smoke question

[George Kornreich]

Hi, Gordon,I have a VolvoPenta MD22L on my Hunter 430. There's quite a bit of blue smoke on startup (I'm convinced it's excess fuel rather than oil), which almost quits when it warms up, though there's always just a hint of blue in the exhaust. From what others have posted on the forums, "they all smoke like this". One person apparantly even had an engine replaced under warranty with no change in smoke output with the new engine. Well, my question is whether this is really normal and acceptable, or is there something out of kilter in the fuel injector system? I recently dumped all my stale fuel, cleaned the tank and replaced the fuel... much better RPM, but still ole smoky. I realize that it's possible that there are a lot of boats out there with similar problems for similar reasons, so to hear that so many have noted the same smoking does really not assure me that all is well.

 

[Gordon Torresen]

Ole smokey

Light blue smoke is usually associated with lubricating oil. The cylinder walls are lubricated below the pistons on every stroke. As the piston is driven down on the power stroke, the lube oil that was not wiped down by the oil ring is exposed to a major conflagration. More of this residual oil is there when the engine is cold and diminishes as the pistons grow to fill the cylinders when they warm up. Volvos seem to have more of this bluish smoke. Perhaps it is because the cylinder walls are better lubricated. New engines frequently smoke more and it is suspected that there is more oil on the cylinder walls because it is contained in honing marks that usually disappear after break-in. I think this all means that a little smoke is OK and probably good. I wouldn't let what you describe make me too nervous.

 

[George Kornreich]

Thanks, Gordon

You cetainly set my mind at ease. BTW, I guess I had it wrong... I thought blue was fuel and black-grey was oil. Now, if I can find my "send" key through the smokey cloud, I'll send this to you <g>George