What is the logic behind that? I don?t understand why so many folks circumvent the electric fuel pump. Van?s has stated the need for running the electric pump in continuous mode as a safety measure, and as such, they did not provide a method for shutting it off.
It?s like pulling the Hoot Gibson circuit breaker on a 727 - most of the time not a problem. Sometimes, not a good idea?
1. We've lost a few 5 amp fuses. Part of the routine now is that we do CCiGARR
Close Canopy, Controls, Instruments, Gas (which includes installing gas pump fuse back in) Attitude, Radio frequencies for tower, Run up.)
2. The Rotax 912 ULS engine designers have an adequate fuel pump that feeds the Bing carbs with enough fuel pressure under all conditions, when running gasoline without Ethanol, as well as with Ethanol, up to E-15 IF fed by gravity with wings overhead that keep the lines pressurized. The RV-12 doesn't have overhead wings.
3. Van's saw fit, in their engine specs, to add a bunch of fuel hoses, a means of a pressurized return line back to the tank, and an electric fuel pump, to evacuate any vapor pressure that might result in vapor lock when a hot start under a hot condition MIGHT be created. By locating this above the engine, at the highest point in the fuel lines, and running the electric fuel pump, the vapor lock is avoided.
4. We only remove the fuel pump fuse with first cold start of the day, because we are on the ground, not in the air, the motor is cold, the oil pressure will be high, and the rpms once started will be low, so loss of any fuel pressure or fuel starvation is a non issue, since the motor is not running at or near full load or throttle. The load on the battery in these conditions, low temps, high resistance, and chemically speaking lowest provided voltage from the battery, are like a double or triple whammy on the peak capacity in amps on the battery, that it is capable of providing.
That's my thought process... the only time we blow fuses is first cold start of the day, so that's the only time the fuel pump fuse is temporarily removed, motor started up, voltage comes up, then reinstalled. We've never blown a fuse on reinstallation of the fuse into the fuse panel, yet. YMMV, this is the procedure we've been using, use it at your own risk and apply your own logic.