Crownline with Volvo Penta TBI 350 motor

[Spiderhole]

Good morning,

I have a friend that we're trying to sort some stuff out on his boat. A few years ago the ECU went bad, and the previous owner decided to rip that and the TBI out. All the harnesses are still there. They stuck a carb on the boat. The boat now runs like absolute garbage. We want to put it back to it's original configuration. We are not exactly sure what we need to get, but being that this is not the nicest boat in the world, he's trying to be as cheap as possible. What is the technically correct TBI and ecu that we are looking for?

 

[Bondo]

Ayuh,.... If it runs like crap, there's something wrong,...

There's also no guaranty it'll run right with the Efi, after ya spend a few thousand bucks,...
Efi is not cheap, at All,...

What, Exactly is it doin', or not doin',..??

 

[bruceb58]

At this point I wouldn't go back to EFI. Hopefully, the guy switched the fuel pump so that it runs at the proper pressure with a carb and he changed things so that it only runs when the engine is cranking or the engine is running.

What model number is this drive/engine?

 

[Fishhead-1]

I see a fuel pressure regulator there, did they throw away the fuel cell and install a electric fuel pump?

 

[Spiderhole]

I see a fuel pressure regulator there, did they throw away the fuel cell and install a electric fuel pump?

I don't know the answer to this, but I will find out. It has never run right with the carb. The boat is a basket case, I have only taken a brief look at it, and he text me these pics yesterday. What would be a the correct fuel pump he would need? I am going to make the assumption whatever was on there for the fuel injection system is still on there.

Also, the boat doesn't go into reverse. The whole boat is super slow even when it's at WOT when it is moving forward.

 

[Scott Danforth]

the slow running and poor running are most likely tied together.

nothing wrong with a carb if it is properly set up. nothing wrong with using a high pressure pump and a regulator supplying the carb either

not going into reverse is another issue.

start with the basics, first, what is the compression reading numbers?

what is the quality of the fuel? have you tested the contents of the fuel/water filter?

 

[Spiderhole]

Assuming we need to put an electronic fuel pump on it for the carb, how do we do that? Obviously we'll need to install a new connector, but how and to where?

 

[bruceb58]

You already have an electric fuel pump. You can see it one of the pictures.

 

[Spiderhole]

You already have an electric fuel pump. You can see it one of the pictures.

Oh, my bad, I missed it. So it would or should be adequate for that carb?

 

[bruceb58]

Oh, my bad, I missed it. So it would or should be adequate for that carb?

The question is if the pressure regulator that is in there is really doing its job. The pump for an EFI system is much higher pressure than one for a carb system.

 

[Spiderhole]

The question is if the pressure regulator that is in there is really doing its job. The pump for an EFI system is much higher pressure than one for a carb system.

I doubt if it's adequately doing what it is supposed to do. I guess my question is can I convert it to an electronic fuel pump for a carb like what I have on my boat? According to him the thing floods which has made me wonder if maybe there's not also a problem with the carb floats or needles. I suppose if the best thing to do is keep the carb on there at this point I'd rather have the correct fuel pump than a pressure regulator.

 

[bruceb58]

Yep. For example, my Volvo has a carb and there is an electric fuel pump designed for it. You just have to buy a lower pressure fuel pump.

Next question for you...Often there are two fuel pumps. One is a lift pump and the other is a high pressure. You only need one. The lift pump may be the correct pressure. Can you take another picture of your existing fuel pump area to see what you have? Also, what is your model number and we can look up what it originally came with.

One more thing. On EFI, the ECU controls when the fuel pump is on. In your case, it's likely been eliminated. Does your fuel pump come on immediately when you turn the ignition switch to run without the engine actually running? If so, you will have to fix that as well.

 

[Spiderhole]

Yep. For example, my Volvo has a carb and there is an electric fuel pump designed for it. You just have to buy a lower pressure fuel pump.

Next question for you...Often there are two fuel pumps. One is a lift pump and the other is a high pressure. You only need one. The lift pump may be the correct pressure. Can you take another picture of your existing fuel pump area to see what you have? Also, what is your model number and we can look up what it originally came with.

One more thing. On EFI, the ECU controls when the fuel pump is on. In your case, it's likely been eliminated. Does your fuel pump come on immediately when you turn the ignition switch to run without the engine actually running? If so, you will have to fix that as well.

Thank you, this is very helpful. I'll try to check this weekend.

 

[Spiderhole]

Yep. For example, my Volvo has a carb and there is an electric fuel pump designed for it. You just have to buy a lower pressure fuel pump.

Next question for you...Often there are two fuel pumps. One is a lift pump and the other is a high pressure. You only need one. The lift pump may be the correct pressure. Can you take another picture of your existing fuel pump area to see what you have? Also, what is your model number and we can look up what it originally came with.

One more thing. On EFI, the ECU controls when the fuel pump is on. In your case, it's likely been eliminated. Does your fuel pump come on immediately when you turn the ignition switch to run without the engine actually running? If so, you will have to fix that as well.

It does have two pumps as you described. I think you're exactly right we can use that lift pump and just eliminate all the other stuff. The question we have is about your last paragraph, how do we hard wire this lift pump to function for a carburetor? We believe all of the original wiring for EFI is still in place

 

[bruceb58]

What is your model number and I can look up the spec for the lift pump.

As far as running the pump, here is the diagram for how the Volvo pump for a carb'd model would look like.

The signal labeled ignition switch goes to the start terminal. The terminal labeled alternator goes to the L2 terminal of the alternator. You have to put the diodes in there.

 

[Spiderhole]

No Title

What is your model number and I can look up the spec for the lift pump.

As far as running the pump, here is the diagram for how the Volvo pump for a carb'd model would look like.

The signal labeled ignition switch goes to the start terminal. The terminal labeled alternator goes to the L2 terminal of the alternator. You have to put the diodes in there.

Thank you, that is incredibly helpful. Only question... forgive my ignorance... what exactly are the diodes we would need?

I will get the the numbering off the pump today. Here are some pictures of what I think is the lift pump... I assume it is because it's the first pump the fuel goes through after it leaves the tank.

 

[Spiderhole]

The lift pump numbers show 3858261 & 218 01731A

 

[bruceb58]

That is the same part number used on carb'd models so it should work fine.

Any 5A or bigger diode would work. Physically bigger is better since less likely to break. Since its just going to the relay, there is hardly any current.

 

[Fishhead-1]

Bruce, where did they mount the original fuel cell on that engine? Doesn't look like there was enough room for it where that pump is at.

 

[Spiderhole]

What would happen if we left it with the wiring as it is right now?