I don't have an answer to your ?......
Two things to watch on the old horse model with the Tecumseh engines
1. the carb stick way out on them and if you bump a fence post or something it'll break right off...sometimes your lucky and it only breaks the cast aluminum in the carb.....other times it breaks the cast iron on the block......I always told the customer to buy a bumper for the Tecumseh powered tillers......best $$ they ever spent to keep problems from happening..
2. make sure you keep it full of oil.....maybe just a tad over full.....when you sink them in the ground, the engine is way off of level and the oil runs to one side.......and if your low on oil.....count on a new short block......we used to call them rod slingers....
Now, this does not mean I'm bad-mouthing your tiller....they are great tillers and last for years........but I worked at a Troy dealer for 7 years and I can't tell you how many times people fell over when I tole them the carb was $70 and worse if the block broke.........then I also recall we always kept short-blocks for that particular model......because of slinging rods.....most people never have a problem.....