Onan marquis 7000 shutting off after like 15 min/overheat

[Chrisbouch]

I know it's overheating, but this is air cooled a d don't see any blockage in the grate. Is this likely a thermostat?

[FloridaRosebud]

Chrisbouch wrote:
Not getting a code. Maybe it's not overheating you're right. I guess it could be a fuel pump or the exhaust leak. Exhaust leak sounds right honestly as it's hotter than heck and the hot air seems to be blowing as much out of unit as it does out the exhaust and works when cold weather

Do you have a light on the start switch that's on the Genny? That is where you would read the code. The manuals have numerous codes in the back for troubleshooting. It also tells you how to read your code. Mine was a 36, which means the engine shut off with no communications electrically, IOW it had to be a fuel issue. I've learned that the fuel pumps for these gas Onans are good for about 750 hours, then the diaphram gets weak and will not keep the pressure up once it gets hot. It is true for the 4,000, 5,500, and 7,000 gas units. Many You-Tube videos on this issue.

Al

[way2roll]

Chrisbouch wrote:
Not getting a code. Maybe it's not overheating you're right. I guess it could be a fuel pump or the exhaust leak. Exhaust leak sounds right honestly as it's hotter than heck and the hot air seems to be blowing as much out of unit as it does out the exhaust and works when cold weather

If you are sitting still on a hot day and they are running hard it's not uncommon for these gensets to shut down with an overheat code. The genset panel inside would show a code if that happens.

[Chrisbouch]

Not getting a code. Maybe it's not overheating you're right. I guess it could be a fuel pump or the exhaust leak. Exhaust leak sounds right honestly as it's hotter than heck and the hot air seems to be blowing as much out of unit as it does out the exhaust and works when cold weather

[IB853347201]

FloridaRosebud wrote:
How do you know it's overheating? What is the engine code? My 5500 would stop after 15-30 minutes, and it was the fuel pump. How many hours do you have on the Genny?

Al

Mine did the same thing, fuel pump as well. New fuel pump, problem solved.

[FloridaRosebud]

How do you know it's overheating? What is the engine code? My 5500 would stop after 15-30 minutes, and it was the fuel pump. How many hours do you have on the Genny?

Al

[theoldwizard1]

Exhaust leak.

[Chrisbouch]

It's the same gas that's in my Gulfstream, so seems to be doing okay. Not sure the generator model. Does this help model number 7hgjab-9000

[Lwiddis]

Like, could be a number of things. Low oil is probably the culprit. Last oil change by hours is?

[RLS7201]

Which Onan Marquis 7K gas do you have? QG or NHM.

Richard

[MountainAir05]

low oil, sucking air in the gas line.

Put a new gas line on and drop in a fresh gallon of gas.