Onan 7000 Generator problems

[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

[Rich Biebel]

Sean, trust me here when I tell you I feel your pain but in this case I have no magic bullets for you. The modules or PC's generally are the reason for high temp shutdowns and if you changed it I would not expect it to be the problem so soon...but here are some things to try...

If the machine gets hot and won't restart....try closing the choke right at the carb while cranking it at the machines switch. These machines are very difficult to restart hot most of the time. If you choke it momentarily they starrt right back up.....Very old style bi-metal spring style electric choke with a vacuum break or pulloff.....

There is a small 2 pin connector on the solenoid at the bottom of the carbs float bowl. 12 volt supply allows fuel to pass thru the carbs main jet....That is the circuit that fails on the PC board. It is the same circuit as the fuel pump. If you can clip a meter to the solenoid leads you can look for 12 volts + and - there anytime you try to start it or with it running. If that voltage is lost it will shut right down. There is also an ATK type fuse for the fuel pump and the connector or wires might be poor....check it.

The machine MUST have a good battery connection both + and - and the + post sometimes gets loose....it is double nutted.....check it. The small white wires power the PC board......

Code 37 is not a normal fault code I see on those....36 yes.....Possibly you misread the blinks? Code 36 points to a loss of fuel......or a shutdown without a command.......Yea I know we already know that....!!!

I have a pretty large contingent of customers that have these units in mobile dog groomer vans......I have seen most everything but they throw me some curves sometimes and I just work to resolve the issues as quickly as I can.....

[Sean Marconette]

Thanks Rich,
It is code 37, as I read it several times and had my wife double check me. All I find for code 37 is " invalid genset configuration fault". I may not have described won't restart very well. It will start and shut back down within 5-10 seconds. I will check the fuel solenoid and see if it is the issue. I have pulled the 12 VDC power and grounds and verified those connections.

Thank you for your help.

Sean