I looked at Tohatsu, Honda, & Yamaha websites. Tohatsu and Yamaha 4 & 6 HP motors both weigh about 60 lbs. Honda 5HP about the same. I recently bought a Tohatsu 6HP, fairly easy to turn over and runs perfectly. Looks like electric start starts at 8HP & up but with about a 25 lb weight gain.
Portable Specifications | Yamaha Outboards
Honda BF5 Outboard Engine - 5 hp boat motor specs and features
Discount Tohatsu Outboards and Nissan Outboard Motors