Sounds like a dirty carb. The Honda fuel system needs to be squeaky clean for the engine to run properly. Is your gas fresh? I bet this is the first time your mower has been run this year.

Yeah, new gas with Stabil. I drained the carb bowl but did not take apart the carb. Is this difficult for the average Joe? Do you need to disassemble it or can you take off the bowl and get to it? Thanks in advance.

2 years old, should be the OHC engine. The carbs are EZ but do need removing, your idle ciruit is probably the problem.

Trouble is the OHC carbs are a snake to R&R for the first timer.

Me and a friend both had this problem with our mower, they would only run on high speed and would pulse or surge at idle. Tried cleaning the carb but that didn't work, tried replacing all the gaskets, no improvement. Bought a new carb from Plano Power Equipment for a whopping $16, along with the governor spring and rod, spent about $31 total. Installed the new carb and it purrs like a kitten, idles, runs on any speed, just like new. I did also move the spring on the lower right that attaches to the governor lever from one hole to another. Seems the carb and associated linkage is very touchy, that's why I replaced the other parts but the carb may have had a clogged jet and I just didn't feel like messing with it so replacing it did the trick for me.

well i put new gas new factory carb new blades cleaned muffler new plug adjust valves rechecked blade aliment, new air filter. still surges so what now it is a honda harmony 2 .5 years old.

albert
I'm right there with you. I replaced my carb, air filter and spark plug and got it to fire up. However, it's now surging.

I'm going to look at lawn_dude's advice and mess with the springs (wish i had bought new ones and saved some $ on shipping).

I'm also going to make sure my gas cap is venting properly.

I'm just glad fall/winter is here and that my grass has started to go dormant.

Is the blade turning on this model, Albert, or do you engage the blade after the motor is running. If you do, it's not uncommon for the motor to be unsteady without a load. How does it sound with the blade running?

Baymee has the right answer. Many BBC units will hunt somewhat with it off.
As I have stated many times before you can screw in the idle stop and this will resolve a lot of issues.
Do not adjust the idle jet or you may break it.

Get carb cleaner and with it running spray the throttle shaft if the idle changes its sucking air around the shaft which is fairly common on many small engines only fix is new carb. Can also dust the engine

should the mower surge after the first use? I only used it one time and now the motor surges

The main cause of surging is not enough fuel for the engine to maintain the governed setting, so it hunts. Anything that restricts fuel flow can cause this including carburetor not adjusted properly, partly blocked carburetor jets which is the same as a jet being too small, and an air leak in the intake manifold which is the flip side of not enough fuel.

Your low speed jet is set to lean , open it up quarter turn . This will richer up the fuel mixture and smooth out the idle. Many of Epa compliant models idled rough after break in .