Onan Microlite 4000 Generator Issue

[WingsFan1313]

Good evening, folks!

I will be purchasing my first-ever motor home on Monday; It's a 2002 Fleetwood Tioga with an Onan Microlite 4000 generator. During preliminary discussions with the seller, he indicated an issue with the generator not starting. The price is too good to pass up, even if I need to replace the generator, but I thought this might be a good place to get some advice on whether it can be fixed or if it needs to be replaced. I will try to provide as much information as I can, but I'm completely new to this so please forgive me if it's not enough.

During the walkthrough today, here's what happened:

- The motorhome was connected to his house for power and everything inside was working fine (lights, TVs, etc).

- We attempted to start the generator by flipping the switch to generator power and holding the start switch. There was a clicking noise as if trying to start a car with a dead battery.

- We moved on from the generator and started the engine of the motorhome... and while the engine was running, he attempted to start the generator again. This time, it attempted to start, but would only run for about a second before quitting.

- My friend (who is much better at these things) opened the generator door to look inside and told me that when he touched the carburetor on the generator, he got an electric tingle -- that there was a short to ground.

The seller said that he hasn't run the generator for about 6 months, so I can understand a carburetor issue (gunked up, needs cleaning or replacing), but the electrical issue has got me confused.

I will have the motor home on Monday and can provide more specifics then... I just wonder what the first plan of attack should be.

Thanks in advance. I appreciate any help you can provide.

[Dusty_R]

The grit on emery cloth is a conductor, where the grit on sand paper in not a conductor. Learned to never use emery cloth to clean electric contacts.

[Kpackpackkelley]

MEXICOWANDERER wrote:
RECOMMENDED REGARDLESS

Coarse emery cloth. Disconnect house battery negative cable

Then one by one disconnect and shine up all cable connections to the generator.

Do the ground cables as well.

This will keep you busy and bright connections are essential. Wire brush threads

Listen to what he is telling you.

[MEXICOWANDERER]

RECOMMENDED REGARDLESS

Coarse emery cloth. Disconnect house battery negative cable

Then one by one disconnect and shine up all cable connections to the generator.

Do the ground cables as well.

This will keep you busy and bright connections are essential. Wire brush threads

[Kpackpackkelley]

If you start adjusting anything make a mark and count turns of screws so you can get back to where you were encase you need too.

[Kpackpackkelley]

http://www.skilledcrafting.com/onanfiles/
Model and spec letter of gen will get you to the service manual.

[Kpackpackkelley]

http://www.skilledcrafting.com/onanfiles/

[STBRetired]

The manuals for the Onan generators are available online. There is a section on how to adjust the governor.

[Kpackpackkelley]

When you get your multi meter you can test better. Could be a number things.

[WingsFan1313]

I went out a little bit earlier today and just tried to use the microwave with nothing else and it did the same thing. I'm seeing online that I may have to adjust one of the arms feeding the carburetor... But I'm still doing my research on that.

[Kpackpackkelley]

Run your ac on shore power and if your dvm is a clamp On you can see how many amps it’s pulling. Your ac could be pulling to many amps for the generator.
Does your generator do the same thing when you turn on the microwave and the hot water heater at the same time ? They should be a little over 20 amps with nothing else running.

[WingsFan1313]

Thank you so much to everyone for your help. I got my motorhome Thursday of last week, and I have learned so much because of your help. I'm not mechanically inclined at all, but I've gotten so far with everything this week and there's no way I would have been able to do it without you folks.

UPDATES: I changed out the carburetor (all by my freakin' self -- that's huge for me) and IT STARTED AND STAYED STARTED! I got giggles and goosebumps because I seriously stink at anything automotive/electrical/small engine so this was a major achievement for me.

NEW ISSUES: So the generator runs great -- fires right up, stays fired up... until I try to turn on the air conditioner. As soon as I flip the switch to COOL, the generator starts spasming -- the only way I can describe it is like a sine wave of high to low -- WHIRRRRRrrrrrrrRRRRRRRrrrrrrrrRRRRRrrrrrr. I know that's the absolute newbie way to describe it, but that's what it's doing. I don't want to do any damage to the generator, so I turned it off, turned the AC off, and then a few minutes later, I fired up the generator again. Works like a charm... until I try the AC again... same deal.

If anyone has an idea, I'm all ears. I know so much more about this thing now and I can't wait for my DMV to finally open so that I can get plates and get moving. 🙂

[travisc]

Check the obvious air filter and spark plug. You should do that anyway and change the oil while your at it, ours did that and we cross referenced the plug online and got one at auto zone and our was running again.

[WingsFan1313]

Hey everyone! I just wanted to follow up on all of your suggestions and get a couple of questions answered now that I have the RV in my driveway. 🙂

The Hot Skin issue: We figured that out -- the shore power plug has a loose ground connection... so I will be replacing that and then I will check to see if it's still doing it. So -- hopefully one problem down.

The Dead Battery Issue: I don't believe that the house battery is dead -- The indicator lights show 3/4 to full power when I use the battery test button and the engine will start if I override the engine battery and try to start it with the house battery. Also, the generator will try to turn over when being started from the house battery -- it just won't come on and stay on. I might replace it anyway, but that may be two problems down.

The Generator Start Issue -- So having taken your suggestions, I put fresh gas into the tank (up to 3/4 full) and we checked the generator oil -- it was at an appropriate level and looked brand new. We've tried to prime it by holding the STOP side of the button for 3-5 seconds each time before we try to start it. It tries to turn over and will sputter a couple of times before quitting. All signs (to my friend and me) are that there is a fuel issue -- carburetor needs cleaning or something like that -- but I'm new to all of this and don't necessarily know how to do that. I would like to follow up on the following, though...

- I don't see any lights on this model to see if there is an error code or if the generator is primed. Where, specifically, should I be looking?

- I was under the impression that the carberators on these are sealed and cannot be cleaned in a normal way. Am I wrong? Is there a video somewhere that can show me how to do it? EDIT -- I found a couple... but if you have a go-to one that's awesome, I'd love a link.

- When I'm priming the generator, should I hear something happen? (Fuel pump kick on, etc...)

Sorry for the long post with so many questions -- I really do appreciate all of your help.

[1320Fastback]

Same Gen in our 2005 Forest River. The start buttons need to be held down to Stop for 3-5 seconds to prime the fuel system. There is a indicator light that goes out when it's ready to start.

Also oil level is critical on these generators. Check the oil level, it is low it will not run.