Will changing a sparkplug fix a lawnmower that surges? Let's find out!

Here we have a Toro brand lawnmower with the Toro brand (Loncin) 159cc TXP engine (Honda GCV clone) that starts and then surges while it runs. In this experiment we are going to try replacing the spark plug to see if this will stop the surging.

[@Rein_Ciarfella]

That viewer is nuts or trolling you! You’re absolutely correct in your assessment, although I would add that it’s also possible for the governor arm to become loose or not be reinstalled correctly and cause surging.
As for spark plugs, I always clean them either by using a torch or my bench grinder wire wheel. If they’re still the issue then I replace, although that’s rarely the problem.

[@ukqwerty999]

Someone was talking Bo**ocks :) Because you clearly know what you are doing, thanks for the demo will do this tomorrow :) Hi form England.

[@philliphall5198]

Ok you didn’t let it run long enough need to run it for two months
lol 😂

[@machinesnmetal]

It's funny I gave it back to the customer and he messaged me yesterday and told me he didn't know what I did but it's never started and run so good since he bought it brand new 😁 I love getting reports back like that, makes all of this worthwhile

[@JimmyBombers]

What if it wasn’t that and is the main jet can that be a pain to do?

[@machinesnmetal]

The problem was the main jet I was just trying to prove a point to a viewer with that video. Very easy to remove and clean the main jet almost as easy as changing the spark plug.

[@philliphall5198]

Maybe his had very very weak coil
That is all I can think of for a new plug to temporarily fix it