So here is (it seems) the epilogue...

[SamFisher]

So here is (it seems) the epilogue to the generator saga. My 2015 350 SD has a Koehler 5EKD. The generator specialist informed me they discontinued this model after a judge ruled against them as they apparently reverse engineered this model and told them to halt production hence few spare parts. He replaced the low pressure fuel pump, the high pressure fuel pump, spark plugs and followed the fuel to the choke point which in this case was the injector. Turns out the AF error code on the cabin pad was not the same code (uf,vf) as on the actual generator. When he started it it wan fine on every start and did not cycle rpms like it did before. I guess at the end of the day it was the ethanol. 

[Admiral_Purrl]

WHAT??? We have a 2014 330 and same unit. Have had numerous problems with it. Interesting on the reverse engineering... first mechanic that worked on it said something was backwards. We have pretty much rebuilt the thing. have spend thousands... What issues have you had with yours?

[SamFisher]

There seem to be three basic problems… The first is the interaction between the generator and the carbon monoxide sensor in the cabin ..fireboy makes a variety of units and you have to get the one that is exactly right for the generator or the system will not start due to com errors between the two units… The second is a poor diagnostic system where the error codes are vague and do not pinpoint the exact problem which makes it much more difficult for the repair tech and third and probably most important is ethanol. I purchased my boat with very few engine hours on it but it had been sitting for quite a while and I’m guessing no stabilizer was added to the gas that remained in the generator. I would suggest regardless of who wins arises your boat that you add some stabilizer just before you bring it back to the marina when the season is over. I am not sure where your home port is I am close to the Long Island sound and I have an excellent generator specialist who is now very very well-versed with regard to the 5EKD…

[Admiral_Purrl]

Our CO unit died 3 years into the supposed 5 year lifespan (we purchased our 330 new) but I got lucky by contacting Fireboy directly and we were able to get one of the last remaining units that was the same as the original so it was a swap but wiring it was a fiasco. When that one dies we will have to pay to have it replaced because it does have to be connected to the gen somehow and that's above my husband's comfort level. We use fuel additive when we fill tanks most times so we've been on top of that from the beginning. We also add the Stabil to our last fill up before sending in Winterization orders. We have had a chronic overheating issue. Recently had a problem with air gap but have been able to bleed the system to fix that. Changing the impeller is a 2 hour process as it's not very accessible. Our O2 or whatever is part of the catalytic converter died early as well but we were able to get that part and the tool needed to replace it. As I said we have practically rebuilt the thing over the past 8 years.

[SamFisher]

Had same issue with O2…like your handle…my wife is also an admiral and I but a lowly captain 🤣until the spring…