Small Engines (Lawn Mowers, etc.): Kohler K241 Idle problems, air filter element, gilson brothers

Question
I recently inherited a Gilson Brothers Lawn Tractor from my cousin.  It was Built in 1958 and used to mow until about ten years ago when he parked it and bought a John Deere 110 to mow with instead.  We were able to get the engine running with a new battery, new fuel line and fresh gas.  It fired right up no problem.  The problem is that it will not idle.  It tends to lope(revving up and down), and then quit.  The 110 Deere that my cousin has has the same engine and it idles great.  I am sure the engine is a K241 (10 HP) it also has the old starter generator setup.  I am planning on changing the spark plug, air filter element and precleaner, and the fuel filter.  I was wondering what else could cause the engine to not idle properly.  Thanks

Answer
Stephan,

   Since it was garaged over a long period of time and was not run since then sometimes the valves stick and the gaskets dry out.
What you can do is this
If you look at the Carb while it is in Idle mode you may see a trigger moving back and forth while it idles this is the Intake Choke it will look like a small circle with a notch on it
it will be the only thing that moves freely on the carb itself.
If you advance the the throttle meaning give it a bit more fuel it will smooth out I will show you how to do that below But what is going on is this.
when it Idles the Intake flap inside the carb is moving as the engine is calling for more fuel and air when it gets too much it tries to choke out the combustion when it gets too little it kills the engine.
to adjust and give it a bit more intake and smooth it out try this
where the trottle cable connects to the Carb there is a screw ususally before the Carb.
unscrew the screw dont remove it just loosen it
take the cable and push it towards the carb throttle body about 1/8th an inch and retighten the screw while holding the cable the entire time
start it Up and see how that  works
it should smooth out the idle
what were doing is giving the engine a bit more intake
Next from years of sitting
there is a product on the market called Restore by Rislone
they make it for 4 6 8 cylinder engines get a 4 cyl container of this add only 1/4 can to the engine oil allow it to run in the engine until your next oil change
Restore does just what it says restores the gaskets and seats back to original operating order
Purchased from any auto parts store for under $12.00
this should smooth you out and make that 1958 Model run like the day it was bought