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Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14994
Experience:  Certified on Onan and Generac generators
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Champion generators model c46535 3500w, did not run when got

Customer Question

Champion generators model c46535 3500w, did not run when got it, found fuel system clogged, Cleaned fuel valve, carburetor, jet, and got running but RPM would osculate, adjusted low idle stop screw till ran smooth, (all the way in), Seems to run fine but when I plug something in to it runs at half speed. Doesn't seem to be putting out enough voltage. Any ideas (took carburetor back off to check float and float seat, found that jet was not all the way seated) Reassembled and seems to work with some things but not others is their a way to check if it is putting out the right HZ. The voltmeter seems to be all over the place from 110v to 130v. I can adjust the RPM and it sets the voltage but what do I set it to (I assume 120 Volts) and what HZ is it putting out. Seem to be running a bit fast now. All ready adjusted to low idle speed screw back to where it was.
Submitted: 6 years ago.
Category: Small Engine
Expert:  Hank F. replied 6 years ago.


You can not set a gensets speed by voltage - you must set it by frequency.


A frequency meter is required to do this.

The frequency should be set to 63 Hz with no load applied to the set.


If the engine is still surging, this is a sign of a bad carburetor. You will either need to reclean it properly, or replace it.


Customer: replied 6 years ago.
I know that I asked how do I set the HZ. I tried. the gen is not surging any more (see Question Fixed surging problem ) I want to know why the HZ will not stabilize and why it wont regulate and how to set it. If i hold the butter fly valve closed to the low stop it It runs good at 63 HZ and runs most things on my camper but as soon as I load it up is bogs down. If I rev it up past 60HZ it will run the A/C but nothing else (to many HZ) It wont Idle down low enough to run at 60 HZ. Its like their should be a voltage regulator or something, Or a governor thats kicks in to hi or low that is not working. It runs smooth (RPM wise ) but the voltage and HZ is not very constant. It stays around 120 volts all the time. On my hand held volt meeter it is from 120 to 125 volts and from any where from 60 HZ (if I hold the butterfly valve on the carb to the low stop) to 150 HZ or more at high (If i just let it run.) What do you think. Thanks Hank
Expert:  Hank F. replied 6 years ago.

The frequency (Hz) is directly controlled by engine speed.

The faster the engine is running, the higher the frequency.

Some voltage variation is normal.


The engine speed is controlled by 2 things - a properly functioning and properly set carburetor, and the governor.


Even though you may not hear the engine surging, if the frequency will not stabilize - the engine is surging.

To compensate for this, very fine adjustments must be made to the governor.

To properly do this requires the use of a load bank, which is a calibrated load.

You first set the carburetor mixtures (if they are adjustable) to obtain the highest frequency setting with no load.

You then adjust the governor speed and sensitivity to obtain the smoothest running at about 63Hz.

Then you apply a full load to the set, and readjust the carburetor main mixture until the highest frequency is obtained, and readjust the governor if necessary.

Droop should not exceed about 12V.


Edited by Hank F. on 9/7/2010 at 3:37 PM EST
Customer: replied 6 years ago.
Thanks that helps and makes sense but i don't know where the governor is and how to adjust it. I think I can come up with a pretty fair calibrated load. what should it be. Sounds like maybe their is still something wrong with the carburetor. It seem pretty simple But im no expert. Its is all really clean and I checked all the passages for obstructions. their is not a real mixture setting just stops for the butterfly valve for low and high. The float looks fine and the float seat is normal. I would like to look in to the governor. Any way to check it out to see if it is working properly. P.S. I will change the balance to more as soon as I find out how to do so thanks for your time
Expert:  Hank F. replied 6 years ago.

If you have not been adjusting the governor, there is less than a 1% chance the governor is at fault.

The problem is still most likely in the carburetor.

A carburetor can be the cleanest thing you've ever seen, and still be no good.

The problem is not what you can see, but what you can not see. There are some very tiny passages inside the carburetor you can not get to. It is these passages that create problems.

The only real way to clean a carb is to remove it, disassemble it, and soak it overnight in a commercial solvent. Then use a spray type cleaner to get all of the solvent out of the passages.

Even with a soaking, sometimes a carb will simply not come clean, and it must be replaced.

This is the single most common issue with small engines - particularly ones that do not get used regularly.


To see if the governor is working, simply start the set. Manually try to speed the engine up with the throttle lever and let it go.

If the engine speed comes back down, the governor is working.

But it may still need to have the sensitivity adjusted.


For a calibrated load - it must be precise. Pretty fair will not cut it.

You must apply a full load to the set.

If your set is 3500W, you must put a 3500W load to it.

It must also be a steady load - motors will not work, as the amperage draw is constantly changing.



Customer: replied 6 years ago.

I didn't soak it over night but I did blast carb cleaner through all the passages and then blow them out with compressed air (90 PSI) All were clear. This could be the problem still because when I took it apart it was full of really nasty stuff. The bowl looked like it was full of red mud (bad fuel) and the fuel valve was gummed shut with fuel varnish. I can rev it up and it will come back down but only because their is a spring pulling the arm back down. Their is a set screw in that arm with a spring under the head that was all the way turned down tight when i got it. (I think this is called the control assembly) The other spring attached to the arm is what is pulling the butterfly valve back open. Do you think the governor is working and I need a new carb. Is the governor in side the engine.


I am a A&P Mechanic and have access to a load tester for aircraft generators I think that would work Just need to rig up a plug to the test cell. I think i make that work. Just run it to the max load on the chart on top of the generator I guess.

Expert:  Hank F. replied 6 years ago.

This really sounds like a carb issue. You really need to soak it.


The governor works backwards of what you think it does.

At rest, the spring pulls the throttle to the wide open position - not to idle.

When the engine is running, the governor tries to slow the engine down. This is why you need to manually speed it up to test the governor.

The governor itself is inside the engine.

If the governor were broken, what would be happening is that the engine would be racing - there would be nothing to pull it down.

Any load bank will do. You just need to run a full load on the genset.

Customer: replied 6 years ago.
I will soak the carb then try it again. But im still not sure the gov is working the why the gen is working now it runs full bore it seems an i have to move the screw on the control assembly way out and hold the butterfly closed to get the thing to idle down. I Had to go start it again it has been doing so many different things I kind of gave you some bunk info sorry it runs full bore now it seems not to want to idle down.
Expert:  Hank F. replied 6 years ago.

If you believe the governor is not working, try this.

Manually move the governor arm from stop to stop and note how much spring pressure there is on it.

Disconnect the governor spring.

Move the governor arm to mid position and hold it.

Start the engine.

You should feel a pressure on the governor arm about equal to what the spring pressure was. If so, the governor is working.


Customer: replied 6 years ago.

Well I don't feel any pressure on the arm but the spring tension is not much to begin with. I seems that with all the springs off i still have to hold it in low idle for it to idle down. Is their an amount of movement the gov arm should l move it doesn't seem to be moving much, and it seems to have lots of play.

Expert:  Hank F. replied 6 years ago.

There is not much movement on the governor - maybe an inch total at the long end of the arm.

Did you by any chance ever loosen the locknut where the governor arm is attached to the governor shaft?


Customer: replied 6 years ago.
no but was about to. lol. I have it marked with an index mark.
Customer: replied 6 years ago.
I think I should try one thing at a time I will get the carb cleand up again and flush out the gas tank. make sure it is clean. then give it a go. Is their a way I can get in touch with you again after I accept answer. I think maby more than one problrm here. This generator was in my dads garage for years unused. Till I decided to use it. The gov sounds suspect to me but I think the carb sounds fishey to me to.
Expert:  Hank F. replied 6 years ago.

Yes, we need to start from scratch - and everything hinges on the carb doing it's job.

Let's get it properly cleaned or replaced.

Then we can move on.

Since the carb has been tampered with, we are going to need to reset everything.


This is your question, and you will always be able to come back to it - even after you accept.

If you wish to wait to accept until we get it running, that is fine with me.

To accept now or later is totally your choice.



Customer: replied 6 years ago.
Agreed. I know my dad has tampered with it a bit to and I have no idea what he has done to it. I think it was him who bottomed out the controller screw. don't know. Lets wait till its running I may be a few days so thanks for the help and your patients. I just don't know much about small engines. If I don't get it cleaned or replaced in the next few days I will be out of town Elk hunting for the next week so you won't here from me till then. (I'm fixing it for my uncle so he will have to wait.) Hope I can find some time In the next few days. Thanks for your time. By the way my name is Gary,
Expert:  Hank F. replied 6 years ago.

No problem at all, my friend.

Just let me know when you are ready.