SO I replaced the engine my old Troybilt Horse today. The old Tecumsah is 41 years old and quite tired. Put one of the $100 6.5 hp Harborfreight Predator engines on. Easy swapout . Only difference is that you need a 5/16-24x 1-1/2" bolt for the reversing wheel on the end of the motor shaft. Started right up on the first pull and definitely has more power than the old engine. I need to pull the low oil sensor as it will shut the engine off at times. I could have rebuilt the existing engine but for the price the HF engine is hard to beat. I can buy 2 or 3 for the price of the rebuild. I have one spare now and I am going to grab at least one more this weekend. So if you have one of these tillers grab one or two of these engines as spares.