Re: Yamaha f100 smoke when idleing
Snarl2004,
If it is smoke from engine oil then no, its not normal. You can check this by removing the spark plugs and looking for oil saturation or carbon deposits. It would be a good idea to compression test as well, or even better a leak down test. Does the engine consume much oil during normal use? It shouldn't require adding oil very much at all.
If you run the engine in cold water like I do in the Northeast it could be the steamy water coming out of the warm motor into the cold water. This would be most noticeable during idling and least noticeable when running along at a good speed. This does happen sometimes, but if you use the boat in a warm climate its probably not this.