Inherited 1988 searay 21 cuddy with 5.7 liter merc need help

I recent brought back the family boat my dad has been storing for years. It has been around 7 years since it has run. I changed oil and got a new battery. It ran the first time ok but only on ether. Today I tried to start it and was getting a lot of white smoke out exhaust and had some knocking from engine which was not present at first.

Start by checking the compression readings on each cylinder. Consistency between each cylinder more important than absolute readings.
How to do this has been explained on this forum many times. If you haven't done this before, search for the thread. A random post on this is:
http://www.marineengine.com/boat-fo...a-compression-test&highlight=compression+test

I'd add a few things to this post.
1) Throttle wide open
2) Fuel shut off
3) Wire from coil to distributor unplugged from distributor and grounded.
4) Crank engine until it makes 2 complete revolutions with all plugs out and see if any water comes out a spark plug hole.
5) Its easier as a 2 person job unless you have a remote start switch ( avail in any auto parts store)

iclare said:

I recent brought back the family boat my dad has been storing for years. It has been around 7 years since it has run. I changed oil and got a new battery. It ran the first time ok but only on ether. Today I tried to start it and was getting a lot of white smoke out exhaust and had some knocking from engine which was not present at first.

Click to expand...

Ayuh,.... Sounds like it ain't gettin' any Gas,.....

It's probably Knockin' from runnin' it on Ether,...