i dont know if you have a fix for this yet , but here you go ,
Grant steering wheels are universal and they have several adapaters.
You pick the wheel of choice and find your adapter.
If you are near an autozone, advance, oreilley sometimes they stock.
on the application chart hit year then marine etc.
good luck.
Grant
Marine Installation Kits
The die-cast aluminum 5-bolt pattern style hubs feature a textured powder coat finish, include 5 stainless steel bolts and a plastic center cap.
Model # Application Hub Type
3650-1 Marine Hub to fit 3/4" tapered shaft with keyway. 1-3/4" high. 1
3655-1 Tall Marine Hub to fit 3/4" tapered shaft with keyway. 2-3/4" high. 2
3656-1 Splined Marine Hub to fit standard splined shaft. 2-3/4" high. 3
http://www.grantproducts.com/c-198-how-to-buy.aspx