Mercury fuel pressure (carbed 2.4 200 hp)

[buelldave]

I have an 86 mercury 200 hp carbed fishing motor, all stock
I am ading a holly blue pump to the boat ( i need to regulate the pressure)
what should the fuel pressure be?
I am running 2 engines off of 1 pump after the regulator

[capnzee]

I would suggest no more than 7psi and no less than 3psi at all times. It would be nice if you could maintain 5psi at all times.

[MercNuts]

I have an 86 mercury 200 hp carbed fishing motor, all stock
I am ading a holly blue pump to the boat ( i need to regulate the pressure)
what should the fuel pressure be?
I am running 2 engines off of 1 pump after the regulator

WHY?

The stock fuel pumps are very reliable in good condition and easy to put kits in. A Holley pump which is rotor vein is prone to stopping dead with the smallest particle of grit meaning it needs a good filter between it and the tank. If you are out and the pump quits both engines have no fuel. As you are with two stock pumps you can always make it home if one pump fails which almost never happens. If you are planning on running the Holley through the stock pumps instead of removing them it is a bad idea. If you lose a diaphram you will pump raw fuel into the engine and if the Holley quits the stock pumps will not draw adequately through it. 7 PSI is too much pressure for Mercury needles and probably other brands too. I would never run over 5. Your primary concern is volume and not pressure. 1 PSI is adequate to run the motor if you have sufficient volume at 1PSI to keep the bowls full at full throttle conditions. The best thing to do on 1 stock 200's is put kits in the stock pumps and forget them.

[Jay Smith]

Some of my carbed as well as lazer EFI customers run the Holley RED regulated at the carb and or stock pulse pump at 3.5 to 4 lbs with no issues.

And "help" the stock pulse pump keep fuel to the VST tank needle and seat system and eliminate the pesky bulb...

Filters take the worry out of being close.....I would use a non intrusive screen type Raycor filter BEFORE the pump and a 33093 WIX after the pump. Should take care of any trash in the fuel issues..

My .02
Jay

[buelldave]

1st question answer (Why) the engines did not come with fuel pumps (dont know why) set screw in side of the blocks to block off the vacume hole, i guess the last people thaught that their little boat was a race boat, so I am working with what is there (

the way it is set up is fuel line leaves the tank into a marine machine fuel filterset up with a huge WIX filter ... 1/2 " line then to the pump 1/2" line to the regulator again 1/2" then into a large manafold spits into 2 1/2 lines (both sides go into the manifold 4 into 4) line then into 2 3/8 line to the engines 1 3/8 each

total of 4 engines 1 pump for 2 engines and 1 pump for the ther, each tank (each side) is set up the same, pretty slick set up, it was in the boat when I got it

so 5 lbs is the number that I need?

[perfmarine1]

so let me get this straight you are running 4 engines with 2 pumps, or 2 engines with 1 pump Hum I would not advise that.2 reasons 1-mercnuts is right, pump goes you are dead in the water. 2-when the pump gets week,and it will sooner or later,you risk detonating both motors at the same time,we call that double trouble. Now if you insist,Iwould run one pump for each motor, you would be safe if you installed fuel pressure gauges in the dash for each motor,hooked up as close to carb as possible.

[buelldave]

basicly 4 engines, 2 pumps, there are fuel pressure gages in nthe dash for each motor as well as manifold fuel pressure
like i said a real cool looking set up