Honda GX390 Surging Problem

Casey my one machine was doing that. I had to much oil in it. I took some oil out and changed the plug and all is good . Now my other machine is surging when I let off the gun. Not sure what up with that machine. I now everything under the air filter is complete rust. I'm thinking govener sticking.
 
Its a long shot but it may be possible the flyweights on the governor shaft may be sticking. you could try running some seafoam in the oil for a while to try and clean it up then change the oil and see if it helps. otherwise you would need to pull the back cover to inspect it.
 
My machine has a Honda GX390 13-HP motor with a General 4040 direct drive pump.

The pump and unloader probably have less than 100 hours on them. I am guessing the motor has around 500 +/-. The motor has always ran great until the end of last year.

It seems to hunt or surge when I release the trigger after spraying. You can hear it and watch the governor arm move back and forth. The problem is not too bad when the machine is cold but gets worse the longer it runs. I have actually had it die in me in the past which is a huge PITA to stop what you doing and have to restart it. It seems to get better after the motor cools down a little.

Here is a video of the machine running and surging. Is is pretty apparent about :25 in.

Here is what I have done and tried so for.
-Disconnected the oil level sensor
-Cleaned out the gas tank, line, and fuel filter in the small bowl. (Everything was clean.)
-Tried fresh 93 octane gas.
-Tried running with no gas cap.
-Air filter and spark plug look like new.
-Removed the carb and cleaned the jets. Blew out all the passages in the Carb. Carb looked spotless. Carb to intake gasket did not have any tears or holes.
-Checked the governor arm where is goes into the block. Everything seems tight.

Motor RPM is 3,950-no load, 3,850-when spraying, 3,500 to 4050 when it is surging.

About the only thing I can think of is to order a new carb. Does anyone have any other suggestions? Thanks!
I know it’s been awhile, but I have the same issue. Did you happen to solve the surging problem Casey?
 
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