JD 325 engine problems

[jdjdad]

When my 325 gets hot it dies or if you shut it off it will not start until it cools. It has no spark . so I figured it was the coil. I bought a new coil and replaced it and still no spark. I put the old one on and it has spark till it gets hot. I thought I maybe got a bad coil so I returned it and they gave me another one, same thing it has now spark, I cleaned the terminals and still no spark, but I can put the old one on and it works.. just till it gets hot.. anyone here can help me... thanks