I have an Evinrude 70 hp Model # 70873C. I believe its a 1978 model. I'm trying to purchase a new prop for it. How do I tell if it's a small or large gearcase?
I think the large gearcase has a set screw beside the water inlet on the lower unit. Where the smaller gearcase does not have that setscrew beside the water inlet.
If you have the standard 20" midsection, the prop is a standard V4/70 hp prop. If you have the short shaft (15") midsection, the prop required is a 50 hp size prop.
Thanks for the information. My case for the 1978 evinrude 70 hp model # 70873C is the large case. The outside of the housing measures 4 1/16 " which is the large gear case.
Another reference point the small gear case has 4 water inlet holes and the large gear case has 3 water inlet holes.
