I've had a bit of trouble with my 225 Opti. Its a 2007 and I haven't been able to get it on the water as much this past year. It will sat around a month and a half at a time. I took it out in early June and as I left the slip had the three beep warning. Ended up loading it up and taking it to the shop. They didn't replace anything just bled air from the on engine tank. Ran regularly all summer with no issue. It sat for the month of October without being run. Two weekends ago I took it out and got the three beeps for maybe 3-4 cycles of three beep and two minute wait. Then, it stopped and motor ran fine. Last weekend, it did the same but the beeps kept occurring the entire boat ride. Boat ran fine though. I pulled the cowl off and the on engine oil tank was about 90% full. There was about a 1/2" of air on top. I started the engine, opened the cap, and nothing happened. The tank didn't fill. I replaced the cap and killed the engine and tried again. The tank then filled until oil started coming out the cap. I didn't run the boat after this just ran out of time.

My questions are: 1. Should there be any air in that on engine tank or should it be filled to the overflow cap? 2. Should I be concerned that the tank didn't seem to fill the first time? 3. How fast should the tank fill? Once it started to fill, It took maybe 4 seconds to fill the 1/2" of tank.

Thanks,

Check your main oil tank cap for tightness and cracks. Mine (2005 Opti) had a hair line crack on the external tank fill tube. Easy way too check is with spray bottle of soap/water. Start motor, spray solution around cap and look for any bubbles.

bleed the air until the oil starts to come out. Sometimes it takes a little time for it to start filling. The cause for the air is usually due to running the oil level to low in the main reservoir. Once you fill your main reservoir up and bleed the air from the motor mounted reservoir you should be good to go.

sound like the float in tank may be giving you a problem might need to replace oil tank on motor

Boatman is right...sounds like same exact deal mine did to me. It was the float and/or sensor in the small internal tank.
Replaced the tank and all was good...never had another issue