Fuel Delivery Question....

[n2otoofast4u]

Ok, so I own this killer jet bote and its been damn flawless until it wasn't, but that's another story. I only had 1 issue with the boat and its fuel delivery.

After I make 4 or 5 good passes the level of fuel in the tank becomes low enough that when I lift hard the fuel sloshes to the front and starves the pump (High pressure EFI pump) and 60% of the time it wont re-prime. Typically not an issue, because I make 3-4 passes, go to the beach, flip a valve, transfer fuel to the other tank to fill it, and I'm off for another 4-5 passes. It NEVER runs out of fuel under load, because all the fuel is in the back. The issue as I see it is that the tanks are below the level of the pump, but I don't have a choice for that. The question is how to re-prime the existing pump when it runs out? Tap a fitting just before pump inlet and use a little auxiliary pump to flood it? I'm open to REASONABLE suggestions and have included a VERY well put together drawing of the conditions although its not 100% accurate, it represents the problem.

 

[DarkHorseRacing]

Sounds like you need baffled tanks.

The problem with adding some aux pump is if you put it in the front of the tank to get the fuel that sloshes forward it’s sucking air when you make a pass and the gas is at the back of the tank. You’d need some kind of fuel sensor to turn it on and then off when it can’t sense it (kinda like a ditch witch but obviously not that in the tank).

The other thing I could think of would be to run a mechanical fuel pump before the electric pump in such a way that it only primes the pump and all other times it just returns fuel to the tank. Like some kind of check valve?

 

[90 Laveycraft]

Luv the Burd!!

 

[n2otoofast4u]

Sounds like you need baffled tanks.

The problem with adding some aux pump is if you put it in the front of the tank to get the fuel that sloshes forward it’s sucking air when you make a pass and the gas is at the back of the tank. You’d need some kind of fuel sensor to turn it on and then off when it can’t sense it (kinda like a ditch witch but obviously not that in the tank).

The other thing I could think of would be to run a mechanical fuel pump before the electric pump in such a way that it only primes the pump and all other times it just returns fuel to the tank. Like some kind of check valve?

If I could run a mechanical pump Id use a GOOD one to feed a surge tank and be done, but the cam is billet roller and as I understand it that's a no-no, or at least frowned upon. I could run a 6qt surge tank, use a Holley billet mechanical pump to feed it ,t return to the saddle tanks, and run my high pressure pump supply/return from/to the surge tank. Ideally this is the move, but again I haven't gotten warm fuzzys about doing that.... yet.


EDIT.. As I type that, I am not sure if my new block even has a fuel pump location on it..... I'll call tomorrow.

 

[Boat 405]

A surge tank for EFI is what most guys do. Big tanks feed into a small 2.5 gallon tank that is always full. I've seen it done many ways even a holley fuel bowl float setup on the side of a tank. Thats just one way I've seen it done. But none the less. A surge tank would help you.

 

[monkeyswrench]

Could you run a high volume/ low pressure pump to a surge tank with and run a orifice or valve to keep the surge under low pressure?

 

[monkeyswrench]

A surge tank for EFI is what most guys do. Big tanks feed into a small 2.5 gallon tank that is always full. I've seen it done many ways even a holley fuel bowl float setup on the side of a tank. Thats just one way I've seen it done. But none the less. A surge tank would help you.

I've done the Holley float bowl on a small moon tank on an old Hilborn setup...made it nice to not carry a squirter in a cup holder

 

[ChrisV]

Surge tank.

Small pump in the main tank thag feeds the surge tank. The. A mechanical pump from surge to engine. You’ll have all the fuel…

 

[n2otoofast4u]

A surge tank for EFI is what most guys do. Big tanks feed into a small 2.5 gallon tank that is always full. I've seen it done many ways even a holley fuel bowl float setup on the side of a tank. Thats just one way I've seen it done. But none the less. A surge tank would help you.

I agree a surge tank is the best option, it’s just not an easy or aesthetically pleasing option at least to this point that I have dreamed up.

 

[Nanu/Nanu]

Man you need more street cred bra! Clearly according to your artistic rendering of the problem stated above youre having to make to many passes to prove "Gator dont take no Shit!"


My only non invasive solution would be weight. Ive only read about people adding weight to the front end. Is that an option for you?

 

[FlatNv]

Have room to add a sump to tank? I use a small elect fuel pump to prime my mechanical pump. It pulls from fuel line @ bottom of tank and goes into barrel valve with one-way nozel. ( From alkydigger) Not familiar with your setup if that's an option?.. like the detailed drawing

 

[Bigbore500r]

Is it possible to access the fuel pickup in the tank? If so - Holley Hydramat might do the trick.

HydraMat - Holley Performance Products

The amazing HydraMat is a patent-pending fuel reservoir system designed to reduce fuel starvation issues present in hard cornering, acceleration, stopping, inclines, and low fuel conditions.

www.holley.com

 

[Clank123]

Fuel pumps are just that..,pumps.
None of them are great at drawing fuel.
I’ve done a fair number of boats using a weir or sump tank, usually when using an injector pump and saddle tanks.
In your case, not as familiar with EFI set ups and the pressure needed but for me a quick fix to try would be, given your drawing, to move the pump further up the transom and rotate it so you can run the inlet in the bottom of the pump and the out line from the top. All that looping of the hoses that you currently have is not a great idea. Never seen a pump mounted, in my mind, upside down. I’d even try to mount it horizontally if possible.
Also not a bad idea to put a lightly sprung one way valve at the tank outlet.
Also, try not to chop the throttle as much unless it’s for safety.
Those tunnels are like driving a floating lazy boy compared to a flatbottom.

 

[DaveH]

if you have starvation bad enough to loose prime, i have news for you, you have fuel aeration and instability even under acceleration. you just arent seeing it with a cheesy gauge.

 

[n2otoofast4u]

if you have starvation bad enough to loose prime, i have news for you, you have fuel aeration and instability even under acceleration. you just arent seeing it with a cheesy gauge.

I can see the entire run on the data log, on my laptop, literally every second of it! It doesn't loose a drop of fuel pressure until about 2.3 (or longer) seconds after the TPS is back at 0%. Even then it will hunt from 45-20 ish PSI, and at times pick it back up, but at times (and I think its when I am driving into not perfectly flat water) it won't pick it back up. So no, I do not have fuel instability under acceleration, and if the tank is 100% full, I don't lose fuel prime at all, and the pressure NEVER falters!

FYI, the only gauge in the entire boat is on the CO2 bottle.... I'll double check to see if its "cheesy" or not.

 

[QC22]

Sounds like you need baffled tanks.

Doesn't seem like you've considered this option much. If you aren't aerating as you note, a baffle(s) would keep the fuel aft longer for your deceleration scenario. You'd have to remove the tank(s) for mods of course. Probably just the starboard tank based on your drawing. I don't see a line from the port tank, but it must be there to refill the starboard (main) tank as you described in 1st post.

 

[Todd Mohr]

I had the same problem with a flatty, I ended up switching to a T tank and that solved it. I kept 1 side tank and used a extra fuel pump to refill the T tank, it was only 6 gallons.

 

[monkeyswrench]

I can see the entire run on the data log, on my laptop, literally every second of it! It doesn't loose a drop of fuel pressure until about 2.3 (or longer) seconds after the TPS is back at 0%. Even then it will hunt from 45-20 ish PSI, and at times pick it back up, but at times (and I think its when I am driving into not perfectly flat water) it won't pick it back up. So no, I do not have fuel instability under acceleration, and if the tank is 100% full, I don't lose fuel prime at all, and the pressure NEVER falters!

FYI, the only gauge in the entire boat is on the CO2 bottle.... I'll double check to see if its "cheesy" or not.

Question that may or may not be relevant. What is your fuel pressure regulator set up like? Is it a boost sensitive deal, or is that all handled by the computer stuff? Just curious if for any reason you could have fuel, but not adequate flow or pressure. Doesn't sound like it though, but I always look for weird possibilities...they're the evil ones that suck the life out of you

 

[Racey]

Ok, so I own this killer jet bote and its been damn flawless until it wasn't, but that's another story. I only had 1 issue with the boat and its fuel delivery.

After I make 4 or 5 good passes the level of fuel in the tank becomes low enough that when I lift hard the fuel sloshes to the front and starves the pump (High pressure EFI pump) and 60% of the time it wont re-prime. Typically not an issue, because I make 3-4 passes, go to the beach, flip a valve, transfer fuel to the other tank to fill it, and I'm off for another 4-5 passes. It NEVER runs out of fuel under load, because all the fuel is in the back. The issue as I see it is that the tanks are below the level of the pump, but I don't have a choice for that. The question is how to re-prime the existing pump when it runs out? Tap a fitting just before pump inlet and use a little auxiliary pump to flood it? I'm open to REASONABLE suggestions and have included a VERY well put together drawing of the conditions although its not 100% accurate, it represents the problem.

View attachment 1338001

You need a swirl pot, vapor separation tank, that is fed by a lift pump. You then draw fuel for your main pump from this small tank.

I can't tell you how many times i have dealt with this problem, and how many motors i have seen go lean and pop because nobody wanted to listen up front.

A lift pump and vapor separation tank will solve your issue 100% of the time.

The other thing that you may not be noticing is that even when you are running you are most likely running lean continually from cylinder to cylinder as fuel vapor is mixed with liquid fuel and being delivered out your injector. Accelleration is not just forward motion, you are also dealing with up and down jarring from the motion. You will see these issues manifest on an O2 reading, you will keep retuning areas of a map that previously were fine and now are lean, or you over tune and then under smooth conditions they are now fat.

Most times you will never seen a hint of it on a fuel pressure gauge. Not at all. Not even 1psi of fluctuation.

With a proper setup you can empty your main tanks to a cup of fuel or less and still be running perfectly safe until you are totally out of gas. (At which point there is nothing that can save you regardless)


Tank baffles WILL NOT FIX THIS. If you saw how bad the fuel aerates and foams it would blow your mind.

I had to build a high pressure glass tube to prove the naysayers what i was telling them was true. It can be plumbed directly inline with your fuel rails so that you can visually watch the vapor pass through the system.

Me and DaveH have been fixing these problems for at least 15 years now across a wide variety of vehicles from boats to off-road race cars.

A properly built vapor separation tank can be less than a quart and feed well over 1,500hp no problem. They do not need to be big if they are designed properly.

 

[ChrisV]

I agree a surge tank is the best option, it’s just not an easy or aesthetically pleasing option at least to this point that I have dreamed up.

treat it like a race car. Fill up every pass.

 

[rivermobster]

Fuel pumps are just that..,pumps.
None of them are great at drawing fuel.
I’ve done a fair number of boats using a weir or sump tank, usually when using an injector pump and saddle tanks.
In your case, not as familiar with EFI set ups and the pressure needed but for me a quick fix to try would be, given your drawing, to move the pump further up the transom and rotate it so you can run the inlet in the bottom of the pump and the out line from the top. All that looping of the hoses that you currently have is not a great idea. Never seen a pump mounted, in my mind, upside down. I’d even try to mount it horizontally if possible.
Also not a bad idea to put a lightly sprung one way valve at the tank outlet.
Also, try not to chop the throttle as much unless it’s for safety.
Those tunnels are like driving a floating lazy boy compared to a flatbottom.

What he said. ^^^

Electric pumps don't Draw fuel, so having them above the fuel level is normally a BAD idea.

On my BIL's ocean boat, I didn't have a choice either. I did find some electric pumps designed to draw, but they were over 300.00 each, and were designed for carbs (low pressure).

Same as everyone else has mentioned, you need a small surge tank, with an internal EFI pump and a low pressure pump feeding it.

Maybe @cyclone has a recommendation for what would be the best one?

 

[HighVoltage329]

I was having the same issues when my tanks got low. Surge tank solved it.

 

[lbhsbz]

There are plenty of fuel pumps that draw fuel…they just say Carter on ‘em and aren’t machined out billet and anodized 3 different colors.

Regardless, you need a surge tank…doesn’t have to be intrusive or big or ugly. A piece of foot long 4” round aluminum tube with a ends welded on will work fine…stand it up somewhere…put the pickup on the bottom and the supply and return on the top.

 

[DaveH]

I can see the entire run on the data log, on my laptop, literally every second of it! It doesn't loose a drop of fuel pressure until about 2.3 (or longer) seconds after the TPS is back at 0%. Even then it will hunt from 45-20 ish PSI, and at times pick it back up, but at times (and I think its when I am driving into not perfectly flat water) it won't pick it back up. So no, I do not have fuel instability under acceleration, and if the tank is 100% full, I don't lose fuel prime at all, and the pressure NEVER falters!

FYI, the only gauge in the entire boat is on the CO2 bottle.... I'll double check to see if its "cheesy" or not.

fuel vapor is compressible. thats why your transducer doesnt pick it up.

 

[gottaminute?]

Ok, so I own this killer jet bote and its been damn flawless until it wasn't, but that's another story. I only had 1 issue with the boat and its fuel delivery.

After I make 4 or 5 good passes the level of fuel in the tank becomes low enough that when I lift hard the fuel sloshes to the front and starves the pump (High pressure EFI pump) and 60% of the time it wont re-prime. Typically not an issue, because I make 3-4 passes, go to the beach, flip a valve, transfer fuel to the other tank to fill it, and I'm off for another 4-5 passes. It NEVER runs out of fuel under load, because all the fuel is in the back. The issue as I see it is that the tanks are below the level of the pump, but I don't have a choice for that. The question is how to re-prime the existing pump when it runs out? Tap a fitting just before pump inlet and use a little auxiliary pump to flood it? I'm open to REASONABLE suggestions and have included a VERY well put together drawing of the conditions although its not 100% accurate, it represents the problem.

View attachment 1338001

our surge tank is fed by t

he mechanical pump. vents out top. overflows to both side tanks. accepts the return fuel. and feeds the hi pressure pump. we ran the same on the efi turbo motor .

 

[n2otoofast4u]

$2k later here’s the end result.

I used a dry sump oil tank, and a cam driven mechanical pump to feed the tank. High pressure pump pulls and returns to tank. Overflows feed back into saddle tanks.

I hope the next owner appreciates the cubic fkn dollars I’ve spent on this thing!!

I need a Parker pal to help me a week from Friday! Nothing like a maiden voyage 1200 miles from home!

 

[ChrisV]

View attachment 1344017 View attachment 1344018 $2k later here’s the end result.

I used a dry sump oil tank, and a cam driven mechanical pump to feed the tank. High pressure pump pulls and returns to tank. Overflows feed back into saddle tanks.

I hope the next owner appreciates the cubic fkn dollars I’ve spent on this thing!!

I need a Parker pal to help me a week from Friday! Nothing like a maiden voyage 1200 miles from home! View attachment 1344019

That’s badass! You going to Parker the 15th?

 

[Riverbottom]

View attachment 1344017 View attachment 1344018 $2k later here’s the end result.

I used a dry sump oil tank, and a cam driven mechanical pump to feed the tank. High pressure pump pulls and returns to tank. Overflows feed back into saddle tanks.

I hope the next owner appreciates the cubic fkn dollars I’ve spent on this thing!!

I need a Parker pal to help me a week from Friday! Nothing like a maiden voyage 1200 miles from home! View attachment 1344019

Let me know, I should be home on Friday if you need help.

 

[HighVoltage329]

That's a great fuel set up. Even if the mechanical pump can't keep up with that beast at WOT you have enough volume in the surge tank that it will never be an issue.

 

[n2otoofast4u]

That's a great fuel set up. Even if the mechanical pump can't keep up with that beast at WOT you have enough volume in the surge tank that it will never be an issue.

That is my thoughts exactly. The mechanical is supposed to pump 170gal hour. It will keep up everywhere other than WOT, and with about 2gal usable in the tank, there should never be an issue as the longest I have stayed WOT was just over 10 seconds. The driver and the boat run out of talent much longer than that!

 

[rivermobster]

View attachment 1344017 View attachment 1344018 $2k later here’s the end result.

I used a dry sump oil tank, and a cam driven mechanical pump to feed the tank. High pressure pump pulls and returns to tank. Overflows feed back into saddle tanks.

I hope the next owner appreciates the cubic fkn dollars I’ve spent on this thing!!

I need a Parker pal to help me a week from Friday! Nothing like a maiden voyage 1200 miles from home! View attachment 1344019

I know Berry has been super busy lately, but maybe he will be around?

@obnoxious001

 

[gqchris]

Thats badass! Came out great also brother!

 

[poncho]

When I saw the boat for sale I wanted to pull the trigger so bad but I knew I wouldn't do that level of boat justice, you have.
I had just sold my TX-20, too slow and wanted a quicker boat for me and the kids.

 

[obnoxious001]

I know Berry has been super busy lately, but maybe he will be around?

@obnoxious001

Might be able to get Riverbottom and test here from my ramp, but I need to check what time my other appointment is that day.

 

[n2otoofast4u]

Might be able to get Riverbottom and test here from my ramp, but I need to check what time my other appointment is that day.

I didn't realize you had your own ramp, that would be ideal.

I have never boated Parker, and this is (2) fold. (1) I want to say I ran the boat on the Parker strip, and (2) shakedown, look, test, scratch head, etc. Ideally I could leave the trailer in the water, make some short pulls, slide back on the trailer, double check, make a few more pulls and back on trailer, etc. I will PM you Barry.