What is the best fuel pump steup?

[djtalon]

running a 2.4 bridgeport around 7500 rpm's, just curious what the best setup is? And what everyone is using
thanks
dave

[Paul]

Right now I have a weldon pump for my 2.4 BP EFI, I,am starting to have fuel pressure problems though and was told that a bosch pump would be better. Also how much life are you getting with engine at 7500 rpm?

[jerry]

http://www.simonmotorsports.com/page10.html . jerry know that the 2.4 charging systems suck. they put out 16 amps which will barely keep the battery charged , you hook up a weldon pump , it draws so much voltage you can lose pump pressure because the charging system can put out enough juice . check out the alt setup on simonmotor sport website. if you got the coin its killer !!!!

[djtalon]

what do i need besides the bosch pump, what is the part number? Do i need a regulator its a carb motor.
thanks

[patchesII]

you having carbs kinda changes things. i think they were assuming you have a fuel injection set-up. most guys run a holley fuel pump at around 3.5 to 4 lbs on a 2.4 carb setup. either the red or blue holley will be sufficient. other options would be mallory or barry grant. the other pumps like bosch and weldon are for fuel injection. when i ran 2.4 carbs i couldn't run more than about 3.5 lbs without having a bad stumble down low. it may have been because of weak needles and seats. good luck, erik kiser

[B.Mac]

Use all 3/8" fuel line from the pick up (tank) to a clear screen type pre-filter to the Holley Red pump mounted @ fuel level or just slightly above, to a water seperator, then up and out directly to the carbs bypassing the stock pump altogether. I ran mine right out of the box (7 lbs max pressure) with no problems works great.......
I'm runnin' a 2.5 carb motor up to 6500 but that pump will handle much higher RPMs.....it's designed to push not suck so keep it low and close to the tank.......oh yea...don't forget a lanyard kill switch for the fuel pump..........and no 90* fittings......

http://www.holley.com/HiOctn/ProdLine/Products/FMS/FMSFP/12-801-1.html

B.MAC:D

[Steven]

i had a warmed up 2.4 carb with a blue holley pump and the 16 amp system, never a problem with it. always had juice in the battery. :)

[Graham]

What kind of fuel pressure problem/s are you having with the Weldon pump?
It is quite possible your Weldon pump is a better unit than a Bosch.
Do you know what model number it is?

[Raceman]

I agree to with the Holley pump recomendation. Like B Mac said, a good filter BEFORE the pump is imperative because even the smallest piece of grit will lock it up tight.

One thing I do disagree on is the statement that they can be run unregulated. While it may have worked for some, it never has for me. Many (most) Mercury needles won't hold against 7 PSI and will be overwhelmed causing the carb bowls to flood over. Low pressure and plenty of volume is what makes a carb motor happy.

As far as the Weldons, they are excellent pumps, but seem to use more power than the Bosches. I know the earlier ones were prone to breaking shafts and Merc quit using them a long time ago. I don't know if the decision was because of failures or the price, which is considerably higher than the Bosche.

[johndezman]

two questions

1.) is this a "marine" pump - flash protected?

2.) how much affect do 90 deg fittings have on flow/pressure?

[Raceman]

One of the Holley's (either the Red or Blue) is Marine rated. I don't think in an carb outboard application that 90º fittings offer enough restriction to required flow to be significant.

[Paul]

Graham
The model no. for my weldon is 2001-A. The problem I have is with erratic fuel pump pressure 33 to 39 psi. I took the regulator to a fuel injection specialty shop and they told me it checked out ok. I also installed new fuel lines and checked all fittings, thats why I think it may be a bad pump but not 100% sure. Right now engine is at G-Force for rebuild so anymore trouble shooting will have to wait

[BLIZZARD]

i am always running bosch pumps in my 2.4 and 2.5 efi engines they always do fine
here in the netherlands you can buy them at the
car dumps cheap
i use the bosch pumps of big BMW cars
they never failed always good pressure
and a lot of fuel coming back too the tank

in my carb engine i did 6800 rpm with a stock pump on the engine without problems


carb engines don`t need fuel pressure
they need a lot of fuel at a low pressure
use a membrame pump not a roller pump
if you need too use an external pump
get an low pressure pump

Menno

[Techno]

I thinks it 10 feet. Could be wrong and it's much more but even at 10'
1 90 and 10' of fuel line is = to 20' of fuel line, about the length of your boat.
but if your running 1 90 chances are there are more like four so this could be anywhere from 10- 40' of line equivalant.
Thats why 90s are taboo. They introduce alot of friction. Whether it's too much who knows?
But get sloppy and carless put 90s on all the fittings and you end up having an incredibly long fuel line.
B.Mac how many 90s did you have in your system
:rolleyes:

If nothing else 90s shouldn't be put on the suction of an electric pump it puts in a vortexy thingy (technical term) in the wrong place.

[Raceman]

Techno, I agree with you theoretically, but with a carb outboard we're not even getting in the ballpark of the volume capacity that a Holley pump will support, so I don't think it's important. Unless I'm mistaken, both the Holley red and Holley blue are rated at 110 GPH at 7 PSI.

[B.Mac]

The Red puts out 71 GPH @ 4 PSI
More than any 2.5 that I know of will burn.......

My motor detonated because I was running a stock fishin' pump, supply line, water seperator, squeeze bulb and worst of all, a quick connect fitting @ 6300 RPM. I believe my pump was pulling bubbles and not enough fuel, leaned me out and she stuck:eek:

I canned all that fishin' stuff......straight shot now......no 90's just lottsa free flowin' 95 octane at @ 6lbs........
B.MAC:D

[Graham]

Your 2001-A Weldon pump will flow more fuel than a 984 Bosch unit.
It would be advisable to sort your problem out before your engine is operational.
The Weldons are reasonably easy to service, I would start at the easy end first, by checking your electrical connections, make sure you have a good earth & 12VDC supply.
Are you using a relay? If not, it would be worth considering installing one.
As you say the pressure is fluctuating it would be worth checking the relief in the pump body also.

I can send test figures on a 2001-A via email, if you provide an address.

[Paul]

Graham

E-Mail on the way.
Paul

[Techno]

Raceman
I'm just thinking of the extreme.
A 90 from the tank- it's already there to the W. seperator. It already has 2 90s drilled into it, add 2 more, for some stupid plumbing reason. Maybe it looks good.
Need 2 more for the pump. A bag of 90s was cheaper than getting some straights and some 90s??? I don't know.
Might as well add a couple here and there to get to the carbs in a nice looking fashion. Pretty soon that 7 lbs. aint 7 any more, and it isn't 7 anyway since it's the pumps rating not in a system.

Of course you do have a long way to go to get down below, what is it 4 lbs.? I think it's possible to do with 7 I added above plus several more. 70 feet is a long way to pump by itself what if it's a 100? I don't know what the output of the pump would be by then, don't forget you may have filters to overcome.

Not that 90s need to be feared, just not ignored.

If you saw my house you would understand. Some idiot used the joists as bending tools for the annealed copper he used. I also observed this persons intricate weaving abilities also. He had weaved 3 pipes for some reason.