I bought a Horse with a blown 8hp Kohler Magnum, I replaced it with a 95.00 212cc Predator engine from Harbor Freight so I could use it until I get the Kohler rebuilt.The Predator engine bolted right on. The bolt pattern should be the same as your 7 hp Kohler. I have about 15 hours use on the tiller so far. The engine starts very easy and has plenty of power for the tilling I've done.I also know of someone else who put a 5 hp Briggs on his Horse, but I'm not sure if any modifications for mounting were needed, but it seems to work fine down here in the south without clay or rocks.