No start

[Brapper]

After getting my boat out of storage…full fuel tank stabilized, boat
won’t start. Jumped battery to fuel pump and it pumps. Checked voltage at purple and white/red stripe input wires and shows 11V while cranking, but when hooked up no fuel.

 

[Brapper]

Oops, 1998 4.3 mercruiser with 2bbl carb

 

[alldodge]

Crank and no start
Assuming there is fuel in the carb need to check ignition system. Should have TB5 and this is the chart

Welcome aboard

 

[Brapper]

Engine fires when small amount of starter fluid used.

 

[alldodge]

Engine fires when small amount of starter fluid used.

ok, then carb is clogged up, fuel pump runs but does not pump, the antisiphon valve is keeping pump from sucking fuel from the tank, or fuel filter is clogged

When carb is pumped does fuel squirt from carb?

If no fuel, remove fuel filter (should be full) and dump contents into clear container to see if there is anything but clean gas

 

[Brapper]

Filter is new and pumps when I jump from battery…only when I hook up boat wires to pump does it no longer pump

 

[alldodge]

Filter is new and pumps when I jump from battery…only when I hook up boat wires to pump does it no longer pump

If the fuel pump is able to pump fuel, it takes maybe 30 seconds for the fuel pump to fill the carb. Once carb is filled the motor will start and run even if the fuel pump stops running for a several minutes at idle.

Your not getting fuel to the carb, so remove the fuel filter to see if it's full of fuel, it should be. If it's not full look for a air leak somewhere in the fuel system, or the pump even though it runs its not sucking fuel from tank.

If the fuel filter is not tight it could be leaking air which stops the fuel flow

If all is good, remove fuel line from the carb and place the line in a container to catch gas. Get the pump to run and see if gas comes out with pump running

 

[Brapper]

Gas only comes out of fuel line when jumped to battery…plug wires in and nothing

 

[alldodge]

it takes maybe 30 seconds for the fuel pump to fill the carb.

Gas only comes out of fuel line when jumped to battery…plug wires in and nothing

If you jump the fuel pump with the line connected to the carb for 30 seconds, the carb will be full and the motor should start

Does it start if you jump the pump for 30 seconds and then try to start?

 

[Brapper]

I will try that!

 

[Brapper]

It will probably start…pump does not run when properly plugged in with engine cranking

 

[alldodge]

pump does not run when properly plugged in with engine cranking

I understand pump does not run when plugged in, but it does "run" when you jump it, Right???

So jump it and let it run for 30 seconds.

Reconnect correctly to the motor and see if it will now start?

 

[Brapper]

I will try, but believe it will start as fuel gushes out the line when jumped.

 

[alldodge]

I will try, but believe it will start as fuel gushes out the line when jumped.

Your killing me

Reconnect the fuel line to the carb

Jump the pump for 30 seconds THIS Fills the Carb

NOW try to start

 

[Brapper]

I understand that, and thank you, but if the pump does not run while cranking that is the first problem…a gummed up carb is secondary, isn’t it?

 

[alldodge]

A carb has a fuel bowl
The pump fills the fuel bowl
If the bowl is filled prior to cranking the motor it should start and run until the carb bowl goes dry (5 minutes or so at least)

Want to find out is it the carb or something else

 

[Brapper]

I did not know that…TY! Have not had the chance to check yet