1979 Travel Queen ONAN Generator

[Cwatson]

I have 1979 Travel Queen Class A motor home with a ONAN Generator on it! When i first bought the rig it worked great. I have had it serviced regularly! Last year when i was driving it back home from a camping trip, we hit a pretty big pot hole thanks to the great oklahoma roads! The Generator Died and i have not been able to get it to stay running since. I have searched around the forums to no end. I keep coming back to the same similar issues where it will crank and run as long as i hold down the start switch but as soon as i let off it dies. I have taken off the panels and such looking for a LOP sensor and I do not see one where its described by most! I will see if i can find the model number and do some more searching from that but any other ideas at this point?

[dougrainer]

https://ia800907.us.archive.org/BookReader/BookReaderImages.php?zip=/14/items/900-0337_Onan_BF_BFA_B...

This is a link to the troubleshooting for your problem. Doug

[dougrainer]

MrWizard wrote:
Doug is right
It uses a winding in the generator head to act like a starter, spin the generator armature shaft to slow crank the engine for starting
Has points and ignition coil, no CDI,
Thermal choke, and battery charging to keep the generator start battery charged,
Many of these were wired to the chassis battery when installed, not the RV house batteries,
Since they supplied a charge to keep the battery up, they would charge the engine/chassis battery,
And the RV converter would charge the house batteries

The battery charger was a 1.5 amp. You had DC and AC brushes on the very large Armature. DC brushes are what turned the armature and the engine to start the Genset. Once running the AC brushes supplied the AC current. Doug

[MrWizard]

Doug is right
It uses a winding in the generator head to act like a starter, spin the generator armature shaft to slow crank the engine for starting
Has points and ignition coil, no CDI,
Thermal choke, and battery charging to keep the generator start battery charged,
Many of these were wired to the chassis battery when installed, not the RV house batteries,
Since they supplied a charge to keep the battery up, they would charge the engine/chassis battery,
And the RV converter would charge the house batteries

[dougrainer]

ksg5000 wrote:
All the above comments seems reasonable. No generator guru but when you press the starter switch the generator essentially bi-passes the hi tech safety stuff and the generator fires up. When you release the button then all the electronic safety stuff engages. Loose wiring and low oil are the two inexpensive solutions.

Yes, but OLD Onan Gensets do not have "any electronic" control parts at all. They do not even have a electric starter in the type of new Onans or cars. Even the Older CCK Onans, that had electronic control board, it was replaced with the old mechanical systems which is what the OP has. Doug

[ksg5000]

All the above comments seems reasonable. No generator guru but when you press the starter switch the generator essentially bi-passes the hi tech safety stuff and the generator fires up. When you release the button then all the electronic safety stuff engages. Loose wiring and low oil are the two inexpensive solutions.

[Matt_Colie]

Chris,

What ever else happens, if you can't make it work, find a local small engine shop. You don't give any hint what it is, but Onan engines have been installed lots of places for a long time.

Next big hint. If it is a "Power Drawer", then I have another stop for you. These were installed in about 13,000 GMC motorhomes betweem '73 and '79 model years. Both the 4kW(BF) and 6kW(NH) were used. If it is one of these, then root around at the site and you can dig up a wealth of information about these beasts.

While many replace them because they are now old and were mistreated in their youth, many of us elect to just extend the effort to keep them running. It isn't very difficult to do.

Matt

[dougrainer]

The LOP switch is located behind the Metal Cylinder head cover(That has the oil Filter hole) on the front of the Onan. There should be 3 or 4 small bolts that hold that cover ON. Also, inside the square metal box that has the Fuses and Start/Stop switch, you will see 2 square BOSCH relays mounted to the bottom of that box floor. Make sure you do NOT have ants inside those relay's. VERY common for the old Onans to get those ants inside those relay's. You will see dead ants all around those relay's if you have these ants. Doug

[MrWizard]

Disconnect the main 12v power cable for the generator,
Also remove the control fuse for good measure,
Open the control box and check all connectors for being loose and dirty connections, loose wired etc, it sounds like a loss of power to the fuel pump
Also go-to SmokeStack.com
Its a specialty website for old generator, got some members with lots of know how and experience that can be a big help