Husqvarna YTH21K46 Engine surges, hunts.

[gbrewer]

I've done all the stuff. New carb gaskets, new exhaust gaskets, new sparkplug, fresh gas, new fuel filter.
Engine starts well, then begins to hunt. Governor lever cycles back and forth. I adjusted the gov setting but problem
continues. Carb has no fuel or other adjustment screws but one on top that doesn't make any changes to engine speed.
I'm open to any and all suggestions. thanks

 

[Douglas Lee]

Can you provide the numbers/ make, model on the engine
How does it run under a load?
Thanks,
Doug Lee
*

 

[Auto Doc's]

If the fuel lines are old and rigid, I recommend you replace them with a quality brand Old line will collapse internally.

Also check the fuel tan outlet nipple for any trash caught in there.

From there the carburetor is suspect.

 

[gbrewer]

It's fixed. Found that the adj. screw for low idle bottom left on rear of carb was MISSING. I had a carb that came in a repair kit; so, I replaced the carb again and all is OK.
Numbers: Husqvarna YTH21K46 Mod. 960450026 01, Ser. 063011A021729. Engine: Kohler SV610 3213 Ser. 4113815753 21H.P.