These fuel pickups were originally developed for snowmobile applications, but they work great in rock-crawlers or in fuel tanks that don't have baffles. These are the same type of pick-ups that are in the Holley Universal In-Tank Mulit-Point Fuel Pick-up Kit [Holley part number 12-951 - two pickups per kit]. Walbro made those pickups for Holley.
The original Walbro pickups were the MP-10. Those were the pickups in the Holley kit, too. Those pickups had a 30 micron mesh. With fuel formula changes in recent years, the snowmobile manufacturers were noticing a type of goo building-up on the pickups. That goo was the new fuels reacting to the plastic fuel tanks. Walbro changed the mesh to 70 microns and there was no more buildup on the pickups. . The new part numbers are MP-12, MP-13, MP-14, MP-15, and MP-16.
How they work:
Have you ever sprayed water on a window screen? Recall that the screen will actually hold some of the water. These pickups work the same way. When the pickup is submerged in fuel, the fuel will pass through the mesh with ease. When fuel sloshes away from the pickup, the mesh will hold enough fuel to fill all the tiny holes. That mesh full of fuel acts like a solid. At this point, the pump, sucking on the pickup will cause the mesh to suck shut, preventing the pump from sucking air. When fuel covers the pickup once again, the valve will open up and transfer fuel.
These pick-ups have one or two 5/16 fittings. The pickups with two fittings can be used to connect pickups in series.
The inlet side of the pickup has a 70 micron mesh. The pickup is just under three inches in diameter and just under two inches tall. These pickups have been tested in gasoline to -40 F and in diesel fuel to 0 F. A single pickup can flow 40 gal per hour, so they work well with high-performance applications, too.
The Bleed Hole:
If your system has any posibiity of running completely dry, Walbro suggests that one pickup in the system should have a bleed hole. If your system doesn't have a bleed hole, it can become totally closed if all of the pickups close at once. If that happens, the closed pickups can take many minutes to re-open, depending upon how much vacuum the fuel pump has pulled. In extreme cases, you may have to open your fuel tank and remove a fuel line to break that vacuum.
The bleed hole is a very small hole in the disc that shuts-off the fuel flow. Runing a system with more than one bleed hole is not necessary or recommended. Since the bleed hole is a hole, a small amount of air will enter your fuel supply when that pickup is exposed. It is a necessary evil if there is a risk of running out of fuel. Place the pickup with the bleed hole in the position that will see fuel as long as possible. If your system will never run out of fuel, it is best to install pickups that do not have bleed holes.
The number of pickups you should install depends on the shape and orientation of your tank. You obviously need more than one pickup, because if you only have one, and it closes-up, you're done! Place the pickups in the extreme corners of your tank. That should give you access to the most fuel.
Since rubber hose rated for in-tank use is so expensive, many folks are using hard lines to the pickups. Pieces of copper tubing or brake line can be bent and run between connections. That reduces the need for in-tank hose to only a couple inches at each pickup or other connections. A hard line will also help keep the pickups in place and help weigh them down so the stay in the bottom of the tank.
If the fuel pickups are completely dry at startup, the pump will suck air. The pickups won't close unless they have been initially immersed in fuel [the mesh is wet].
|Part Number||Type||Bleed Hole||Price|
|MP-17||Flowthru-90||Yes||Not available in the aftermarket|
5/16 Hose 'Y'
Here's a 'Y' fitting you may need if you are going to put two or more pickups in your fuel tank - $4.
If you need hose that can survive immersed in fuel, check out this page.
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