Hi,

My starboard transmission on my 405 is noisy. After reading all of the great posts here, I decided to start with the engine and make sure it is running right before proceeding further aft. I replaced the cap and rotar and the replaced the plugs. I made little wooden rack so I could put the removed plugs in the correct sequence for inspection. After removing them I found a website that offered pictures of spark plugs in various conditions. (after removal). Obviously from comparing mine to the pictures, all are showing rich. They are basically black and smell like fuel.

Now, what might be the cause of black smelly plugs? I have read that things like fuel injectors, throttle body, wrong plugs, wrong gap......and various other things. We have owned the boat for about six months and are fixing things one at a time.

The engine runs and idles OK, although our marina mechanic says he can feel it vibrating when he puts his hands on the risers.

All ideas are welcome....thanks