Switching from Volvo TBI to Carb on a 1996 5.7 GI

camboat

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Great work and congrats!
Question:
did you use the bypass or blocking fuel regulator?
I didn’t use a bypass or blocking regulator. I’m using a Holley 12-803 set to 5lbs. Is this ok.
 

camboat

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Thanks
I haven’t touch the timing yet. Both the TBI and carb are set to 8 deg TDC. I will sea trail it and see what it does under a load.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Thanks
I haven’t touch the timing yet. Both the TBI and carb are set to 8 deg TDC. I will sea trail it and see what it does under a load.
You can run 10 - 12 BTDC with good fuel
 

camboat

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Ran the engine in the driveway to check everything out before taking the boat out for a sea trial. After running for ten minutes I could smell I very faint gas odor. I shut everything off. The fuel pump is barely leaking (red arrow) where the motor canister is pressed on the inlet housing. I called Carter. Not much help. I will return it a try one more Carter pump 🤞🏻. Not sure I trust the Carter fuel pump. Maybe that’s why it’s so noisy. All of the fitting are dry.
 

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alldodge

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What's the blue sealer on the threads?
If that's silicone, don't use that
 

camboat

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Permatex gas proof sealer
Is this the wrong stuff for thread sealer? The threads are not leaking
It’s the pump.

If there is something better, please let me know.

Thanks
 
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camboat

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Is there a better electric fuel pump than the Carter? I don’t like it that a brand new pump is leaking in my engine compartment. I have a replacement Carter pump coming. I may send it back and find a better pump.
 

alldodge

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Permatex Aviation Sealer

Carter makes a good pump and if the pump and I'm skeptical it's actually leaking there. I would think it's leaking at the fitting

The part that screws into the pump is NPT right?
 

Lou C

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Looking at the edge of the outlet, is that casting flash or a crack? I think casting flash. I think those threaded ports on the pump are usually NPT but on the three carbs (Q-jet, Holley & Edelbrock) I have for the fuel inlets they use straight threads and a double flare fuel line fitting. Might be a good idea to go back & check, I have a set of regular thread chasers and ones for NPT threads.
 

camboat

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The outlets are outside of the area that is getting fuel in. The fittings aren’t leaking I double checked with a paper towel while the engine was idling. I pulled it and returned it. It was also really noisy. I had it mounted on 3/4” rubber spacers. I’m not taking any chance for a fuel leak. I ordered a Walbro FRB-13-2.

Thanks
 

camboat

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Installed the new Walbro FRB 13-2 fuel pump today.(nice pump) Ended up resealing all the fitting threads with Gasoila thread seal. The pump was noisy getting it primed. Once prime, it was really quite compared to the Carter.( I think I got a bad Carter pump). Ran the new setup for a 1/2 hour in the driveway. No leaks, the fuel pressure was a steady 5lbs. Everything thing is working good. I will sea trial the boat next week.

Thanks again for everyone’s help!
 

camboat

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I have another question
I wired the purple/white wire to the top left post per wiring diagram. Checking voltage. This post only puts out 7 volts to the choke. Holly And Rochester carbs only need 7 volts for the electric choke. The edelbrock 1409 needs 12-14 volts. Can I add the purple/white wire to the solid purple wire that is on lower left post. It puts out 12 volts and runs to the ignition, coil, alarm buzzer, and solenoid. Per the wiring diagram I don’t see any inline diodes that would interfere with it.

On a sea trail I gained 300 rpm over the old setup at wot. I discovered that I could probably get another 200-300 rpm getting the throttle linkage adjusted when I got home looking at things. Still fine tuning things.
1770336501622.png
 

Scott06

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I have another question
I wired the purple/white wire to the top left post per wiring diagram. Checking voltage. This post only puts out 7 volts to the choke. Holly And Rochester carbs only need 7 volts for the electric choke. The edelbrock 1409 needs 12-14 volts. Can I add the purple/white wire to the solid purple wire that is on lower left post. It puts out 12 volts and runs to the ignition, coil, alarm buzzer, and solenoid. Per the wiring diagram I don’t see any inline diodes that would interfere with it.

On a sea trail I gained 300 rpm over the old setup at wot. I discovered that I could probably get another 200-300 rpm getting the throttle linkage adjusted when I got home looking at things. Still fine tuning things.
View attachment 414566
That’s where mercruiser takes the 12 v from the purple 1409 will also need a ground wire for choke , I just attached mine to carb body
 

camboat

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Thanks Scott
That’s what I was thinking. I added a 7 amp inline fuse and moved it to the ignition purple wire. I will check it out in the morning and see if the choke works better.

Thanks again. Cheers!
 

camboat

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Just a quick update. I got everything dialed in today. The choke is working good now that it’s getting 12 volts. It’s running so much better than before. Converting from TBI to the edelbrock 1409 is the best thing I could have done for this engine. No more chasing gremlins from the old discontinued wiring harness. I can do most of the work myself now. I would do this conversion again in a heartbeat. Now I just have to wait for boating season.

Thanks again for everyone’s help!
 

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Lou C

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Excellent job I have a brand new 1409 I might put on my 4.3 if the Quadrajet acts up…
 

camboat

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It’s been a fun project. The 1409 was easy to get it dialed in. Now on to redoing the dash and flush mounting the chart plotter and depth sounder.

Thanks again 🍻
 
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