Well, try it out! If it has an operating engine, doesn't rap, runs and drives, and digs and plows, thats about all you can ask for! If it looks nice, seems to have been taken care of, not left to set out in all kinds of weather, has all of its main parts, those things are a plus! I was given one that had set in an old shed, with a busted connecting rod, a dead battery, two flat tires, and a total lack of care! With a new con rod, and a lot of work making it run, I sold it to a friend,for $250, who is still using it, 7 years later! Are you sure it is a Troy-bilt? I think MTD is now handling them, for parts.

For me, the hands-down winner would be the Honda over the Briggs. As it happens, it's even less expensive to buy. Your tiller is geared down to drive the tines at less than 10 percent of the engine's speed at wide open throttle. That means the torque and hp of the engine are more than ten times greater as far as the tines are concerned. If your old engine did a good job when it was new, then there is no real reason to increase the hp because all you are increasing is the amount of fuel you will burn each time out. If you find those engines too expensive, you might want to consider a Honda clone from places such as Harbour Freight. After all, most people don't even put ten hours per season on their tillers.

Friend had a 7 horse kohler "K" I think it was. It was on a cub tractor with a 42 inch 3 blade cast deck. Delco starter/alternator and a button clutch. Must of been early 70's. Anyway I short blocked it and boy did that thing run. I'd look into rebuilding what you have. That is a great engine. Peace

Follow up to my own post. I think I misinterpreted the function of the throttle. It makes more sense to say it admits more air to the intake, which sucks more gasoline (or propane) in for acceleration. The governor, connected to the throttle also, does the same thing to maintain a constant speed. I do notice a lot of posts dealing with carburetor and gasoline problems. Many of the responses advise rebuilding the carb, using carb cleaner, cleaning jets, even getting a whole new carb, and throwing out stale gas. Also cited are possible seal deterioration from ethanol, and other problems/solutions. I am surprised more people don't try the propane option. By the way, there are several manufacturers of conversion equipment, some of them much cheaper than Altfuel. I only went with them because other websites were almost impenetrable to navigate, and confusing when trying to figure out whether their system would work with my situation.