Guys,
If the pump is just for bleeding consider these points.
#1 If the pump is not located so as it is a "by-pass" path, used only for bleeding, then it must be capable of allowing fuel to flow through it when it is not energized. Not all pumps are rated for this and pumps that are not can put undue strain on the diaphragm of the main fuel pump.
#2 Placing a pump on the tank side of a Racor can lead to spilled diesel. I have seen this all to often when an owner installs the gasket with a twist, very easy & common to do. Once you pressurize the pump and move yourself to the engines bleed screw, you often don't notice that fuel is spilling out of the Racor due to a poorly seated "square" o-ring. I have had this happen to a fair number of customers. By placing the bleed pump on the engine side of the Racor you are pulling a vacuum and won't force an over fill & spill. Once you run the engine the twisted gasket will quickly become apparent but you won't loose much fuel unless the Racor is installed below the fuel tank where it creates a siphon. By placing it in the tank side of the Racor you also risk over-pressurizing an installed vacuum gauge.
#3 If the pump is not set up on its own bypass loop raw unfiltered fuel will pass through it continuously and the very small surface area internal screen will clog thus rendering your entire fuel system plugged and inoperable.
#4 The pump, its seals, and design must be diesel capable. Many of the small cheapies are gasoline rated only.
#5 If the engine has a diaphragm type cam driven pump (most Yanmars) you are better to suck on the outlet side of that pump in order to not risk "blowing" the diaphragm by over-pressurizing it. They deal much better under vacuum than pressure.. This also serves to keep the down stream part of the system under vacuum, which helps to prevent pressure leaks into the bilge.
Also consider that I winterize and service about 30 Yanmar's each season and the on engine thumb bleeder is quick and easy, if you've pre-filled both filters at change out (the best practice when applicable). I use an MSR mountain climbing camp stove fuel bottle as my filter filler. Rugged, excellent seal and it's never leaked on me once even when crammed into a tool bag.
Course if you own a Mitsubishi based Westerbeke you just hot wire the fuel pump, off the glow solenoid, with an alligator jumper, and it self bleeds, even empty filters, in a few seconds. You can also hot wire the Universal pumps too. I have a test lead with a momentary switch in it for just this purpose. With the Yanmar you just have to bend over and press the thumb lever..
