1999 215 express cruiser smoking at idle

[karmatattoo]

I have a 1999 215 express cruiser with a 5.0 mercruiser and an alpha 1 outdrive with about 220 hours on it. i am the second owner of this boat and dont know if the owners before me tool it out in the ocean. i boat in fresh water now.
anyway i have been having trouble with my boat smoking when i am idling or riding slow. i recently rebuilt the 2 barrel carb and changed the plugs yesterday and it is still smoking. when i bought the boat it had 187 hours and that was at the beginning of this season. this is the second time that i have changed the plugs and when i pulled them they were black. i have gotten everything running right except for the smoke problem. it is a white smoke. i know engines pretty well and black smoke is gas and blue is oil. it is def white and i do check the oil before we go out every time and it isnt burning any oil at all. i think that 220 hours isnt alot to have it smoke like it does. some people on iboats said that it could be the manifolds and risers. could that be the case? what could cause them to go bad so soon and what am i looking for when i pull them? please help because i would like to see how much i am going to have to put into my boat or should i sell it.does anyone know of a place that i could save some money if i have to purchase new ones? i would really love to put some thru hull exhaust on my boat. i love this boat and want to get it going right. thanks in advsance for your herlp

 

[CliffA]

as you likely know 'black' plugs usually indicate the engine is burning oil...and as you said normally that produces a blue smoke....but you said the smoke from your engine is white so this is at odds with each other....are all 8 plugs black color?...are the plugs wet with either oil or water?.....or are they just full of built up balck 'crud'?....did you happen to recently use any fuel or oil additives like 'engine flush'?.....if so the additive could have broken up all the carbon that has built up on top of the pistons over time....and now this 'crud' is mixing with the fuel in the combustion chambers and the plugs are trying to burn it...this could cause the plugs to foul with 'black' stuff...this could also produce smoke but i am not sure if the color would be white....from your description it sounds like the smoke stops when the boat is running at higher RPM's.....i don't have an idea about that if this is true.....the suggestions from the other forum relate to the possibility that water is getting into the cylinder combustion chamber through a faulty exhaust system...water will vaporize and produce a white 'steam' or smoke from the exhaust when this happens....but this would actually have just the opposite affect on the spark plugs from what you are experiencing...normally when a plug vaporizes water the plug tip will be 'steamed cleaned' and look like new....not be black like your plugs.....water getting into the cylinders is not a good thing as this can cause the engine to hydrolock and would likley require replacement due to damage to the engine internals...but the fact your plugs are black does not match the normal signs of an engine that is trying to burn water....but since you are seeing white smoke you should definetly check out the exhaust components to be sure....you may have to remove them for inspection...lots of archived post on this forum how to check the exhaust components for problems...


IMO the 215EC is a great 'all purpose' boat...we love ours....don't give up on it yet....

good luck...

cliff

 

[fatcatone549]

I have the same thing. My motor is brand new factory complete. it has 3 year waranty.I have 2 years left,so I would like to get to the bottom of this.

 

[fatcatone549]

Not only is motor smoking at idle,it leaves a oil slick on top of the water only at idle,could it be unburnt gas

 

[scoflaw]

You have the old style exhaust manifold/riser setup, pre dry joint. Even if that isn't your problem, you should pull an elbow and riser and check those joints. That's the weak point of that setup and a water leak there can kill your engine.