4BGE Onan heartache

[Austin]

This is my first post.. What a great site this is, I have lots of motors to talk about! I have a generator in the stepvan I drive that I would love to get working, it has the same problem that I keep reading about, not staying running after the starter button is released. I can jumper the fuel pump and coil to the battery and it runs fine but only outputs 2 volts or so instead the 120 ac. I dont know which wires are the exciter wires without taking it all apart, I think its sposta have 18 volts on them to make juice from what I have read. I could make it work without the regulator or whatever that way, but I really wanna figure out how it works so I can fix it the right way. I could solder in more diodes maybe... I dunno.. Would somebody maybe please send me a schematic or something so I can figure out how to test the control board and voltage regulator and figure out how to repair them? Maybe its just hooked up wrong from the last guy who tried to fix it I dunno. But any help would be great, I know this is a common request on a common genset, there ought maybe be a ftp site with the pdf for download I know that would take away from guys trying to sell them on ebay but heh.. My generator says 4BGEFA26100H and my email is DirtyRottenStinkingBiker@yahoo.com and I love the smell of two stroke oil vapor in the morning. Thank You

[richard.bessey]

Have you checked your slip rings yet? Pretty easy to dissassemble and check.

[Austin]

I dont know what slip rings are, I did let it run today and burn a quart of fuel, the brushes in the back of it put off 10 volts dc according to my meter. Sorry Im a n00b.

[K D Redd]

Slip rings are the brass rings on the rotor that the brushes rub on. They need to be clean. The do not need to be totally shiny brass as the carbon of the brushes will discolor them a little. Try cleaning them with some steel wool. Sand paper would work BUT you have to watch and NOT leave any grit behind that could wear the brushes or the slip sings. Also be sure the brushes are loose/ move well in their guides. NOT a Resident Smart Guy but I can get along.

Kent

[Austin]

Thats what I thought slip rings were, I didnt know if there were two sets of em or not. What should the voltage be on em? The rings look pretty shiny and like the brushes are rubbing in the middle of them, after running it hot wired yesterday for 30 mins. I figured it couldnt hurt anything to run it a little bit since it has been sitting so long. Runs smooth, no surging. I guess Im lucky that way at least. It did smoke a little bit at first but then pretty much stopped. Of course that may be from the 32:1 weed eater gas I was running in it. Be good for the valve guides I thought... It has oil in it, is the oil wire sposta be grounded when theres no oil pressure right? So it sposta be open to ground when there is oil pressure right? Would it run unhooked to take that out of the equation? Prolly the last thing to break in order of things to go wrong is the lop circuit I would think. How do I properly measure the brush volts and what should they read? Mine read 10 volts dc brush to brush I think, Ill have to fire it up again to see for sure but is it sposta put out ac? maybe I was reading it on the wrong setting on my meter. Thanks in advance for any help!