bounder39zman
Explorer II
Joined Mar 19, 2014
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Re: Cleaning Onan generator slip rings
I have used the "Slick Stick" a bunch. worn a couple out. If the slip rings are only slightly oxidized/worn you can clean them. I usually cut a piece of green scotchbright pad to fit end of a paint stir stick or chopstick, tape it on with elec tape. This works well on older Emerald, Marquis, and newer 5.5 and 7 kw sets. Just remove brush block for access to rings. You dont specify what model of 4K Onan you have, but likely a 4KY Microquiet. the brushes are behind fan/flywheel and will require some disassembly to access brushes on this model2.3KViews0likes0CommentsRe: Onan propane rough, quits
the 3.6KY LP Onan genny's can be a real handful to diagnose with the symptoms you describe. After checking all the basics (compresion, ignition, fuel from tank to genny), you may want to replace the LP hoses on your set, due to their age. I have done this to several sets that were brought to my shop with this problem, and it seemed to fix issues. the fuel pressures to and from LP regulators are very critical, and any deterioration of hoses can cause problems. if you have any "backfiring or popping back" through carb., make sure to check rocker arms and valve lash.801Views0likes0CommentsRe: Onan 3.6KY Propane Generator Starting Issue
happy that you were able to repair without spending lots of $ on parts. AS I am in generator repair business, I have found this to be problem on over 50% of LP generators that come in for repairs. I usually cover open end of hose with some screen and a tie-wrap .1.5KViews1like0CommentsRe: Onan 3.6KY Propane Generator Starting Issue
When you say the generator will not "start"...do you mean it will not turn over (crank) with starter, or it cranks but will not run? The problem with LP fueled systems is usually fuel related, and many times is simply a plugged up LP regulator atmosphere vent hose. Insects, namely wasps or dirt-dobbers love the smell of LP and crawl up hose, build nests, and stop up the hose. then the regulator diaphragm cannot move freely to allow fuel to engine. Do not blow high pressure air into regulator, it will rupture diaphragm. remove hose from regulator, then blow it out. Of course, do basics first. Ensure spark is getting to spark plug, and regulator at fuel tank is supplying fuel to generator.1.4KViews1like0CommentsRe: Gen shuts off unless “Start” held down
your Onan 4KY spec H does not have a low oil level sensor, nor does the control board have fault code diagnostics. OP is probably correct, that generator is not producing AC power, which control board has to "see" to turn on run relay on board. Most common causes are bad field brushes or bad brush contact with rotor slip rings, bad voltage regulator, or bad control board. Worse case scenario is gen. rotor or stator shorted or open winding. Getting to field brushes is somewhat involved, as the fan/flywheel needs to be removed for access. Voltage regulator and control board are expensive items, so throwing replacement parts at it in an attempt to fix it can cost a bunch of $$$ and very possible would not work if brushes/rotor/stator are bad. Replacement control board and voltage regulator are available aftermarket from FLIGHT SYSTEMS in PA. Best bet is to find a qualified ONAN service to accurately diagnose problem. Good luck3.2KViews0likes0CommentsRe: Onan generator shutting down after releasing start button
Mr Wizard's info is pretty much correct. If you are getting 20vac at 30amp gen receptacle, then most likely a "field" problem. Even at only 200 hrs, the field brushes might be sticking in the holder, or the slip rings are oxidized or dirty. possibly a control board going bad, as the field (voltage regulation) is part of the control board. Unfortunately, brushes/slip rings are not easily accessible, as they are located behind fan/flywheel assembly. there are troubleshooting procedures to determine problem, but some specialized test equipment needed. BTW, no low oil level switch is used on this spec 4KY.1.2KViews0likes0CommentsRe: Onan 3.6 won't crank
need to know "spec" letter, and serial no. of gen to know which control system you have. In any case, oil level has NO EFFECT on starter and cranking operation. Older spec units did have low oil level cut out switch, but did not prevent starter operation. And...these units dont hold much oil (imho) and should be run at full crankcase level for maximum engine protection. Lots of useful info on internet,,,lots of B.S. too1.3KViews0likes0CommentsRe: Onan 3.6 won't crank
bear in mind that Onan start/stop control switches are switching grounds, not batt voltage. Sounds like your start solenoid and starter are ok since it cranks when you jump 12v to solenoid start solenoid. Since neither switch will activate starter, I would suspect bad control board or ground circuit to control board. Also, disconnect remote panel wire harness, and try it at generator control. If it cranks now, you have a shorted harness on stop circuit, as the stop circuit overrides start circuit.1.3KViews0likes0Comments
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