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Fuel delivery

50onRED

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I’m trying to come up with a healthy fuel delivery system for my new motor. My old NA setup was an aeromotive a1000 T style pump that fed a mechanical pump then to the carb. Whelp now the engine has a blower and dual carbs. I’m looking at Aeromotive A2000 T (carburetor style) fuel pump with a return style regulator. My question is, do I even need a secondary mechanical fuel pump?
 

02HoWaRd26

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3.5L sump tank, seems like a rough one to beat imho.
 

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rivermobster

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Don't neglect the lines and especially the size fitting at the tank!!

If you have aluminum tanks, Imco has some trick inserts you can buy to hook the bigger lines too.

The fitting at the tank can be a huge restriction. Please don't ask me how I know...
 

monkeyswrench

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Don't neglect the lines and especially the size fitting at the tank!!

If you have aluminum tanks, Imco has some trick inserts you can buy to hook the bigger lines too.

The fitting at the tank can be a huge restriction. Please don't ask me how I know...
"...golf ball through a garden hose" comes to mind🤣

I learned that with cars. An SX pump through a factory pickup was "NFB", No F'n Bueno...live and learn;)
 

50onRED

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I would not run the mechanical pump at all. Block it off and remove that variable all together.
That was my thought. I’ve built tons of high horsepower fuel systems for race cars and I never used a traditional mechanical fuel pump, belt driven yes but mechanical no.
Why do so many boats have both?
 

50onRED

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3.5L sump tank, seems like a rough one to beat imho.
That’s an interesting concept. That also might be because your motor is fuel injected which needs a much larger fuel pressure as well as a fuel return. I’m also going to SS Hardline a lot of my system. The A2000 is good for 2000 HP so I know the pump will hang. I just can’t figure out why so many boats use an electric pump and a mechanical.
 
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50onRED

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Don't neglect the lines and especially the size fitting at the tank!!

If you have aluminum tanks, Imco has some trick inserts you can buy to hook the bigger lines too.

The fitting at the tank can be a huge restriction. Please don't ask me how I know...
That’s a great point. I’m pretty sure my tanks have 1/2 npt bungs so I should be able to use them. My Imco superfuel valve is good. I’m going to hard line the superfuel valve to the filter then to the pump then to a distribution block behind the motor to y off to the carbs. At least that’s my plan… and we all know how plans work out when building custom!
 

MK1MOD0

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That was my thought. I’ve built tons of high horsepower fuel systems for race cars and I never used a traditional mechanical fuel pump, belt driven yes but mechanical no.
Why do so many boats have both?
Redundancy. I lost an electric pump around 200 hrs. It went from 7psi to 5 psi, so I knew something was up. I was able to cruise back to the dock with no issues.
 

50onRED

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"...golf ball through a garden hose" comes to mind🤣

I learned that with cars. An SX pump through a factory pickup was "NFB", No F'n Bueno...live and learn;)
Yeah I’ll be feeding the pump with 3/4 SS then it will neck down at the carbs to -8
 

50onRED

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Redundancy. I lost an electric pump around 200 hrs. It went from 7psi to 5 psi, so I knew something was up. I was able to cruise back to the dock with no issues.
I thought about keeping my a1000 in the boat just in case since it’s still working fine
 

02HoWaRd26

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That was my thought. I’ve built tons of high horsepower fuel systems for race cars and I never used a traditional mechanical fuel pump, belt driven yes but mechanical no.
Why do so many boats have both?
My fuel system stock from Mercury Racing ran a mechanical pump, as does it still now with the twin electric pumps in the sump tank and EFI.
 

DarkHorseRacing

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With carbed setups that traditionally run a mechanical pump it takes some cranking to build fuel pressure. Adding an electrical pump allows the mechanical to prime immediately which means less cranking when fuel delivery is immediate.

EFI systems normally only run electrical because the mechanical can’t put out the pressure needed for injectors.
 

wet hull

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That’s an interesting concept. That also might be because your motor is fuel injected which needs a much larger fuel pressure as well as a fuel return. I’m also going to SS Hardline a lot of my system. The A2000 is good for 2000 HP so I know the pump will hang. I just can’t figure out why so many boats use an electric pump and a mechanical.
I would not use the A2000. I had multiple shit the bed. They dont just gradually start to die. Its sudden and unexpected. Went Weldon and its bad ass!!
Screenshot_20230326_195412_Chrome.jpg
 

DarkHorseRacing

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I heard Weldon are much louder than the Aeromotive pumps? I wanted at one point to replace my Aeromotive pump with a Weldon and I was advised I’d really hear it.

Is this true? Apparently the TCM 1200 switches from Aeromotive (found on the lower models) to Weldon and as we have that engine as well in a different boat I don’t recall really noticing any major difference between the two but it could come down to how it’s mounted and if it’s isolated.
 

Blackmagic94

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I’m trying to come up with a healthy fuel delivery system for my new motor. My old NA setup was an aeromotive a1000 T style pump that fed a mechanical pump then to the carb. Whelp now the engine has a blower and dual carbs. I’m looking at Aeromotive A2000 T (carburetor style) fuel pump with a return style regulator. My question is, do I even need a secondary mechanical fuel pump?
Fuelab or bust


Or you can do a fuel sump with walbro or Bosch pumps like I did on my jet boat.
 

Dalton

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That was my thought. I’ve built tons of high horsepower fuel systems for race cars and I never used a traditional mechanical fuel pump, belt driven yes but mechanical no.
Why do so many boats have both?

I think if a engine leans out from a bad fuel pump it can blow
 

wet hull

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I heard Weldon are much louder than the Aeromotive pumps? I wanted at one point to replace my Aeromotive pump with a Weldon and I was advised I’d really hear it.

Is this true? Apparently the TCM 1200 switches from Aeromotive (found on the lower models) to Weldon and as we have that engine as well in a different boat I don’t recall really noticing any major difference between the two but it could come down to how it’s mounted and if it’s isolated.
It is louder then the Aeromotive. Only notice when you cycle key on. When running I dont hear it.
 

MPHSystems

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That’s an interesting concept. That also might be because your motor is fuel injected which needs a much larger fuel pressure as well as a fuel return. I’m also going to SS Hardline a lot of my system. The A2000 is good for 2000 HP so I know the pump will hang. I just can’t figure out why so many boats use an electric pump and a mechanical.
Here’s the thing, you don’t want to use a 2,000 HP pump on a 800 hp engine. It heats the fuel and with most of the fuel being pumped back into the tank, it aerates the fuel. This will be more pronounced as the tank empties. Buy an appropriately sized pump for your engine.
 

50onRED

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Interesting. I’ve installed probably close to 60 Aeromotive pumps and have never had a single one go bad. Weldon makes a great pump as well. I also have my old A1000 for a backup just in case.
 

50onRED

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That’s what’s in my fuel sump is dual Bosch 088’s i believe, but definitely Bosch.
Bosh is probably the most reliable in tank pump that exists today so it makes sense that someone would use them for fuel injected applications. The issue I have is I need VOLUME not Pressure. I need to shove a garden hose of gas to my carbs and let the return dump the unused fuel back into the tank. The biggest mistake a carbureted blown engine builder can make is starving the blower of fuel. It’ll ruin the blower and make big boom in the block.
 

50onRED

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Here’s the thing, you don’t want to use a 2,000 HP pump on a 800 hp engine. It heats the fuel and with most of the fuel being pumped back into the tank, it aerates the fuel. This will be more pronounced as the tank empties. Buy an appropriately sized pump for your engine.
This engine is a 588 cu inch BBC with an 8.3l Whipple screw on top. It’s nowhere near 800 anymore. The engine is built to push well over 1500 but will be running low boost to keep it around the 1000 mark. I already have the A1000 in the boat now but it’s not going to be enough to feed 2 950 CFM carbs at full tilt. So that’s why I went to the A2000. Also because I am comfortable with Aeromotive since I’ve installed many Aeromotive pumps into hot rods and muscle cars during my automotive career.
 

AZLineman

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I've had the best luck with Malory 140s. With my PSI at full tilt never dropped pressure. #8 feeds and #10 to the distribution log then again #8 to carbs. Biggest pump in the world is limited unless you give it plenty of volume to pull and push through. Weldon, SX, Aeromotive all top notch. Innovation marine swore my the SX. I have a couple. Big heavy pumps.
 

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DaveH

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the biggest problem with nearly all fuel delievery systems in boats is not the size of the pump.

the real problem is a lack of consistent delivery of pure fuel, do to the piss poor design of the fuel tanks. keeping stable fuel pressure is critical on super charged engines.

hydro mats help, but the best way to take on the problem is a feeder pump (or pumps) to fill an accumulator that feeds to your main pump.

everyone just goes off the fuel pressure gauge but these gauges lie big time. air is compressible so what looks like stable fuel pressures on the gauge is really aeriated fuel getting to your engine. racey made a sight glass that connects inline with your fuel system and you would not believe what it revealed.
 

sintax

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the biggest problem with nearly all fuel delievery systems in boats is not the size of the pump.

the real problem is a lack of consistent delivery of pure fuel, do to the piss poor design of the fuel tanks. keeping stable fuel pressure is critical on super charged engines.

hydro mats help, but the best way to take on the problem is a feeder pump (or pumps) to fill an accumulator that feeds to your main pump.

everyone just goes off the fuel pressure gauge but these gauges lie big time. air is compressible so what looks like stable fuel pressures on the gauge is really aeriated fuel getting to your engine. racey made a sight glass that connects inline with your fuel system and you would not believe what it revealed.

Can you or @Racey elaborate on that?? I'd love to know more.

so theory being, run from fuel tanks, into intermediate tank (like a surge tank on a mfi setup?), and then into mechanical pump into regulator into carbs?

How big of an intermediate tank is recommended, for say... a 800-1000 hp?

could we just run a normal mfi surge?
 

DaveH

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Can you or @Racey elaborate on that?? I'd love to know more.

so theory being, run from fuel tanks, into intermediate tank (like a surge tank on a mfi setup?), and then into mechanical pump into regulator into carbs?

How big of an intermediate tank is recommended, for say... a 800-1000 hp?

could we just run a normal mfi surge?
the size of the surge tank isnt dictated as much by the HP of the engine, but instead by how bad your fuel starvation issue is because of the design of the tank or tanks.

many boats will run fine when the tank is full.....but the problem becomes much more pronounced as fuel level in the tank gets lower and lower. But even at full tank, the acceleration, deceleration and turning cause a "washing machine" effect that depending on the size and how the tank is made (no baffles), will result in very aeriated fuel even at full tank. once we cut a hole and put a clear lid on a tank it in a schiada so we could see inside the tank while running. it was staggering to say the least.

ideally you would want a lift pump as close to the outlet of the tank as possible. from there it plumbs to the surge tank (really a VST or vapor separator tank as Kinsler calls them) and the outlet of the VST feeds the main pump....electric or mechanical. the EFI return goes back to the VST and there is a return from the VST to the vessel main tank.

the larger the surge tank, the more your fuel system will tolerate pickup starvation and do a better job at separating the aeriated fuel and returning that to the main tank.
 

50onRED

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I've had the best luck with Malory 140s. With my PSI at full tilt never dropped pressure. #8 feeds and #10 to the distribution log then again #8 to carbs. Biggest pump in the world is limited unless you give it plenty of volume to pull and push through. Weldon, SX, Aeromotive all top notch. Innovation marine swore my the SX. I have a couple. Big heavy pumps.
What are the specs of your Engine? Ive had good luck with Malory pumps in the paast so that is def not off the table. From the looks of your thumbnail your setup is pretty similar to mine so im curious as to your build and the power it makes.
 

50onRED

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the biggest problem with nearly all fuel delievery systems in boats is not the size of the pump.

the real problem is a lack of consistent delivery of pure fuel, do to the piss poor design of the fuel tanks. keeping stable fuel pressure is critical on super charged engines.

hydro mats help, but the best way to take on the problem is a feeder pump (or pumps) to fill an accumulator that feeds to your main pump.

everyone just goes off the fuel pressure gauge but these gauges lie big time. air is compressible so what looks like stable fuel pressures on the gauge is really aeriated fuel getting to your engine. racey made a sight glass that connects inline with your fuel system and you would not believe what it revealed.
i imagine an acumulator tank would need some sort of return line to the tank to keep it from being pressurized. Im trying to get away from replacing my perfectly good imco superfuel valve but im not opposed to it if it will add reliability to my setup.
 

DaveH

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i imagine an acumulator tank would need some sort of return line to the tank to keep it from being pressurized. Im trying to get away from replacing my perfectly good imco superfuel valve but im not opposed to it if it will add reliability to my setup.
yes there is absolutely a return from the accumulator tank to the main tank. Kinsler recomends a 3psi check valve in this line. this puts 3psi in the bottle and 3psi to the inlet of the main pump.

the problem with the imco valve is generally it is the location. long lines to it where it is usually mounted on the transom, the another long line to the main pump. even worse is often times it is mounted ABOVE the level of the fuel tanks.
 

50onRED

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yes there is absolutely a return from the accumulator tank to the main tank. Kinsler recomends a 3psi check valve in this line. this puts 3psi in the bottle and 3psi to the inlet of the main pump.

the problem with the imco valve is generally it is the location. long lines to it where it is usually mounted on the transom, the another long line to the main pump. even worse is often times it is mounted ABOVE the level of the fuel tanks.
In my case my superfuel valve is about 20 inches from my starboard tank but the port tank is running through about 10 foot of line. The pump is located on the bulkhead between the motor and the back seat and is level with the bottom of both tanks. I’m seriously considering a sump tank now. My plan was to run 3/4ss hard line feed lines from both tanks to the superfuel valve and from there another 3/4ss hard line to the pump. Then from pump to a distribution block where it will split into -8 to both carbs. All of this will have fuel filters in line before and after the pump.
 

02HoWaRd26

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Hardliner’s in a boat vs a hotrod is a very different thing. One everything is solid mounted to a solid frame, the other is a big box of fiberglass that’s constantly flexing. Also fuel for a car will never be the same as a boat, how often does a car cruise with the throttle sitting at a constant 4,000 RPM’s and long bursts of 5200-6000RPM can’t do that on the road.
 

50onRED

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Hardliner’s in a boat vs a hotrod is a very different thing. One everything is solid mounted to a solid frame, the other is a big box of fiberglass that’s constantly flexing. Also fuel for a car will never be the same as a boat, how often does a car cruise with the throttle sitting at a constant 4,000 RPM’s and long bursts of 5200-6000RPM can’t do that on the road.
I understand your concern and have considered all of it. Proper fittings and cushion clamps and hoses where they need to be can decrease the chances of fittings coming loose and or line breaking. Even rigid car chassis have quite a lot of flex and race cars vibrate a ton. Most cars do not cruise at 4000 rpm but 2500 is very normal and performance cars see much higher rpm’s in bursts. Companies like Boeing and nasa use hard lines in many of their applications even where large amounts of flex are involved.

My minds not made up quite yet so the hardline isn’t a done deal yet. Im considering all information very seriously. That’s why I created this post in the first place. I respect your knowledge and always consider your input Peter and seriously appreciate you!
 

AZLineman

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What are the specs of your Engine? Ive had good luck with Malory pumps in the paast so that is def not off the table. From the looks of your thumbnail your setup is pretty similar to mine so im curious as to your build and the power it makes.
I always draw from both tanks, #8 feeds thru filter/pump, #10 to reg (#8 return, T to both tanks) #10 to dist log, #8 to carbs. 522/345 Dart Pro 1 heads, PSI 206B@70% or 14/[email protected]%, 1150's jetted 84/94, 4.5 PV's in front, .078 PVCR's, boost ref, chipoed @ 6400 right now. 1500+.
 

50onRED

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@02HoWaRd26
Whelp the SS line idea is shelved. I spoke to another rigger today and the issue isn’t the vibration and flex. It’s the fact that you can’t hand bend 3/4 SS. It has to be mandrel bent which is a major pain in the ass. So I’ll be sticking to my good ole braided hose!
 

50onRED

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I always draw from both tanks, #8 feeds thru filter/pump, #10 to reg (#8 return, T to both tanks) #10 to dist log, #8 to carbs. 522/345 Dart Pro 1 heads, PSI 206B@70% or 14/[email protected]%, 1150's jetted 84/94, 4.5 PV's in front, .078 PVCR's, boost ref, chipoed @ 6400 right now. 1500+.
That sounds like a beast! I love it. My build is very very similar. You’re definitely pushing more power than I will be.
Currently I have -10 line from both tanks to the superfuel valve then -10 to a filter&pump. Then -10 to a fuel log then -8 to the carb (my single carb NA Setup) now I’m thinking I’ll just keep the -10 and leave my fuel setup exactly how it is.

Do you have a return style regulator?
 

AZLineman

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That sounds like a beast! I love it. My build is very very similar. You’re definitely pushing more power than I will be.
Currently I have -10 line from both tanks to the superfuel valve then -10 to a filter&pump. Then -10 to a fuel log then -8 to the carb (my single carb NA Setup) now I’m thinking I’ll just keep the -10 and leave my fuel setup exactly how it is.

Do you have a return style regulator?
Mallory return style/boost ref. Cant use the reference with a screw blower, works ok with roots. Normally I just lock it 6.5 while idling/no vac connection.
 

DaveH

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Mallory return style/boost ref. Cant use the reference with a screw blower, works ok with roots. Normally I just lock it 6.5 while idling/no vac connection.
why would a certain type of supercharger not work with your regualtor?
 

50onRED

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Mallory return style/boost ref. Cant use the reference with a screw blower, works ok with roots. Normally I just lock it 6.5 while idling/no vac connection.
I was wondering the same thing. Why wouldn’t you be able to use the boost referenced regulator with a screw?
 

AZLineman

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PSI creates so much vacuum It sucks the fuel pressure down to 1 to 2 pounds at a certain low RPM cruise when set at 6ish at idle. It would even suck fuel through the pump when its off and stay idling. I even tried the infamous internal port elbow suggested by PSI for the signal and no diff. I tried off the intake T'd off my boost gauge too and no go. May just be a PSI thing. They were very aware of it. Not too many people run carbs on them anyways. 14/71, no prob. I just keep it 6.5 and its good. Works fine like that unlike my blow-thru Nova. It needs that boost ref fuel press
 

50onRED

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PSI creates so much vacuum It sucks the fuel pressure down to 1 to 2 pounds at a certain low RPM cruise when set at 6ish at idle. It would even suck fuel through the pump when its off and stay idling. I even tried the infamous internal port elbow suggested by PSI for the signal and no diff. I tried off the intake T'd off my boost gauge too and no go. May just be a PSI thing. They were very aware of it. Not too many people run carbs on them anyways. 14/71, no prob. I just keep it 6.5 and its good. Works fine like that unlike my blow-thru Nova. It needs that boost ref fuel press
I see, that’s so strange because logic would dictate that the manifold technically has almost no vacuum under the blower. And yeah the PSI is extremely efficient but I’ve never used one so that is new news to me. Definitely something to look into though.
 

AZLineman

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Makes no sense to me eithr and i swear im not crazy. Tried it more than once. Lol.
 

02HoWaRd26

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@02HoWaRd26
Whelp the SS line idea is shelved. I spoke to another rigger today and the issue isn’t the vibration and flex. It’s the fact that you can’t hand bend 3/4 SS. It has to be mandrel bent which is a major pain in the ass. So I’ll be sticking to my good ole braided hose!
So i don’t recall the exacts, i do believe stainless braid is ok, but the nylon braid and the real AN fittings aren’t USCG legal. Plan next season to go all to pushlock and USCG fuel line. Been told by two different shop the same thing. As when you look at say a TCM rig job it’s always pushlock.
 

50onRED

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So i don’t recall the exacts, i do believe stainless braid is ok, but the nylon braid and the real AN fittings aren’t USCG legal. Plan next season to go all to pushlock and USCG fuel line. Been told by two different shop the same thing. As when you look at say a TCM rig job it’s always pushlock.
I’m leaning that direction now for sure.
 
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