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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16108
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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Have mercury 50hp four stroke outboard warning alarm comes

Customer Question

have mercury 50hp four stroke outboard warning alarm comes on then engine inhibited until i back off revs
have checked water flow at back of engine - is fine
have topped up engine oil - is fine
I have already replaced the oil pressure and the temperature sensor. The alarm used to be a single blairing tone. recently it has switched to an intermittent beep.
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.
Hello my name is ***** ***** am I speaking with?
Can I get the serial number on the engine please.
Customer: replied 2 years ago.
I don't have the serial number with me right now. My Father bought the pontoon new in 2002, but it was at the end of the season so I am not sure if the motor is an 02 or 03 but it is a 50hp four stroke Big foot with EFI
Expert:  Jason replied 2 years ago.
Being EFI the engine needs to get hooked up to a scan tool. Has that been done?
Customer: replied 2 years ago.
Honestly I am not 100% sure I have been chasing this problem for 5 years had it in 4 different times and they do not fix it
I have several thousand dollars in it and it hasn't ran in for everThe first time I took it in they blamed it on over revving and put a different prop on it, replacing the factory prop
the second time they said fuel pump and replaced one of them
third time they replaced the other fuel pump
then thermostat and temp sensor
I replaced the oil sensor and verified the oil pressure myself this year
Expert:  Jason replied 2 years ago.
If you brought the engine to me I would hookup my laptop to it. Run the boat. And duplicate the problem. If the alarm starts beeping a code will pop up. If no code pops up then either the ECM is bad or there is a short in the harness.Thats how the process goes. Does that make sense?
Customer: replied 2 years ago.
Makes sense so am I just taking it to idiots cause 5 years seems like a long time for them not to be able to figure this out!
sorry just frustrated!
Expert:  Jason replied 2 years ago.
Anybody who is Mercury certified would have 1 of 3 scan tools. Diacom, DDT, or CDS. All of which will work on that engine. Diacom is the better of the 3 and what I use. And to be honest, it shouldn't be this hard to find. Have you been working with Mercury dealers or knuckleheads on craigslist?
Customer: replied 2 years ago.
Mercury dealers 2 different ones at that!
Expert:  Jason replied 2 years ago.
Has it been back since the latest time the alarm has gone off?
Customer: replied 2 years ago.
The alarm changed this weekend so no
but it has had the same solid alarm for all of the 5 years any time we run it over 3000 rpm for any period
Expert:  Jason replied 2 years ago.
Solid alarm is engine overheat or low oil pressure, or if the engine thinks there is because of a short circuit or a faulty sensor.
The intermittent alarm is a bad sensor issue. And any one of the sensors on the engine would cause that alarm. Think of the alarm like a check engine light in a car.
Customer: replied 2 years ago.
is there anywhere I can get a diagram with all of the sensors? the 2 I have replaced did not fix it
and I know that oil pressure and temperature are fine because I have manually checked them
Expert:  Jason replied 2 years ago.
I can definitely get that to you if I can get that serial number. There are so many different versions of these engines and I don't want to guess and give you the wrong one. So if you can get me that serial that won't be a problem.
Expert:  Jason replied 2 years ago.
Hello, just checking in. Any luck on that serial number? No rating has been put through yet so I wanted to see if you had any more questions on the issue? -Jason