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Ruediger · 12-14-2021, 11:38 AM

Since buying m rv in 2020 it run once. Took me some months to find the 'at least 25 percent filled gas tank needed' rule. Now im working with a jerry can and fresh fuel. These days i need it. But just cranking. What i did: oil/ filter somehow new. Carburator cleaned. While cranking, exhaust fuming. Spark plugs almost new and fine against ground. But the cranking only as long as i'm on the starter button. I checked also the oil pressure sensor (against ground). Fuel pump good. Fuel filter not blocked. Spark plugs black and covered with soot. Oil is full. No visible defects on cables or connectors. I downloaded all docs. Also for troubleshooting. But still a lot of options. My gut feeling: something is shutting down the gen. But what? Help very much appreciated.

Roy-c · 12-14-2021, 01:32 PM

I have a few questions.How long has it been since it was run ? It draws fuel from the main fuel tank but the fuel is stale & the tank is at less than 1/4 full ? How did you clean the carb and what do you mean by somehow the oil & filter are new? I am a little confused. If it has compression, fuel & ign. it should run. You said it has spark and the spark plugs are sooty ( but not wet ) Sounds like lack of fuel to the cyls.

vito.a · 12-14-2021, 01:49 PM

Onan generator carburetors do not store well. Most of our gas now has ethanol in it which is corrosive and ruins the carburetor. If it has been sitting for several months you will need to remove the carb and clean it. Or, in some cases replace with a new one.

donr103 · 12-14-2021, 01:55 PM

Use all safety precautions.. and try starting fluid.. take air filter off at carb.. and spray inside carb while cranking.. keep good fire extinguisher handy and or wet towels and or garden hose.. report back what happens..
Good luck and let us know what you did and maybe better members then me will help you

Ruediger · 12-15-2021, 02:24 AM

Quote:

Originally Posted by Roy-c

I have a few questions.How long has it been since it was run ? It draws fuel from the main fuel tank but the fuel is stale & the tank is at less than 1/4 full ? How did you clean the carb and what do you mean by somehow the oil & filter are new? I am a little confused. If it has compression, fuel & ign. it should run. You said it has spark and the spark plugs are sooty ( but not wet ) Sounds like lack of fuel to the cyls.

No need to be confused.

As said, I´m working with a jerry can. Simply because I run my RV with propane. Full tanks not require. The jerry can is filled with fresh fuel. I disassembled the carburetor down to removing the bowl, extracting the single jet. And needle. No major residues.

Oil/ filter somewhat new: Changed them last year. But didn´t exercise inbetween.

From analysing the web with onan problems, there are many other causes affecting the Onan not to run. I like one sentence the most: If it looks like a fuel problem, it mostly an electrical problem. My gut feeling is also going is this direction. The sooted spark plugs let me also look into a defect choke. Sooty spark plugs IMHO the contrary of lack of fuel.

Ruediger · 12-15-2021, 02:25 AM

Quote:

Originally Posted by donr103

Use all safety precautions.. and try starting fluid.. take air filter off at carb.. and spray inside carb while cranking.. keep good fire extinguisher handy and or wet towels and or garden hose.. report back what happens..
Good luck and let us know what you did and maybe better members then me will help you

Thanks, Don. I´ll test this today. With all recommended precaution tips.

Ruediger · 12-15-2021, 02:28 AM

Quote:

Originally Posted by vito.a

Onan generator carburetors do not store well. Most of our gas now has ethanol in it which is corrosive and ruins the carburetor. If it has been sitting for several months you will need to remove the carb and clean it. Or, in some cases replace with a new one.

I learned this the hard way. I have solar panels on top. And simply missed the regular exercises one a month. Lessons learned.
Carb fully removed. As mentioned: Pump working, filter not clocked. Carb bowl full of fuel. The sooty spark plugs from side a strong sign for: Carb working.

I´ve also seen the replacement options. I´m in Spain for now. Boondocking. We often have to trust our gut feeling. And mine is: Not the carb. But I will report how its going.

Ruediger · 12-15-2021, 06:57 AM

Quote:

Originally Posted by donr103

Use all safety precautions.. and try starting fluid.. take air filter off at carb.. and spray inside carb while cranking.. keep good fire extinguisher handy and or wet towels and or garden hose.. report back what happens..
Good luck and let us know what you did and maybe better members then me will help you

Did it. One side of the muffler flow away like a frisbee. Internal explosion of the starter spray residues. Sounded like a gun shot. People running around possibly thinking to call the local SWAT team.

But the same: Running somehow nicely. But shutting off after stopping pressing the starter button.

I again tested the oil pressure valve against ground. Also switched off/ on the two main switches (black/ white) on the right side. No effect. I also reduced the oil level. Read somehwere, that "full" might be to much.

Choke also working as far as I can see it.

Saw comments that the brushes might be a cause.

I´m looking for someone telling me what kind of shut-off procedures exist.

Ruediger · 12-15-2021, 01:41 PM

And the first follow-up. Chatting with brian from flightsystems. Good youtube videos. Excellent first advice. Checking electrical parts/ regulator today upon request. They know what to ask for. One def shut down rule for onan emeralds is, if there is no ac output. To be measured at the circuit brakers. Reason could be: slip rings corroded. Will test it tomorrow. Also the brushes. Step by step. I will report, when i find the cause. Flight systems now on my short list, if onan parts to be ordered. Or problems with the genset occur.

donr103 · 12-15-2021, 07:23 PM

So you go it running on starter fluids.. next would be turn breakers off that are mounted on the right side on gen.. next clean slip rings.. use slick stick from flight system.. hopefully that will signal the voltage regulator and tell gen it is making voltage.. and keep running.. also make sure your main fuel tank is topped up.. watch you tube vids.. on FLIGHT SYSTEMS GEN REPAIR.. watch all of them.. how did you clean carb. ..?
Good luck and keep us posted..

Ruediger · 12-16-2021, 02:49 AM

Quote:

Originally Posted by donr103

So you go it running on starter fluids.. next would be turn breakers off that are mounted on the right side on gen.. next clean slip rings.. use slick stick from flight system.. hopefully that will signal the voltage regulator and tell gen it is making voltage.. and keep running.. also make sure your main fuel tank is topped up.. watch you tube vids.. on FLIGHT SYSTEMS GEN REPAIR.. watch all of them.. how did you clean carb. ..?
Good luck and keep us posted..

Not for now. I today test the breakers and clean the slip rings. Later today a call with flight systems. Moving towards a solution. My feeling.

Ruediger · 12-16-2021, 08:36 AM

Tested. Found stuck brushes. And thought, whammm. Got it. But the same. No ac between the breakers. Thats where flight systems raised the white flag for now. I wont stop until i find it. But today is winterizing day. Back on the road in march.
Thanks for all the input.

donr103 · 12-16-2021, 11:52 AM

Ok.. you are working on several problems at one time.. you can see that you are dealing with multiple problems.. so you just got to keep working through them.. one at a time..
So how about an update? So we can give you better opinions.. so did you get slip rings clean? And fix brushes ? Is eng running at all? Have you looked in appliance section and download the manual... and trouble shooting guide ? Does eng start and run while holding down switch on gen? Have you pulled circuit board yet? If you do pull circuit board... use cellphone with camera and flash and record where all wires go..
Good luck and let us know

Ruediger · 12-18-2021, 02:29 AM

Thanks for your comments. I have a slightly different view. Many things working/ or are already examined. The problem in the shut-down procedure. There are a handful. Smokestak an excellent source finding in depth expertise. I do my homework now. And will be back on the road beginning of march. And will report here until the problem surrendered.

For now everybody a Merry christmas. Good days back home with friends and family. Irv2 simple a great forum and has been and will be a great help for me. And i'll keep the flag for american motorhomes in in central europe raised. [emoji6]