I would be very surprised if MTD is actually tooling up or manufacturing "thier own engines". It's more likely that they have contracted with a chinese manufacturer to build engines for them.
Not necessarily a bad thing as most of the "American Made" tractors use imported engines. It's time to understand just how far you have to go to avoid chinese products. It's really an issue when you think about parts and parts networks. The more engines out there implies a bigger demand for parts, a bigger demand means an rising market and hopefully supplies will follow. You don't want to get caught in the void that may arise when Briggs see's the light and works out the cost issue's with the mower manufacturers and your stuck the "bastard model" with the "wang sung" engine. (I just made that name up...wang sung:laughing
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It might be a great engine...and it might not, why take a chance?