner looks to have done all the right stuff and hope survey to come out clean. I will share your info with the surveyor.
 
I think due diligence is often overlooked when it comes to the generator on a “general” survey. Often a separate survey is done of engine(s) that is far more exploratory. At a minimum, get the top and front soundshields off and shine a light on the starter so that you can identify if there is any corrosion. Good luck!
Bobby
 
I think due diligence is often overlooked when it comes to the generator on a “general” survey. Often a separate survey is done of engine(s) that is far more exploratory. At a minimum, get the top and front soundshields off and shine a light on the starter so that you can identify if there is any corrosion. Good luck!
Bobby
It seems I have found someone with experience with the Onan genset and hoping you might have some insight to my issue…. It won’t start, just getting a click then nothing. I jumped the starter to see if that as the issue, but that checked out I.e., the engine cranked but still didn’t start. The 2 relays controlling the starter and the glow plugs/ fuel pump also checkout. I’m measuring 13 volts at the relays, so power is getting to the relays. I am going to test to see if there is voltage on the wire going to the ‘S’ terminal on the solenoid/starter, but need a second pair of hands to push the start toggle. I expect that I will not see any voltage, which means the fault is between the relay and the S terminal. What can I test next? Any thoughts are appreciated

Steve
2016 Cutwater 30 CB
 
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