Mercury 50hp 4stroke cutting out

[Dalmorloson]

I have a 2003 50 hp 4 stroke on my pontoon. From my dock through the no wake zone (about 5-10 min) the motor seems fine. After getting up to speed (not necessarily WOT) the motor starts to cough and lose power. When I squeeze the primer bulb it runs fine for about a minute then sputters again. I replaced the bulb thinking it was losing prime but no help. I hear everything from filters to pump to ignition. Does anyone have any insight as to why it runs fine at idle speed at first? After it starts sputtering it will do so at all speeds including idle. Thanks

 

[hotrod53]

Stupid question..... you do have the fuel tank vent open.... right? Fuel pump need rebuilt? Sounds to me like you're starving for fuel. Will it keep running if you keep priming it? You may also have a bad fuel line... I've heard that they can collapse internally and you won't know it. Ethanol is hard of fuel lines!

 

[Nathan Bond]

I just had to replace the fuel lines on my 2005 Mercury, due to ethanol eating up the inside lining of the lines. Which also meant the fuel filter and fuel pump were full of pieces of broken down fuel line. It was pretty easy to see by disconnecting the fuel line at the primer bulb and looking into the line with a flashlight.

 

[godblessamerica11]

I just had to replace the fuel lines on my 2005 Mercury, due to ethanol eating up the inside lining of the lines. Which also meant the fuel filter and fuel pump were full of pieces of broken down fuel line. It was pretty easy to see by disconnecting the fuel line at the primer bulb and looking into the line with a flashlight.

Nathan,
Did you rebuild pump? Do you mind providing some advice/insight to the job please?
Joe,

 

[godblessamerica11]

Nathan,
Did you rebuild pump? Do you mind providing some advice/insight to the job please?
Joe,