I have an old John Deere 110 (10 horse engine) that has worked great for 40 some years. As spring came this year I started it up to have it die after 10 minutes when it warmed up. After it cooled down it will start again to only to run for 5-10 minutes. I've changed the coil, the voltage regulator, the ignition switch, and the points and condensor. It still behaves the same. When it heats up the points stick open. If anyone has any suggestions, I will try anything.

MrStyx. :(

carburetor??? clean it

Oh yeah, I also had the carbarator overhauled. Today it ran 15 minutes before sputtering and backfiring to a stop.

Is it possible that you have some dirt bouncing around in the fuel tank? or
a plug wire grounding out?

MrStyx I am assuming this John Deere has a K241 Kohler engine (10hp) since it is 40 Years old. When you changed the points did you install a new plunger rod. Since you say when it quits running the points are open this leads me to believe the plunger rod is sticking.

The run time and cool down time is very consistant. Dirt and bad wires are not. I did clean the fuel lines and tank.

Plunger rod? I will now. Thanks

Hope the plunger rod will fix your problem.
After it cooled down it will start again to only to run for 5-10 minutes.

You say it is 40 years old, only half as old as I am but age does have it effects I know from experience.
Strange but after a cool down I can go for about another 5-10 minutes.

Well, I took the plunger rod out and nothing appears wrong with it. I oiled and put it back in. The same problem exists. It last for about 10 minutes and died. Are there any ideas. It turns out that the engine is a techumsi. I am still frustrated.

Remove gas cap and try it again.