OVERSPEED Onan DJE generator starting problem

Couple of things to check - first is the governor linkage moving as the engine comes up to speed - sceck for free movement. Oil pressure ok?

Yes, it does.

It goes too high, beyond the capacity of the pressure gauge.

That is likely normal, with cold oil. If you could get it to run for a minute or so, it would probably come down. It is also possible the engine has the wrong oil grade in it.

That overspeed button is pretty confusing! But, it may jam the governor to allow maximum fuel flow, and that's why it allows the engine to run. Can you get a ballpark idea of what RPM it is developing when you hold this button? Are both cylinders firing, or is it just running on one?

Jon

After little thought I think the bouncing solenoid is a clue to the problem. Something is stopping it from full travel and the 'hold in' coil is not energizing. Again go over the governor linkages as well as looking at the output lever on the governor. It could well be that the governor is frozen (stuck) internally - that has happened to me. Slap it around a little. It would be seized in the off position and, if the 'overspeed button is designed to allow the engine to ignore the governor, that would give you the symptoms noted. Ken.

The solenoid could be one of several things.... A fuel shut off, A compression release, or a fuel shut down that works on the governor. I can't tell what it is hooked to from the picture. Usually a solenoid makes noise when it has low voltage. Overspeed..... that reminds me of the 6V53 Detroit Diesel that ran away on me and a so called Ace mechanic when he failed to assemble the governor properly. Since then I have made it a practice to have a plate to block off the air intake when playing with engines that might try to wind into the stratosphere. Steve

I am sorry, it is a pain to find stuff in manuals, just where should I look?

I can supply any number of pictures if necessary. What's a good place to look into?

Damn; If I wasn't 8000 miles away from mine I would just toddle down to the shop to refresh my memory. IIRC the governor should be somewhere to the right of the 'buzzing solonoid'.

Just a wild guess... perhaps the Overspeed Button Tests a "run away" condition by forcing the engine to run fast? Then if its working, it would shut down. Like I said, just a thought, so that increase in throttle makes up for "some defect" allowing it to run for a few minutes. 'till you let it go.

meant to say "some defect, like dirty injectors or fuel filter"

The solenoid is connected to the Injector Pump Rack, that is also connected to the Governer Arm that has a spring that is adjustable from the front of the air cooling housing. If the Safety Shutdown System (Oil Pressure, High Engine Temp, Ect) is in shutdown mode the Overspeed Switch is the only way the shutdown solenoid can be activated to allow the Injector Pump Rack in run condition. Go through the circuit diagram of the Safety Shutdown Sytstem and figure out where the problem is. You can also bypass the shutdown solenoid, by unhooking it mechanically from the Injector Pump Rack, and then manually holding the rack to sutoff condition when you want to stop the engine. The speed of the engine is set by the position of the Injector Pump Rack, and can be manually manipulated it you disconnect the governer arm linkage. By watching what happens to the governer arm while you manually change the Injector Pump Rack, you can tell if the geverner is operating correctly. Once that has been established, then it is just a matter of setting the governer arm spring tension, and linkage length to the Injector Pump Rack, to set the engine speed to 1800 RPM, and 60Hz. Most folks set the unloaded speed for 61Hz, which would drop to around

This is all covered in the Operations Manual for DJB's and the DJE is Just a latter version of the DJB. I looked it up and you are right about that.

Bruce in alaska