Kohler engines ?

that's kind of odd for newer equipment, but sounds like a carb problem or maybe air filter
Pressure washer Running poor ? Video | Firewood Hoarders Club

 

Surging under no load at throttle is so typical of ethanol fuel.
You can either try to adjust it out by richening the fuel (if it has adjustments, if not-just a touch of choke will work)
Or run a can of True Fuel and watch it clean up.


How do you like that splitter otherwise ?

 

The surging can be from a whacked out carb...due to gelled or crystallized fuel that screwed the carb up. Often tea you can't fix it with a rebuild. Just have to buy a carb.

Maybe a pitted seat from water in fuel corroding it and needle can't seal it off.

 

There shouldn't be any old fuel in it. Only got it in January. Used it a few times and then put away until July. Had stabil in it. I only run premium fuel as well. No e free gas stations around here. I can get 5 gallons of canned e free for 60 bucks locally though. I am also a few minutes from a local small airport. They might hook me up with some aviation fuel.

 

Easiest way to tell is to warm up the motor and allow it to surge at no load, then start slowly closing off the choke (ever so slowly) and you will see how she cleans up.

Most newer motors wont allow you to adjust the mixture

You might find that regular instead of premium allows it to run smoother

I have a generator at work that would surge at load as well as no load (no carb adjustments)
My boss thought I was cracked when I told him that it is the ethanol in the fuel, and wanted to return it again (this being the 2nd generator, exact same thing happened with the first one).
I brought in some of my VP SEF, and right in front of him drained the pump gas and poured in the VP
It took about 10 seconds to run clean, and it runs clean all the time, under a load and at no load.
We now keep 5 gallon drums of VP in the fuel storage for the generator and jetter

 

Premium is nothing but higher octane E gas??? Better off with 87 cause its fresher. And that is a long time for fuel to sit now. I have had gas go bad...stink like bad gas in as little as 8-10 weeks

 

I have also found an out of spec governor spring or linkage will causes this. sometimes a bump will bend the sheet metal the spring is attached to and throw it all out of whack

 

I have a 69' Lickity Splitter with the original K series Kohler 8hp. Compression getting a bit low now but,it starts so well I hate to tear it down.

 

I wouldnt touch it then

 

Not going to till it just won't go no more.
I bent the wore out top plate and had to rebuild it. Gave a quick Earl Sheive while apart.
Motor and pump still original.

 

oh my, I haven't heard that name in years,

 

Running premium had in motors designed for lower octane makes then run worse, wastes $, and make less power.

I've got a feeling you carb is gunked up...

 

I run Kohler toilets in my house...

 

you should try the american standard champion 4
virtually uncloggable
like Al Bundy's Ferguson

sorry