Beautiful day in So Cal today and decided to take the boat out. It has been running perfect every time until now. idled perfectly out the main channel and began to throttle up. Over 1,000 RPM, I get an alarm and the ECM brings on the funk. Ran horribly, dropped back to idle; alarm shuts off and runs perfectly again. Tried a half dozen times to get on plane. same results each time. Shut all power down at the Perko switch and powered up again; problem returned every time.
2006 Mercruiser 496 w/Bravo 1 - 70 hours on it
Fuel = full
Alternator = 14 V
Temp = approx 165 degrees
Oil pressure = 40 psi, full level
Trim = 80% down,
Outdrive fluid level = full
Trailered it back home, washed the boat and flushed the outdrive and trailer. With the muffs on and, started it up to recreate the problem. Lots of water flow through the exhaust. Idled perfectly. Went to 1,500 RPM ran perfectly. Slowly increased RPM to 3,000 still ran perfectly. Repeated this test at least three times and could not recreate the problem.
Any ideas what might cause this? Saw in another thread that the shifter sensor might cause a similar problem, but in the 3,000 RPM range. Could this be the cause? Time for a trip to the shop?