Fuel mercruiser 3.0

[roadkingba]

I have a 1988 merc 3.0. Does not want to pump fuel unless I pinch off return line to tank. Is this indicative of a bad fuel pump?

 

[Scott Danforth]

the 3.0 in 1988 would not have a fuel return line to the tank as it is a carbureted motor.

there are 3 connections to the fuel pump. the inlet port connected to the filter (tank), the outlet port connected to the carburetor, and the 3/16" tygon vent line to the carb throat in the event the fuel pump diaphragm ruptures.

 

[roadkingba]

the 3.0 in 1988 would not have a fuel return line to the tank as it is a carbureted motor.

there are 3 connections to the fuel pump. the inlet port connected to the filter (tank), the outlet port connected to the carburetor, and the 3/16" tygon vent line to the carb throat in the event the fuel pump diaphragm ruptures.

Yes it is carb. This line comes from separator and appears to go back to tank.

 

[roadkingba]

the 3.0 in 1988 would not have a fuel return line to the tank as it is a carbureted motor.

there are 3 connections to the fuel pump. the inlet port connected to the filter (tank), the outlet port connected to the carburetor, and the 3/16" tygon vent line to the carb throat in the event the fuel pump diaphragm ruptures.

 

[roadkingba]

Tried to send pic.

 

[Scott Danforth]

Your fuel water separator should have 1 inlet port connected to the tank anti-siphon valve, and one port connected to the fuel pump.

some installations where a kicker is added, a second outlet can be connected from the fuel water separator to the kicker. these can be problematic as the fuel pump on the main motor can pull air from the kicker fuel line.

 

[roadkingba]

Tried to send pic.

Your fuel water separator should have 1 inlet port connected to the tank anti-siphon valve, and one port connected to the fuel pump.

some installations where a kicker is added, a second outlet can be connected from the fuel water separator to the kicker. these can be problematic as the fuel pump on the main motor can pull air from the kicker fuel line.

That was helpful! It once did have a kicker hooked up that I don’t use. I can plug that. Thanks!

 

[roadkingba]

Yes it is carb. This line comes from separator and appears to go back to tank.

Thanks for the help. It was going to outboard, I plugged it.