Question: I am about to start working on my outboard engine, getting it ready for the upcoming season. Yesterday I took the propeller off because I have finally decided to replace my beat up aluminum propeller with a stainless steel unit. After I got the prop off I noticed a bunch of monofilament fishing line wrapped around the shaft. Can this stuff damage my outboard?
Answer: You bet it can, and it may have already. Fishing line (whether Dacron or monofilament) that gets wrapped around a spinning propeller shaft can work its way under the lip seals on the shaft. Those are the seals that keep water from entering the gear case and keep from oil leaking out.
If you’re lucky you may have caught it before any damage has been done. If there is no evidence of oil leaking out, that’s a good sign. Next, remove the lower oil plug on your engine and see if any water drains out before the oil (water will always settle to the bottom). If the oil is a milky color it is too late; water has gotten into your gear unit.
If the gear unit is still working OK and not making any weird noises, you still need to get the oil seal replaced ASAP to avoid major damage to your gears.