Mercury 115 hp 4 stroke 2002

meridian180

Recruit
Joined
Apr 29, 2012
Messages
3
My merc went underwater month ago. Have done everything possible to save it . Have changed coils, flushed the whole engine, changed injectors, changed fuel filters both , changed spark plugs, changed oil and filters , changed gear oil, have cleaned inside and out ,changed trim controlled. Every time I clean the fuel filters, fuel pump primary it's fires up , if I leave it for day's, it won't start . After pumping fuel it will start after a dozen tries . But stalls on running and switches off. Somedays it does 4500 rpm . Somedays nothing. What should I do next. Don't have a merc dealer near by, don't have a qualified tech near by. Have to get parts from Australia through a dealer based 2 hours by flight. Help please.
 

patbalmos

Seaman
Joined
Aug 2, 2011
Messages
59
Re: Mercury 115 hp 4 stroke 2002

Did you drain the fuel and water out of the vst houssing?
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Mercury 115 hp 4 stroke 2002

Do you have a fuel pressure gauge you can monitor fuel pressure to the injectors?

You need to see if the high pressure pump is keeping pressure up.

Listen to the pump, it should run for a few seconds when the key is first turned on then shuts off until the motor is cranked and started. If the regulator allows pressure to bleed off the motor can be difficult to start.

Once started, the pump should stay ON. If the pump driver in the ECU fails, the motor dies.

The fuel pump has a constant 12 V pwer supply, the driver in the ECU controls the ground to operate the pump, Disconnect the pump wire to the ECU and rig a new wire from the pump to ground, if the motor starts and runs fine, the problem may be the driver.
 

meridian180

Recruit
Joined
Apr 29, 2012
Messages
3
Re: Mercury 115 hp 4 stroke 2002

Do you have a fuel pressure gauge you can monitor fuel pressure to the injectors?

You need to see if the high pressure pump is keeping pressure up.

Listen to the pump, it should run for a few seconds when the key is first turned on then shuts off until the motor is cranked and started. If the regulator allows pressure to bleed off the motor can be difficult to start.

Once started, the pump should stay ON. If the pump driver in the ECU fails, the motor dies.

The fuel pump has a constant 12 V pwer supply, the driver in the ECU controls the ground to operate the pump, Disconnect the pump wire to the ECU and rig a new wire from the pump to ground, if the motor starts and runs fine, the problem may be the driver.

Thank you for responding , no don't have a pressure gauge , can I make one with psi meter? On ignition the pump does switch on and goes off until I start the engine . I will do what you have advised thank you and will let you know how it went. Iam glad I started this thread , I was in a jam
 
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