Generator overheating

[skydivemark]

My thoughts are vaporlock, I've been told by cummins/Onan tech rep that the 4ky is good at running in hot temps. I had a similar issue so I added a second fuel pump back near the fuel tank - problem solved.

Mounted the additional fuel pump to the inside of the chassis frame a few feet forward of the rear axle.
Also added a vent to help get cooler air from outside.

 

[steveblonde]

Air flow, air flow,air flow
I have a 2020 onan 5500 on my toy hauler this last weekend at about 95degrees and running 2 ac units for about 45 mins ut shut off and blowing codes it only has 70 hrs on it. It smelled hot.

I let it cool, cleared the codes, opened up the cabinet door (its in the front of my 5th wheel) fired it up and ran 3 ac units on high. No issues, it breaths from the bottom but the cabinet gets too hot. Open the cabinet door and my problem was solved

 

[skydivemark]

Air flow, air flow,air flow
I have a 2020 onan 5500 on my toy hauler this last weekend at about 95degrees and running 2 ac units for about 45 mins ut shut off and blowing codes it only has 70 hrs on it. It smelled hot.

I let it cool, cleared the codes, opened up the cabinet door (its in the front of my 5th wheel) fired it up and ran 3 ac units on high. No issues, it breaths from the bottom but the cabinet gets too hot. Open the cabinet door and my problem was solved

I've heard others say things very similar. Leaving the compartment open helps a lot for cooling. Just be sure to leave the gen-set covers installed, they direct cooling air where it needs to go.

 

[crawford 111]

My 5500 in my coach has never been a problem been running full synthetic oil in mine plus it has a fan which come on I'm guessing at preset setting the fan is about a foot in dia. so a good size but do ask me if I ever seen it running answer is no.

 

[udidwht]

Mounted the additional fuel pump to the inside of the chassis frame a few feet forward of the rear axle.
Also added a vent to help get cooler air from outside.

Where did you purchase the compartment air inlet?

 

[sajesak]

First I need to get our Cummins generator running again after purchasing 2 new auxiliary house batteries. We took a road trip from Tennessee to California back in 2016 and I believe had overheating issues on this generator so we could not run the rooftop A/C and my family was burning up. We got out of hot climates into California and it would be good to go since it was under 100 degrees. Then we left to come home, soon as the thermometer on the dash popped 100 degrees, the generator shut down again. I've had people tell me "just drive up north more".... seriously? I see motorhomes driving in the summer months with 2 rooftop A/C's and parents have one that runs in hotter weather with no problems. Is it just this brand or model or do others seems to have overheating problems with their generators too? Yes the maintenance has been completed before that road trip and other times. If somebody else suggest a different generator that is monstrous power and doesn't act like a whiny B, let me know please and thank you.
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JRM1776
Tennessee

1950 Chris Craft Utility converted to 12 volt components this past winter and Spring. What could cause the generator to heat up and melt some wiring? The guy who rewired it said the cause could be a bad cell in the battery (new battery) or bad ground. Hmmm. Prior to the meltdown, the boat started fine. No sign of battery failure. I had no clue if there was a problem with the charging circuit.

In any case, it was odd how it happened. My mechanic friend was over trying to get the engine to accelerate to full throttle, which he did (apparently the carb jet was in the wrong place (hmmm, nobody I know touched it. (Do those move during running?). We ran it up to full throttle with good smooth acceleration a few times. However, during this process at the high end of acceleration it would suddenly pop out of gear. So the next thing was to check the linkage. He wanted to check how it would run if he separated the linkage so he could put it into gear manually without using the shifter. He wasn't so successful at that so he reconnected the linkage, and when we tried again the battery seemed suddently dead (clicking noise). Wasn't the generator supposed to be working charging the battery? Then we smelled the melting wire, and the generator and and can on its side were blazing hot!

I presumed the generator was working before this. The engine always cranked into action everytime I turned the key. We've put only about 4-5 hours on the 12-volt components and battery running the boat at low RPMs (up to 750 because above that it got sporadic, for unknown reasons). Yes, the bilge ran quite a bit over the past 4 weeks of rain. But enough to run the battery down, with us running the boat for an hour or so every couple of days?

The next day, I hooked up another battery and the starter jumped into action. So the starter didn't get damaged, but now I don't know how to check the condition of the generator other than taking it off and sending it back to the guy who rebuilt it.

 

[udidwht]

Air flow, air flow,air flow
I have a 2020 onan 5500 on my toy hauler this last weekend at about 95degrees and running 2 ac units for about 45 mins ut shut off and blowing codes it only has 70 hrs on it. It smelled hot.

I let it cool, cleared the codes, opened up the cabinet door (its in the front of my 5th wheel) fired it up and ran 3 ac units on high. No issues, it breaths from the bottom but the cabinet gets too hot. Open the cabinet door and my problem was solved

Hot exhaust air is expelled underneath then it is trapped there Hot air rises). The generator then recirculates that HOT expelled air back into the cooling stream and this leads to an overheat condition.