Small Engine Problems? Ask an Engine Mechanic for Answers ASAP
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.
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.
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.
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.
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.
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.
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.
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?
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.
No problem at all, my friend.
Just let me know when you are ready.