Onan 7000 Generator problems

[Sean Marconette]

Thanks Rich,

I will look into making sure no obstructions, and no nests or rags too.

Sean

[Rich Biebel]

This model Onan does NOT have a high temp shutdown. If they shutdown or won't restart it is not because of any specific safety shutdown built into the machine. It's more like the machine just got too hot and something fails to operate because of the heat.

And yes they do need to NOT suck up their own hot exhausted air.

They had some of these units mounted under the back end of work Vans. They released an air deflector to direct the hotter air away from the front of the machine....I installed a few.

Most larger machines and diesels DO have an over temp shutdown. These would be liquid cooled and have a coolant sensor....

Big generators all have safetys as we call them. L.O.P. Overspeed, Over Temp and more.......all to protect a big dollar unit....

W

[Sean Marconette]

Dennis and Rich,

There is not a divider or ducting, so chances are it is recirculating the same heated air, and just heat soaking everything. It looks like when the trailer was built they just windowed a hole under the generator in the plywood. I found info on the web about the ducting kit that was being installed. So definitely a trip under the trailer is in order to rule out what you guys have pointed out here.

I really appreciate the advice and help.

Sean

[Sean Marconette]

Checked for rags, nests in the fan. It is clear. With it running, it was definitely recirculating it's own air. Installed baffle to correct. Shut it off and same thing. Code 37. Pulled control module and heat sink was very dirty. Cleaned heat sink and reassembled and still code 37. Looks like the module is bad. Probably too many overheating cycles on it. All wiring connections clean and tight too.

Sean

[Rich Biebel]

Part # 300-5047 You can expect to pay over **500 for one.

I have had them fail and can push on the lower right corner of the potting material...... and they work.....

The fuel pump/carb solinoid circuit fails.....usually....

I keep a known good used one around for testing.....

All it is is a PC Board.....in a tray.

The same part number is used for carb'ed models or EFI models.....

[Sean Marconette]

Thanks Rich I ordered one and it should be here in a couple of days.

Sean

[Sean Marconette]

Resurrecting an old post before we had a separate Generator section.

Well same problem different year and several hundred hours later we are back to a unreliable generator. Here is what has been done since 2012.
New module, new fuel pump.

A couple of weeks ago the same no restart until it would completely cool back down to ambient temperature. So I replaced fuel filters, drained gas tank and verified no obstructions in outlet (gas tank is fabricated out of steel and is under trailer) replaced spark plugs with factory NGK and gaped .028". Re-inspected cooling fan for obstructions. Added more ducting under trailer, as air being exhausted for cooling could be recirculated depending on which way the wind is blowing. The generator cooling intake and exhaust are separated by the trailer floor joists. So I have closed off the bottom side of the exhaust with aluminum to direct the hot air to the opposite side of the trailer.

The generator runs fine until it is shut off and will not restart, until it's back to ambient temp. Same code 37. This weekend at Topeka, I made the mistake of shutting off when we left the track to go eat, came back a couple hrs later and it would not run. Starts runs a few seconds and shuts down. Cylinder heads ambient but where the module resides is still warm. We run the generator with the door open in the trailer, and the outside door open to access the generator compartment, we even have a fan that is used to cool the car blowing on it to blow air across it from inside.

Friday morning it restarted at 7 am ran until 2:30 PM when it was 100 deg ambient. Removed access cover and let it cool. It would not restart until Saturday morning and I ran it with the access door removed all day, but it was only in the upper 80's. We are the 3rd owner of this trailer and when we bought it the generator only had less than 90 hrs on it. Now we have 770 hrs. I am running out of ideas to try, as it is so unreliable. It's hard to concentrate on what we are doing at the track not knowing if this thing is going to shut off. It's not running out of fuel as I top off the tank throughout the day because of the no restart issue.

Another idea is to relocate the module outside of the generator housing and install a cooling fan on it, as this is obviously where the issue is. What am I missing on this thing? Do the modules not last that long?

Help!!!!

Thanks
Sean