Mosaic,
I just replaced and upgraded my entire
fuel system (hoses, filters, and
pump) a couple of months ago and installed a Walbro FRA-1. I have it wired to the ignition switch, so it runs all the time, and is still easy to use to bleed the system. The engine (3JH2E) lift
pump is strong enough to supply
fuel without the electric
pump but I figure it can't hurt to have the Wlabro assist the mechanical lift
pump. Besides, the Walbro pump has a life rating >5000 hours and should last as long as the engine.
As Cheoah pointed out it should be installed after the pump, otherwise your
fuel pump becomes the "primary"
fuel filter. You want to get dirty fuel to your filters where the crud can be handled. Anything that obstructs or catches the crud before it gets to your filters will stop the fuel flow (and engine), requiring a huge maintenance effort to find and clear. For this reason, I removed the fine mesh screen from the fuel tank pick up and increased the 5/16" ID hose size to 3/8" ID (luckily the pickup tube was already 3/8". Changing filters is easy, unclogging the fuel pickup or fuel hose is a nightmare even under the best conditions.