kubota

My old Kubota with the 15 hp Kohler became almost impossible to start. For a year we struggled with getting it to fire strong enough to overcome the compression release. Once running it was powerful and ran normally. Then, getting it ready for this summer's mowing I could not get it to start...

Has a Kawasaki fr 651v engine. new fuel, spark plugs, new fuel line and carburetor and fuel with filter engine surging and when I engaged the blades it dies. any idea what it could be?