Well today, it was acting as if it were missing doing a mow. Just a slight noise change from the motor every so often during the cut

 

That honestly sounds like a carb issue. Take it apart and clean jets with carb cleaner and compressed air. Check all the gaskets make sure no tears. For it to be having this issue with only 4hr is odd. If it doesn’t stop put on a new carb with a OEM replacement. Not sure if you want to go to that expense being it’s under warranty but it’s something you can do easily and quickly.

 

I know yours is brand new but I just picked up a 2014 GM1000 with 400hrs and it had a terrible surging problem and would only run at its highest idle setting. Anything lower and it would stall. I replaced the carb and it completely fixed the issue. Since your unit is brand new maybe contact Toro and inquire about a warranty claim. Air, fuel, and spark are the only things that will make that engine surge. Spark is almost never the issue (still worth checking though), so as long as your air filter is clean and properly installed, the only other cause would be fuel/air mixture (ie. carburetor).

 

You would think these dealers would look these machines over before some pays $2000 plus. But I guess that’s wishful thinking

 

My Exmark Commercial 21 push mower has that engine. I've had it for years now, but I remember it doing the same thing when it was new. Problem self-repaired.

 

My Exmark Commercial 21 push mower has that engine. I've had it for years now, but I remember it doing the same thing when it was new. Problem self-repaired.

Several members on the forum I have read said the same thing. I’ll push through it and put some more hours on it

 

Imma knock on wood with this one. Cut a yard today, and not a single surge or hiccup