My heavily modified 646 has been having heat issue ever since I stuffed a Kohler 18 horse v-twin under the hood. The problems have not been with the engine but rather the hydraulic system. When I built this rig I used an oil cooler with a smaller diameter oil passage than that which is on the tractor and that was a dumb thing to do. My return lines were of the clamp on variety and it really sucks when they get too hot and decide to blow off. My solution was a new cooler with 3/4 bore in and outlets and replacing the clamp on return lines with pipe thread hydraulic hoses. My test of the new system involved running the tiller and using it hard and I have had no more problems. To make this critter fit I extended the hood on my tractor by three inches with the thought of adding an electric fan if need be to the cooler. The hood modifications turned out better than I would have expected and only a trained eye or serious Case prude will ever no the difference.
Edited by Case-Closed, June 01, 2014 - 10:29 PM.