Onan generator fuel pump question

[wizechatmgr]

For giggles. Let her run, let her come up to temp.

Attach one AC, see if it almost immediately recovers speed or not. Try to watch the throttle/governor at the time this happens -- if you have a mechanical one you can watch. If you see nearly no response and it is mechanical you're clogged with undesirables.

I'm not sure about your particular model *pardon my ignorance* but you either have a mechanical link for the governor/throttle or you have an electronic one. The mechanical usually has a vane that has air pushes against to regulate the speed - this can get gummed up with crap such as leaves, spider webs, dandelion spawn, etc. The electronic I haven't run into much (worked on older engines) so if this is the case one of the awesome peeps on here will be able to give advice on that.

What is the previous service intervals you've been using?

[Virago-Rider]

Change oil and fuel filter every 6 months.

New spark plugs yearly. .... Changed them with this mess, just to be sure.

Exercise it for an hour under load twice a month.

100% real gas, no ethanol.
Lucas fuel treatment every other tankful.


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[wizechatmgr]

There is an interesting article on how to troubleshoot and adjust this style generator - if you're handy with tools and buy the right equipment you can do it, or, pay someone else as this looks like it could potentially be a pain in the rear. There is significant risk of bodily injury if you don't feel you have the skillset required...

Onan Generator Troubleshooting Article

[Waiter21]

You are at the limit of your genny if you're running two AC units on a 4k genny..

You may have picked up some debris in the carb. As others mentioned, You might want to pull the bowl off, clean it, then spray carb cleaner through the passages and tubes.

ALTITUDE - Make sure your altitude selector didn't get bumped and is set to your approximate altitude.

When I start mine, I hold the STOP button in for 20-30 seconds before attempting a start. Holding the STOP button in runs the fuel pump and fills the carb bowl..

[JRMEDPHYS]

Originally Posted by Virago-Rider

Update...

Changed nothing from two days ago...



Ok.... Got in from work, went out to the camper. Turned on batteries, fired up the generator... Stumbled and sputtered for a minute or so. Then smoothed out... Stable running no load.

Turned on 1 air conditioner... Everything fine.... Ran 40 minutes... Stable.. Voltage 126-128.

Turned on second are conditioner.... Gen lugged way down... AC volts dropped to around 100. Both ACs stopped due to low volts. In all the years we have owned this camper we could run both ACs on generator with no problems.

After both ACs shut down, voltage recovered to 127-128

After the short cycle circuit on the ACs timed out, I could run either one just fine. But, not both.

Very puzzling.

The service docs provided by SpyderRV a few posts up,....talked about adjustment of the governor. But, requires a frequency meter.... I don't have one.


Still in search of an answer

Thanks


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

Yup...check the governor. Might need to be adjusted or repaired. Linkage or spring might be broken. When you add load, the governor needs to speed up the motor to keep the genny section operating at the right frequency to match the demand. 2 A/Cs on that genny is pretty close to max load.

Cleaning the carb is not a bad idea either while you are there but I really do think you have to service the governor from what you have described.

[Virago-Rider]

Can't fully access the entire governor linkage due to the brilliant way the generator is mounted... However did manage to get some wd-40 to the end joints that I could see. Ran it for 45 mi Utes with 1ac. Voltage stable... May try two ACs again..... But don't want to push my luck.


I finally had a reply from the guy at flight systems..... The same guy that concluded the problem was my control board and sold me one of theirs...

This time his reply was that he didn't have much technical knowledge and I should probably contact another person.. 3 emails to this other person and no reply yet.


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[wizechatmgr]

At least you now have a spare control board for the day the need arises...

Hate it when people have no problem selling you something but have no knowledge of it. They assure you it will do everything including producing diamonds and propel you to the moon...

[Virago-Rider]

Fired up today, RPMs not stable. Governor linking constantly moving....

Removed carb bowl, clean.... No varnish, no debris.

Reinstalled bowl. Removed gas line, filled bowl with sea foam. Reattached gas line. Let it set a few hours. Cranked it until it started. Being full of sea foam, it smoked for a while. Once the smoke stopped, turned on 1 AC. RPMs again not stable. Governor linkage constantly moving.


So far...
New spark plugs.
New oil
New oil filter.
New flight systems control board.
New fuel pump
New fuel filter.
Cleaned carb
Removed and cleaned gen to chassis ground connection.
One by one removed and cleaned each connector inside the box with the control board.
Applied WD-40 to the pivot points on the governor, throttle plate, choke plate and choke linkage.
Gas in the tank is 100% gas, no ethanol. And less than 1 month old.

Still lost


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[twinboat]

Your engine sounds like it's running lean. That happens when the main jet and passageway get gummed up.

Chemicals will not replace good old fashion fixing. Take the bowl off and clean the main jet ( brass thing sitting in the bottom of the bowl ) and passage up to the throttle bore.

I strip thin copper stranded wire and use it like a brush, up into the jet.The jet and nozzle get a varnish like coating, that blocks the gas from being sucked up to the carb barrel.

You may want to unscrew the jet to clean the main passage up.

Pull the float pin and remove the float, with the needle clipped to it. Blow thru the gas line to dislodge any stuff in that passage.

Take care to put it back together. With carb in hand, upside down, float should sit level and you shouldn't be able to blow, with mouth, thru gas line inlet. Carb right side up, float hanging, you should.

Your governor is a internal mechanical flyweight design. If bad it wouldn't hunt. Don't mess with it unless volts or cycles are steady low or high.

If you were overloading the electrical end, you would trip a breaker, not stall the engine. That's not your problem.

Good luck

[BGDDYRV]

when the engine slows down is the governor full on or can you manually increase the speed? The fuel pump from the factory is only 4 psi so make sure that your replacement is the correct pressure. if you have an in line spark tester check that both cylinders are firing and if so check compression which should be even across both and about 125 PSI. That generator is very good and it will run on one cylinder and you wouldn't know it.
If the unit sat for for awhile with fuel in it the carb will become a problem and should be replaced....we stopped rebuilding them because by the time you soak and clean it, the parts and labor was close to a factory fresh one and those jets are tiny.
This is what we do so if you want to email me at bill@donhillmaninc.com your findings I will try to help you.

If the unit doesn't produce electricity it will not stay running when you let up on the start button. Electricity is not your problem now but engine and unstable governor can be a bad carb. grab it and run it manually and if you can't make it hold then see above.

[Virago-Rider]

Thanks for all the replays, keep them coming.

The gas is not old, and I have never let the gen just set. I exercise it 1 hour minimum with load every two weeks.

I haven't yet been successful at removing the carb with my big hands as there is only about 2" of clearance above the generator

The replacement fuel pump is a genuine overpriced Onan replacement..


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[Virago-Rider]

I have gotten nowhere on Google..

The plugs show the gen is running very lean.

If I carefully reach my fingers around and pull on a little choke, it runs much better.

Altitude adjustment one the bottom is pointing at zero.

How do I adjust the carburetor a tad bit richer?

Photos would be awesome


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[okcnewbie]

Originally Posted by Virago-Rider

I have emailed flight systems... But, no reply as of yet..

I wouldn't give up on flight systems. They have helped me without even buying a part. They may be busy at the moment but they are top notch in my book.

[Virago-Rider]

I will send email #4 to them and see


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum