4 stroke - Blue smoke from exhaust

[Terrylq]

My 2004 Yamaha 150 4 stroke outboard engine will expel blue smoke from the exhaust. Sometimes its the first time it is started but generally it happens about the 5th time started during the fishing trip. Very intermintent.

The smoke is cleared by increasing the throttel.

I have talked with other Yamaha owners and none seem to have this problem.

Does anyone else have this problem?

Any suggestions? I do run ring free and do not pull plugs with it.


Thanks

[Bay Catt]

Beings the motor is fairly new and the blue smoke is not always present it sounds like a fuel burning issue. The only things I can think of would be incorrect sparkplugs or plug gap, or improper voltage to the plugs. Check also for pinched fuel lines to one of the carbs. I don't think ring free would be a cause of this but then again I don't know if it has a shelf life or if it goes bad if it gets frozen. Gets pretty cold in South Dakota. Also check water/fuel seperator and the strainer for water. Is your gas tank properly vented? Whats the percentage of ethanol in your gas? Where I am at it is currently 10% but will be going to 20% soon and I am expecting problems.

[Terrylq]

The blue smoke has happened for three consective summers, about 5 times a summer. The mechanics think its maybe a drop of oil seeping down one of the sleeves.

No ethanol has been run through this motor, we can still buy gas without ethanol even though its a lesser octane (dealer recommends).

Thank You for your time and if you have any other suggestions, please reply.