Fuel pressure

[hupiveneilija]

Hi,
Does anyone know how much pressure omc 3cyl carb/floatvalve can hold? Min. pressure as manual is 3psi when checking but what is max. they hold?

[filthy phill]

you dont need pressure so much, you need volume.
any pressure from about 2 to 5 is plenty of pressure for our type of carburettors, its just a good volume that is required.
the old style fuel pump for a omc triple will easy give enough fuel for a v4 140hp, and they do drink a lot of fuel.
if going to electric fuel pump you need one with pressure regulator and run it at around 4psi ,but you need a minimum of 20 gallons per hour of volume so its not working flat out all the time.
lots of people have the Holly 12 volt fuel pumps , the red top gives 71 gallons per hour at 7ps but should be fitted below fuel tank for good gravity feed to inlet !!!
the Holley blue top gives 88 gallons per hour at 9psi, again ideal to have fitted below fuel tank for good gravity feed !!!
Both these fuel pumps would need the regulator fitted to them to get pressure down to around 4 psi for outboards with carbs.
Lots of pretty cheap low pressure fuel pumps around, but are they as reliable as the omc old style fuel pumps due to needing 12 volt supply ( something else to go wrong).

[hupiveneilija]

These should cure the fuel problem. Facet redtop and regulator for that.
Wellcome big carbs here you have it! 😂😂

[filthy phill]

just make sure you dont get too much pressure, 4 to 5 psi is way plenty enough.

I am surprised your old normal fuel pump is not giving you enough. have you got the pulse conector on the block that has the blue colouring on it ? that is supposed to be more reliable. and I switched away from the vro fuel pump to the old style pump.
so much more reliable and easy to replace parts when needed..

the facet pump and regulator will pump plenty of juice for the motor, was it expensive ?
is the regulator a separate item ? or are you using the one built into the pump body ?
if yes then have it low as possible as that is about 6psi .

[filthy phill]

double post

[hupiveneilija]

just make sure you dont get too much pressure, 4 to 5 psi is way plenty enough.

I am surprised your old normal fuel pump is not giving you enough. have you got the pulse conector on the block that has the blue colouring on it ? that is supposed to be more reliable. and I switched away from the vro fuel pump to the old style pump.
so much more reliable and easy to replace parts when needed..

the facet pump and regulator will pump plenty of juice for the motor, was it expensive ?
is the regulator a separate item ? or are you using the one built into the pump body ?
if yes then have it low as possible as that is about 6psi .

Was little solid state, too little. Regulator have 1psi to 5psi range. Have to use that, pump makes 8psi. And this has best suction compared to other candidates.

What is expensive? 160e together yes, but less than repairing broken engine:D. We dont have anything cheap here, not even gas:p.

[filthy phill]

when i said cheap i was joking, i know how expensive these things are.
anything now in europe and uk is crazy prices.. today the fuel is £1.16 per litre = 1.30 euro's per litre. very expensive.

was you fuel pump on engine old type or vro type ?

[hupiveneilija]

There. Regulator after big filter so that dont affect to the pressure. Keeping that clear filter before pump allthough pump has one itself.2 filter before and 10micron big one after. Should be enough😬. 8psi &45gph with reg, i think my fuel supply is now good enough!

[filthy phill]

How much above bottom of tank is the pump inlet ? are these pumps ok for pulling up hill ?
What i mean is, are these pumps self priming . lifting ? most of the time on cars these are below the tank or level with bottom.

looks nice and neat where you have it installed

[hupiveneilija]

As i wrote earlyer, good suction 60cm vertical and self priming yes. Inlet about fuel toplevel.
Btw i think that sst60 pump is holley red and holley reg. That was another option but maker comment that it should mount below fuel level made me take facet.

[filthy phill]

Ahh it can suck fuel from 60cm down, thats pretty good, will definitely be plenty good enough for your engine.
I like the small disposable filter, they are good and cheap, plus see what is in there.
I have one of the large ones that has the solid canister and cant see anything at all. those clear ones I think are better and nice and cheap and available everywhere.

did you put regulator up near to the carburettor ?

[filthy phill]

I seem to be getting the internet a bit slow here, I ask a question then see its already been answered .