1988 3.7l inboard stern drive mercruiser engine will not start. Have tried everything.

[Samson1234]

Engine wont start on my 1988 mercruiser 3.7L. I've replaced the starter the slave solenoid, spark plugs, rotor, distributor cap and can't seem to make it turn over. Seems like it wants to start but it only turns. Not sure if I have bad gas. Sucked out a pint and let it settle, it was yellow with a very small layer of water floating on top. A friend said to clean the carb and check the timing.
Help please! Thanks guys

 

[emac]

Empty entire tank of gas, sounds like its gone bad, and your're in the wrong forum.