I thinking probably referring to an older Briggs Opposed engine but there the Vanguards v-twins that are around 18hp. Personally I go up in hp to something like a 19 hp at least. My reasoning is you are no longer producing power on every rev but coasting one of two rpms. Even with V twin you are coasting nearly 3/4 of a rpm. You depending on the flywheel effect during these times.
Just a personal opinion.
I would think so. mtd has put out same 42 " decks with engines from 13 hp to 17 hp singles.
Yes 38racing MTD did this low power engines on some 42" but they are gutless wonders too when comes to cutting grass. I currently a single 16.5 hp on a MTD Yard Machines 42" that has problem cutting high grass. I got an older rated 21 hp (rated 19 hp on the newer spec rating system) that I will be putting on it in a week or so just got to get to it as is going to replace a 38" that I personally use that has 15.5 hp on it . The 38" will cut just anything I throw at it though I do need to giving time on waist high grass and weeds.
I have a Noma that is 14 hp with a 43" deck
Murray and Noma both used drive pulleys that match the HP up better to the decks.
Let see what others that do more engine transplants thinks.
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