Merc Outboard 135

Question
Mr.Marine
Recently purchased 1994 SeaRay with 135 Merc Outboard
The Power Head was replaced in 2004/2005 with factory rebuild  (stickers on Power Head)
The engine does not want to start at all times--cold-hot--does not make a difference--when it does start--lots of smoke--blue at times--some times black
When no start occurs, no spark at 2 plugs--did not check others
I would like to start testing other parts--first the teather switch and then .......
Do you have a wiring diagram and specs for electrical system?
I have most trouble shooting tools and eqp--from DVOM's to digital o-scopes

Answer
Hi Randy

Thank you for selecting the undersigned to respond to your question.

I'm not a mechanic Randy, but it sounds to me like you might have a serious problem on your hands. Any idea who installed the rebuilt head...previous owner or a certified marine mechanic? Usually there's a limited warranty involved, so first, I'd explore its term and benefits. Have you consulted a local Mercury dealer to acquire a copy of the wiring diagram? They may be nice enough to photocopy one for you.

The color of smoke suggests the amount of oil mixed with the gas may be of excessive proportion or too rich a mixture, so follow the manufacturer's recommended ratio. Perhaps too much fuel is being introduced and an adjustment is required. Or, you may find a ring or two might be broken, allowing some oil to pass up to the top of the piston, hence, black smoke.

Did the color, residue deposit, or odour on the spark plugs give you a hint as to what might be the problem? It could be the timing needs adjustment.

Obviously, there's an electrical problem, and you'll simply have to trouble-shoot that to determine where the malfunction/failure is occurring and why.  

That's the best I can do Randy.

Safe Boating
Ron Blanchet