Steam out back

[Kiwi Phil]

Mercruiser 305 228hp Serial No 6260005 1984 powering a 25' Flybridge Cruiser.<br /><br />I have had the boat for 6 months, and have always been the driver.<br />Last time out the wife was driving and I was sitting down the back, watching the wake etc (day-dreaming actully).<br />There is a white odour-less smoke/steam coming out the back, from under the water (I think), on port side (I think).<br />The boat was doing 3,500rpm.<br />When we reduced the speed to 2,000rpm there was no sign of it.<br />The water temperature needle runs dead centre of the green at 2,000rpm, and increases slightly at 3,500rpm.<br />I am not using any oil.<br />There is not a drop of water in the engine bay.<br />The engine starts perfectly, and runs smoothly all the time.<br />It had 2 new manifolds fitted 6 months back. I was going to get them tightened/checked when the boat comes out of the water next month.<br />Is this smoke/steam normal, is it just atomised water.<br />Could anyone give me some advice on this matter please.<br />Many thanks.<br />Cheers<br />Phillip

 

[WillyBWright]

Re: Steam out back

Keep an eye on the temp gauge and have the water pump rebuilt when it comes out. It might be getting weak. It sounds like the motor is cooling okay, but there might be less excess water flow to cool the exhaust. Or it might be perfectly normal. V-8s produce a lot of heat when they're under load.

 

[fireship1]

Re: Steam out back

Hello, Check to make sure that you are not getting water into the engine from the exhaust. I see in your post that the manifolds were changed. Were the risers? You need to check to make sure the risers and riser gaskets are not leaking. Also need to make sure the exhaust manifold gaskets are not leaking. Steam usually means water is finding its way into your hot exhaust system. Remember water and exhaust gasses are sperate in the manifold and riser. They only come together after they leave the riser. If they find their way into the hot areas of the motor steam will result. Constant water ingestion is big trouble for the engine. Be sure to check this out before running the boat. Bad exhaust will cost 'ya in the long run. Hope this helps! Good luck!

 

[Kiwi Phil]

Re: Steam out back

WillyBWright and Fireship,<br />Many thanks for your assistance.<br />The problem was leaking gasket, infact all bolts needed to be tightened.<br />I don't understand mechanical things, so got a mechanic to fix it.<br />We took it for a spin and the problem has been solved - everything running perfectly.<br />I appreciate your assistance. Many thanks<br />Cheers<br />Phillip

 

[fireship1]

Re: Steam out back

Phillip, Glad to help out a fellow boater! Glad everything worked out for you. Thanks for the thanks, I appreciate that!