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2005 Mercury 40 EFI 4-Stroke white smoke

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Clevetex1

New member
Hello. I am new here and hoping someone can help me. I have a 2005 merc 4 stroke 40hp EFI that has 185 psi in all 3 cylinders. It has 213 hours. It starts up and idles with 1 bump of the key. No smoke at idle. But when you attempt to accelerate it slightly Boggs down and blows WHITE smoke out of the exhaust. It is not steam. It does not dissipate it lingers around. I tried changing the head gasket and valve stem seals with no luck. To me it kind of smells like fuel but I could be mistaken. I have run out of options. Please help. I don't think it can be the rings. I have had the head off and all 3 cylinders looked the same. I don't see all 3 oil rings being bad at the same time with 213 hours on the engine. Has someone else experienced this ? If it helps. From what I am told these motors were produced by Yamaha and are identical to the models Yamaha put out.
 
Did your cylinders looke rally shiny and steam cleaned? You say it's not steam but have you ever seen a car with a blown head gasket? It's not like steam from the kettle, more like thick dense clouds of smoke that hang like fog.

Have you checked your fuel pressure? Are you getting any beeps from your control box? I would also try draining the fuel out of the VST and putting it into a glass jar to let it settle for a day, just to make sure there is no water in the vst tank. Another place water could (theoretically) get into your fuel is the fuel cooler that is on the side of the vst tank. Both the fuel and water circulate through separate circuits (to keep the fuel cool) and if there were a perforation in there the two could mix. (This is all speculation as I'm trying to figure out how water could be getting into your combustion chamber.)
 
Yes I have looked at the cylinders. They do not appear to have been steam cleaned as some would put it. But I have not checked the fuel pressure or the vst. Or the fuel cooler. That I will do. Also the oil pressure is reading 57.7 psi at idle
 
How does your oil level look after running? Does it smell like fuel at all or just oil? If the mechanical fuel pump diaphragm blows it will allow fuel to leak into the crankcase. Not good!!! Just give that a check.

Where are you checking the oil pressure at? I am not sure the specs on that.
 
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