Adding a throttle and choke to a 6.25 craftsman (possible?)

Hi everybody,I have just joined the forum and this is my first post.I have a problem that is beyond my solving.
I have a 6.25 hp. craftsman (Model#917.388360)(engine model# is 143.006200)Which I am trying to use as the
engine to an outboard motor lower unit.I have done this before,it works well and is becoming a common retrofit
for anyone having an old outboard leg.Normally with an engine that has a throttle and maybe a choke this is
very easily done (checkout youtube).But the carburator on my engine has a fixed throttle.Pull the handle and off
she roars full speed.This means running full speed while shifting into forward and reverse from neutral,not a
safe or smart move.Anybody know a way to convert the stock carb so that I have a throttle (and maybe choke).
OR, another carb with existing throttle.I have no idea how one would determine if it would fit or if there are
problems with fuel delivery or other problems.Anyone have any advise?
thanks in advance, johnsella