I've had a couple of recent instances when up on plane an alarm-type sound will occur. I think it eminates from under instrument panel, but not 100% sure. I generally back off the throttle, it goes away and I get back on trottle. Sometimes, it will come back, other times it won't. It is very intermittent. I have oil in resevoir. All instruments suggest normal engine operation. Anyone have idea as to what might be going on here? It's a 2007 150 Optimax. Otherwise, seems to be running just fine. Thanks for your ideas.

Check the oil cap on the reservoir under the cowling,,i had to replace mine twice in ten years, small crack,,would do same thing. 200 optima x

Yep, check the cap and reservoir carefully and the oil level, even if it looks to be full. When I bought my boat new in 2007 (200 OPTI), the alarm would intermittently sound. Sometimes once a day, sometimes not at all. The reservoir on the engine appeared full. I finally took the cap off and topped it up with an eye dropper and no more beeps.

Thanks for ideas, fellows. Appreciate it.

Also I believe there is a throttle position sensor that could be going bad.

Took boat to Billy Sartin at Sartin Marine, Yantis, who scanned motor/on-board computer. Diagnosed water pump needed. In and out of his shop in less than 24 hours. Way to go!!