Fuel pump

[welchman]

I have a 120 merc I/O 2.5 litre.
It won/t start unless I pour some fuel in the carb once it starts I have no problems runs like a charme even if I shuit down it will stqrt no problem. I change the fuel filter to no avail. I disconnected the fuel line at the carb and turned the engine over1 no fuel! Pour some gas in the carb and away she went.
Anyone got any ideas of whats happening or not happening I guess?

 

[Don S]

Re: Fuel pump

disconnected the fuel line at the carb and turned the engine over1 no fuel!

Either the fuel pump is bad, or the pump can't get fuel from the tank to the pump do to clogs or air leaks.

 

[vxtech]

Re: Fuel pump

sounds like fuel pump diaphram is stretched and worn,-during cranking fuel pump is barely moving diaphram, but when you add fuel to carb motor instantly starts and pulsations to fuel pump diaphram are occuring rapidly creating enough flow to stay running , also check to make sure fuel is not leaking into crankcase and pump will lose prime everytime boat sits unused