Yamaha 150 smoke/smell on startup after heavy tubing

[YellowJacket1956]

I have a Yamaha F150 on a 22' Bennington tritoon. There are 115 problem free hours on this freshwater boat. Saturday we went tubing and I was pulling two larger fellows, running between 4,000 and 5,000 rpm. The next riders were two small girls at much slower speed. No problems, and we returned to the dock. An hour or so later we started the boat and had grey smoke and smell for 10-15 seconds, then ran fine. No smoke or smell on subsequent start ups. Any idea what happened, or if I damaged anything?
Thanks for any insights.

 

[99yam40]

Did you tilt the motor at shut down or leave it all the way down before the smoke

 

[YellowJacket1956]

Normally, I tilt it up out of the water, but knowing we were heading out again I left it down.

 

[99yam40]

if left down , the oil can pool and leak past the rings into the combustion chamber where it is burned off at start up.
If tilted even just slightly it will run back into the crankcase

 

[YellowJacket1956]

Thank you! This may well have been the cause, for I have had no issues since, and engine runs fine with no symptoms of any ailments.