Your Elto Cub was one of the lightest outboards ever built, and will not stand up to much abuse. Built to be light weight weight and inexpensive, most have broken the skeg off the lower unit. The small magneto had to be in top shape and piston skirt ware could reduce its power to only running the water pump. A few thousandths would be enough to do them in (As a percentage of piston diameter) They were good on a canoe but only good for trolling on any sized boat. You paid a little more to get the Evinrude Mate which had side covers.

There are several ways to get parts.

– You can post a “Wanted” ad for parts on the classified board here. The ad is free.
– Search the classified ad board for parts.
– Search E-bay and Craigslist for parts or a “parts motor”.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR1.TRC0.A0.H0.X%22elto+cub%22.TRS0&_nkw=%22elto+cub%22&_sacat=0

– Contact a place like Twin City Outboard – an outboard junkyard that has motors going back to 1906 – they will mail parts
http://twincityoutboard.com/
– There are some members that deal in parts for these old motors. If you post a “wanted” ad, they will likely contact you. Once you deal with them, keep their name and contact info.

Most of these old motors need little or no parts – just a lot of TLC.
Good Luck!
Dave