OVERSPEED Onan DJE generator starting problem

Okay, I got a lot of things going better, and am stuck with
something.
The starter works beautifully, so do glow plugs.
There is a white OVERSPEED button on the engine, whose purpose is
unclear to me.
The engine would start any time I would depress the OVERSPEED
button. It runs for as long as I press the button, producing menacing
diesely sounds and white smoke. As soon as I release the OVERSPEED
button, the engine stops.
My supposition is that the overspeed button is linked to the
governor/flyballs etc, and is designed to act to stop the engine if it
detects overspeeding. For some reason, I suspect, this system is not
working properly and engages when it should not engage. Maybe
something is simply stuck from decades in storage and need to be
unstuck. (like the "governor arm" or whatever.
I also suspect that it was related to the rattling noise coming from
solenoid pictured here:
formatting link

This rattling noise occurred when I pressed the start button and at
the time when my starter was not actuating. (it cannot be heard when
the starter actuates because the starter is louder)
Any thoughts? This does not sound normal and I would not let my engine
run for more than 15-20 seconds. Not even enough time to test the
genset with a voltmeter and a kill-a-watt.
i
Reply to
Ignoramus7135
Loading thread data ...
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?
Reply to
Ken Davey
Yes, it does.
It goes too high, beyond the capacity of the pressure gauge.
i
Reply to
Ignoramus7135
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
Reply to
Jon Elson
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.
Reply to
Ken Davey
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
Reply to
Steve Peterson
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?
i
Reply to
Ignoramus7135
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'.
Reply to
Ken Davey
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.
Reply to
Forger
meant to say "some defect, like dirty injectors or fuel filter"
Reply to
Forger
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 59Hz a full load.
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
Reply to
Bruce in Alaska

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.