Hey Jason
I've got a 150 Optimax. Its been in the shop for misc issues, but probably the most irritating problem was the oil reservoir. The float found in the reservoir under the cowl has a tendency to stick....a lot. Also, the screw top o-ring doesn't alway provide a good seal so when the float doesn't stick, the seal will leak. Sometimes, both issues simultaneously.
I've had to take mine in for issues related to that damn resevoir 3 times.

Now to be on the safe side, I carry an extra oil reservoir in the boat.
On the plus side, I'm very satisfied with the fuel economy.
Shoot me a PM on either board if you have any questions.
tommy