1999 115 h.p. Yamaha Outboard

Question
I noticed the lower unit is starting to discolor (turning white)right above the cavitation plate.  Is this from heat?  I recently started using a gas stabilizer on all fillups.

Answer
Hi Don....Thank you for selecting the undersigned to reply to your question.

A fuel stabilizer is usually introduced when a vessel is being laid up for storage, not during every fill-up. Regardless, it ought not to cause any harm. Fresh fuel is the important aspect, so save your money and avoid the stabilizer till storage time, and make sure your tank is full to minimize the build-up of condensation.

As for the discoloration on the lower unit housing above the cavitation plate, perhaps the exterior finnish is peeling off and revealing the primer coat. I suggest you consult a dealer/mechanic who can actually see the problem first hand, in order to obtain a professional opinion.

Safe Boating
Ron