Alarm horn @ 4600 rpm

[Bilgewater]

Have 1987 Johnson 150 hp 2 cycle engine. At 4600 rpm the warning horn goes off. I can throttle back a few 100 rpm and the horn will silence. I have replaced all the fuel hoses primer bulb and cleaned filter under the hood. I have an in line fuel/water separator that is 10 micron. Could this be restricting the fuel flow to reach WOT at approx 5000 rpm. Other than this motor runs great.

 

[racerone]

Is it a solid alarm ?----Have you replaced the water pump impeller ?----Running with VRO in service and tested ?----Yes , it could also be the fuel restriction alarm.-----Try bypassing or taking the 10 micron filter out as a test.

 

[saltchuckmatt]

Have 1987 Johnson 150 hp 2 cycle engine. At 4600 rpm the warning horn goes off. I can throttle back a few 100 rpm and the horn will silence. I have replaced all the fuel hoses primer bulb and cleaned filter under the hood. I have an in line fuel/water separator that is 10 micron. Could this be restricting the fuel flow to reach WOT at approx 5000 rpm. Other than this motor runs great.

Or spin the fuel filter out and dump it into a jar and inspect. Never know what gets pumped into your tank from the station.

 

[oldboat1]

Overheating (160F +) can destroy the motor. Get an infrared gun (temp test at top of heads). Lack of oiling will likewise result in overheating, but likely more dramatic destruction, particularly at WOT.