My 1972 140's engine is noisy. plus it's hard to steer. So I'm thinking of killing 2 birds with one stone by installing a new light weight, 2 cyl. engine. I know there are a couple of companies that sell kits that includes the engine of your choice. It looks like most people go with a 18 HP B&S.
I would like to hear from people that have gone this route, their thoughts, recommendations and hopefully some pictures of the project.