My primary mower is in the shop. Went to my backup 60" Exmark with 26efi Kohler. I have not been able to keep a charge on the battery(new). Today while mowing it began blowing black smoke and idling roughly then died and would not start or even turn over. Any ideas what this sounds like? Also, I have a pretty good oil leak from the top of the engine. Took it to the dealer today. Mechanic said oil leak looks like a breather gasket. They will call with estimate for repairs. The engine has about 2700 hrs. Definately doesn't have the power that it used to. Wondering if I should just bite the bullet and put a new 26efi on it or short block? If anyone has done this let me know. And how much was it?