I checked 5 sites, even tried NAPA. No one seems to have the float for the 1970 40hp. Also no luck finding a carb kit with a float.<br /><br />You may be better off calling a dealer and ordering one.
The float comes included with the factory carb repair kit which is probably under $20. The float by itself normally is not a stocked item at a dealership. You need the gaskets and other repair parts anyway when you open up a carb, get the kit.
Try e-mailing this guy benren@mhcable.com He may have the kit. If he doesn't try featherweight outboards. they have a website. Both of them carry alot of NOS parts and kits.