Electric fuel pump on carb motor

MHorn0817

Active Member
May 16, 2021
205
Bowie, MD
Boat Info
1998 215 Express Cruiser
2011 260 Sundancer
Engines
5.7 Mercruiser Thunderbolt w/Alpha I
350 Mag MPI w/Bravo lll
We have a 1998 Sea Ray 215ec with 350 carb thunderbolt ignition. We are finally letting it go to a friend since we've gotten our 2011 260 Sundancer.

When we bought the 215, the previous owner installed an electronic fuel pump. I never found a good way to get the boat to fire right up. Sometimes it would, sometimes it would need to crank for 10 seconds, sometimes I'd need to crank and stop and crank again and it starts. It always starts, just not right away like I would like. I would like to try and figure this out before our friend takes it.

Before we bought the boat, the previous owner was always able to fire it right up. I asked his trick, a few times. He said he always just turns the key on for 10 seconds before starting it. I've done 0, 5, 10, 15 seconds and nothing recreates a immediate fire up.

Does anybody have any ideas what it could be? I've read electric fuel pump set up can be funny on a carb motor. Should I have to pump the throttle or no? Does the choke still need to be hooked up? Could it be some other underlying issue?

Any help and/or ideas would be much appreciated. Thank you in advance.
 
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.

attachment.php
 
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.
 
Thank you for the replies and help. It'll be a couple weeks until I get to the boat so I'll have to wait until then to check out what you guys suggested because I do not remember off hand.
 
Fuel pump runs with the key on. It is wired to the coil and battery ground.

The choke was closed 3/4 of the way. Didn't change or move when pumping the throttle.

I did not start or attempt to start because the boat is still winterized.
 
Fuel pump runs with the key on. It is wired to the coil and battery ground.

The choke was closed 3/4 of the way. Didn't change or move when pumping the throttle.

I did not start or attempt to start because the boat is still winterized.
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.
 
Okay, so the choke should be fully closed? I've read different posts about being all the way closed and mostly closed, so not sure which is correct.

The fuel pump was powered on and clicking but no fuel was coming out. I had the key on and looked down the carb and it was dry. I guess next month when I'm ready to unwinterize, I'll which it while someone cranks the key.
 
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).
 
It's definitely not wired correctly after looking at it. The boat always starts, just never the same way. Although it does seem like cranking a bit is always a must.
 
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 I Google the carburetor information, it comes up as Edelbrock 600cfm Marine carburetor. What makes it not a marine carburetor?

There's no identification on the fuel pump/lift pump. What makes you say it's a lift pump and not a fuel pump?
 
Braided line goes from the fuel/water separator to the carburetor.
 
And marine hose fuel line from the pump to the fuel/water separator.
 
If I Google the carburetor information, it comes up as Edelbrock 600cfm Marine carburetor. What makes it not a marine carburetor?

There's no identification on the fuel pump/lift pump. What makes you say it's a lift pump and not a fuel pump?
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.
 
I was able to find and confirm the pump is a seachoice cube electric fuel pump, part number 20351.
 
PXL_20230219_170829572.jpg
 

Forum statistics

Threads
113,118
Messages
1,426,521
Members
61,035
Latest member
Lukerney
Back
Top