My 60 has run fine for over 4 years. Now suddenly rev limiter keeps rpm bouncing between 2800-3000. When key is initially turned on all four lights - check engine, rev limit, oil, temp - light briefly and buzzer sounds for 3 seconds as always. Engine starts fine and runs smooth until approaching 3000 rpm and then rev limit kicks in but none of the lights indicate problem. Changed oil and flushed engine just to see if it helped. Did not. Tell tale water stream is cool. Any one have any ideas?
