Electric fuel pump on carb motor

I have twin 5.7/350 carbs, mechanical pumps. I replaced both pumps in 2016 and overhauled the carbs. If the boat sits particularly after running o while (hot) carbs will tend to boil off the gas and the bowls will be low or dry after a few days. They will need to be cranked a good 30 seconds to refill, then pause, pump once and then they will usually start right up.

Carbs will never start as easy as your MPI after sitting, just one of the advantages of fuel injection.
Before assuming a pump issue check the carbs over (especially if it runs well after starting and at WOT)
Yes, you need the choke to be working properly. Remove the flame arrestor, be sure its clean. Cold check that the choke sets properly with one pump of the throttle. If not fix that first. When you pump the throttle be sure you get a nice spray of fuel if not the bowl could be dry or the accelerator pump could be worn out. Crank it a bit to be sure the bowl fills up and try pump again.

The electric pumps for carbs are not usually finicky. They should be specifically for carbs, low pressure 5-6 psi only no more.
Now it may depend how the previous owner wired it. If straight to the ignition it should cycle with the key. But unlike a car or MPI where the computer controls it, it may run continuously. If a relay or oil pressure switch is in line it may only pump when the engine has oil pressure and/or when actually cranking. In a boat this is the preferred safest configuration. So it will not keep pumping if the engine fails to start or if it shuts down for any reason even if the key is left on.

 

Does the fuel pump run when you turn the key on without cranking the engine. There should be a relay that would run the pump for a few seconds. That may be bad.

 

The no start issue is most likely caused by the choke not fully closing. It should snap shut when you advance the throttle off of idle.
As for the electric fuel pump running when the key is on, go back and review @hughespat57 posting and get that pump wired properly. The last thing any of us want to hear is that your boat burned down.

 

First if the fuel pump is wired to the coil that is bad. Depending upon the year but most coils have a resistor in the "run" mode and the resistor is bypassed in "Start" mode which if trying to also operate an electric fuel pump will compromise both. Secondly, the Pos wire to the coil isn't rated for both the pump and coil so there is probably a significant voltage drop regardless of the resistor. You may not only have a fuel pump issue but also an ignition issue with that setup.
Secondly, there is a choke cold choke setting which is usually a drill bit size that the choke blade is adjusted down to. Do not crank the choke thermal housing to fully close the choke blade - you will flood the engine and again have hard starting issues. With a cold engine the choke blade should be closed to the prescribed setting then when the engine first starts the choke blade will modulate depending upon how much air is flowing by it. Then over a few minutes the electrical current on the thermal housing will fully open the choke.

 

My 185 was carbed with an electric fuel pump, a little finicky, but here is what worked for cold starting.

Assuming it is wire correctly with the oil pressure switch.

1. Crank engine for 5-10sec until warning horn stops - this fills the bowl with gas.
2. Put in neutral and pump thorttle 2-3 times, bring throttle to 1/3 open - this squirts gas into intake and sets the choke. (choke should be about 1/4" open when set and cold - this is the choke take off, a fully closed choke plate will starve the engine of air and it will not start).
3. Crank engine - mine would usually fire right up, if it had been more than a week or so or it was cold, I might have to pump it once or twice more.

** If the fuel pump is installed correctly, it is wired to an oil pressure switch which will only allow the fuel pump to run when there is oil pressure. Simply turning the key to on should no run the fuel pump, you would need to crank it until it builds oil pressure (when the warning horn stops).

 

There is so many things wrong with the configuration in these pictures. First, the wiring is completely wrong. Second that is a lift pump and not a fuel pump for a carburetor. Third that is an automotive carburetor and not for marine use. And last but not least (that I can see) is the fuel line is not marine rated. These things are not incidental either. If you are unfamiliar a qualified marine technician should take all of this on. Not trying to be a butt wipe here but you have some significant safety hazards going on.
Carburetor fuel pressure should be around 6.5 PSIG.

 

It has braided line from somewhere to the carb. But definitely get the wiring rite , we used to set up our street car where the fuel pump only runs with oil pressure

 

If it is listed as a marine carburetor then my bad - sorry. Typically, at least on Holley carb's, there is a bowl drain tube so if the float gets stuck the fuel overflow runs down into the intake manifold and not over the top of the engine.
Visually, it looks like a typical lift pump which only puts out one or two PSIG.

 

The fuel lines need to be USCG approved Type A. SAE J1527 Type A. There is no way a steel braided hose is applicable.