1989 Cub 1210. What to do.

[wedge40]

Got a 25 year old 1210. Been a great tractor to date. Winter in the shed, spring comes and starts and cuts grass like it should. This year not so...
Started tractor made one round and engine starts to sputter like fuel line is clogged, losses power and quits. Turn the key and it will start and I can run another minute or two.
I've drained the gas and put new in it. Same thing. I've got new air cleaner and plan on removing and soaking the carb in carb cleaner. Anything else I should be looking at.

Wedge

 

[rcbe]

get a can of rattlecan carb cleaner and keep it handy. Next time engine stalls/quits like that, quickly pull air cleaner off carb, spray cuppla shots directly into carb throat. Try to start engine. If engine "pops" or attempts to run, you have a fuel delivery problem. If not, ignition or mechanical prob.
if fuel delivery prob: (Pix/notes)remove fuel line at carb. Have catch container at the ready, if gravity feed. If fuel pump equipped, disable spark plug, crank engine to look for good flow of fuel to card. If none/poor, replace any/all fuel lines/filters to remedy. If fuel flow good/clean, proceed with carb removal, complete teardown/cleaning (including probing all orifices with small dia stiff brass wire and compressed air and magnifying glass) then rebuilt with new rebuild kit - do not re-use gaskets. retest tractor.
if still probs, post back with updated detail. Good luck.
PS: that Kohler may be equipped with a fuel filter. Make sure it is an OEM kohler filter - for that particular engine. Kohlers are know to be picky about such.