No I wouldn't go for it! What's the blokes number?
I haven't seen a Ribcraft 5.85 that cheap before, even if it did have a damaged tube. Is it repairable or complete new set of tubes? If repairable then subject to everything else I would guess it's a bargain. Force isn't the outboard of choice for most but if it gets you on the water! Just remember if you replace the outboard you won't get a very big PX for a Force.