A few issues with my OB, hoping someone can offer advice.

2005 15 HP Johnson 4 stroke.

Occasionally I get a low oil pressure warning, the red light illuminates on the front of the engine, it idles down and runs rough. Shut down the engine, restart and it runs fine. The oil level is full so I'm assuming it's a bad sensor. Would you agree with that assessment and do you know where the sensor is located?

Second issue. It often, but not always, idles rough and will stall unless throttle is increased, at high speed it's fine. Sometimes it idles very quietly and smooth. Has new spark plugs and fresh gas. Screen in the fuel filter looks clear. It can also be difficult to start but again, not always.

Thanks guys