Here's some pics

I'm not honestly sure as there doesn't appear to be any codes on the engine. I've seen an identical b&s engine on eBay and it was a 3hp engine. I'm not sure if that helps. Could the merry tiller major take a 5.5 or 6.5hp engine?

I've just bought a merry tiller major which runs but it seems to have an issue with the engine. Although it starts it doesn't seem to rev up and appears to be seriously lacking power. I'm considering getting another engine for it and wanted your opinions on a relatively powerful engine that I could ...