using an electrical fuel pump

[crm318]

im recently helping a buddy build a vortec headed 350 that doesnt accept mechanical fuel pumps. we bought a electrical fuel pump from mr. gasket and it says 12s on the side. we tried to start it today and it kept on clicking after it was already primed. then it looked like fuel was leaking out of the primary throttle shaft on the carb (quadrajet). what does the 12s mean. does this pump put out too much pressure? the engine didnt start anyways (initial start up and there a ton of things off im sure). what do yall think?

[rage'nrat638]

YEA.. you have to have a fuel pressure requlator in line set at 6-7 psi

[cooters]

i agree rat n rage, another way fuel comes out the shaft is if the float is set way to high, check pressure first though.

[BP68]

I ran into the same prob. Using a TBI 350 bottom end with Vortec heads. We used a Jeg's pump. Here is the link. The truck is still in the build process, but we fired the motor and ran it a couple minutes using this pump with no regulator and didn't seem to have any problems.

http://www.jegs.com/webapp/wcs/store...9850_-1_360609

[fastwillie 696969]

12 maybe 12 volts system most electric pumps go 4-7 lbs

[crm318]

so what does the 12s mean, 12 psi? do i need a pressure regulator(mr. gasket)?

[FLEET72]

Originally Posted by crm318

what does the 12s mean.

Model #.

Instruction sheet

The Mr. Gasket Micro Pump is self priming to 12 inches of lift, simple two bolt and two wire installation, built-in pressure relief, and has extremely low amp draw. (Average 2 amps at maximum delivery).

[crm318]

i followed all of these instructions. will a regulator have to be used?

[FLEET72]

Originally Posted by crm318

i followed all of these instructions. will a regulator have to be used?

If you are still unsure then put a pressure gauge on the pump outlet and measure it. If it 7psi or less, save your money. We use this type of pump on all of our gasoline powered generators (utility district) and most are at 5psi. The ticking you mentioned earlier is normal when power is applied to the pump, the built in pressure relief prevents excess pressure to be created. I would be more inclined to ensure carburetor adjustments are set correctly, i.e. float level, etc.

[crm318]

would this pump cause the carb to leak if there was too much pressure? the the carb was off of a perfectly running motor.

[johnnywagon]

Mr. Gasket #12s is a universal 12v volt pump that puts out 4-7 psi @ 35 gallons per hour. It shouldnt (?) over power a Q-Jet at all & technically you shouldnt need a regulator. Its very rare but if you wire them up backwards and mount them backwards they can pump some really high pressures??

[FLEET72]

Originally Posted by crm318

would this pump cause the carb to leak if there was too much pressure? the the carb was off of a perfectly running motor.

Not likely, could possibly be debris in the needle/seat assy. preventing complete fuel shut-off when the bowl is at the set level.

[FLEET72]

Well, I just found this opinion on the WeberCarbs.com site regarding fuel pumps; The Mr. Gasket pump is the same as a Facet pump.

Fuel Pumps and Fuel Pressure:
Fuel delivery is critical to the proper performance of any Weber carb. From a basic 32/36 DGEV to a set of Triple Sidedraft DCOE's. Webers rely on a stable full float bowl in order to mix the fuel and air correctly. Mechanical pumps very rarely do this. They pulse fuel instead of giving a smooth even delivery and the amount of fuel varies with engine RPM.

A Proper Electric Fuel pump will give the best performance and most stable tuning for any Weber carb application. We use only High Volme and Low Pressure pumps. Webers work best at approx 4 psi of fuel pressure (Not 2 psi like many of the older books stated.) and you need Volume not Pressure to keep the float bowl full.

We ONLY use the Carter Rotary pumps. They are High Volume (60-70 GPH) but only 4 psi. This is PERFECT for all Weber applications from a Single 32/36 DGV on a Truck, Jeep or Car to a Triple Sidedraft setup on a Road Race car making 300 HP...This pump DOES NOT and SHOULD NOT use a Pressure Regulator for any reason. That is why we use it....


Carter 4070 Fuel pump with Mounting Bracket kit

Problem Pump and Regulator setups:
These are combinations that many of you are using and you could be experiencing problems because of it.

Holly Fuel Pumps with Regulator:
This is a very common combination and it has alot of problems. The pump puts out too much pressure so you have to buy a regulator for it. The Regulator is just a restrictor that inhibits flow. This causes a huge loss of Volume and overloads the pump causing alot of noise and premature failure. This results in the float bowl going low or empty under hard acceleration and causes cornering problems.

Facet Fuel Pump:
This is one of those little square pumps with the transistor mounted on top that make a ticking noise all the time. These pumps are TERRIBLE. No volume and High Pressure. These pumps have been sold for many years with Weber and Mikuni conversions and have cause many people alot of tuning problems. They are a pulse type pump that delivers almost no volume (usually less than the stock mechanical pump did) and usually at High Pressure. This cause flooding at idle and lean out conditions under high load. Do not use them....