Electric fuel pump

The engine -driven mechanical fuel pump on my IO-360 has failed, and I'm looking at replacing it with an electric one, such as the Andair unit.
Can I leave the mechanical one in place and simply bypass it or does it need fuel going through it ?
The other question relates to fuel flow vs pressure. The RSA injection system requires 28-30 psi and I burn around 70 litres per hour on takeoff. The Andair produces 30 psi and flows 64 litres per hour, and 150 litres per hour free flow or aound 5 psi.... Does this mean it is marginal at take off power if I need 30 psi and more than 70 litres per hour flow ? Or have I just answered my own question?
What have others done in replacing the mechanical pump ?

Replacing the mechanical pump with electrical would only be advisable if you have an independent emergency electrical bus and battery, to power one of the pumps. Else, you would have a common mode failure if your electrical system faults which causes the engine to fail.

I think some folks use the Andair pump with the 360 engines, but not in dual electrical pump arrangements.

You would need to remove the pump and then the drive rod from the accessory case, which you can only get out by removing the accessory housing. Leaving the pump on seems like a bad idea since a failure of one diaphram could result in an oil leak.

I'm curious what problem you're solving by eliminating the engine driven fuel pump? I understand that they are a hassle to change, but it seems like it would be a much bigger job to bypass it. Also, isn't the Andair pump about double the cost of a mechanical one?

As to your other question, I'm not sure what the rule is in Australia, but in the U.S. FAR 23 spells out the min fuel flow for reciprocated engines. Here's a partial cut and paste of FAR23.957 for reference.

"(c) Pump systems. The fuel flow rate for each pump system (main and re- serve supply) for each reciprocating engine must be 125 percent of the fuel flow required by the engine at the maximum takeoff power approved under this part.
(1) This flow rate is required for each main pump and each emergency pump, and must be available when the pump is operating as it would during takeoff;"

Thanks for the responses so far. One of the problems is that the replacement mechanical pump is nearly $4000 ( AUD) - even an overhaul kit is $1400 - whereas the Andair is $1300 AUD

I know the fitting of the mech pump is a real PITA but do-able, and would go this way if I could get a new or overhauled unit at a reasonable price.

I'm shocked at the pricing! Even accounting for shipping and exchange rates and whatnot thats in incredible markup. Aircraft spruce has it for $439 here in the states!

Might be time to look at the Spruce catalogue !

Cheers and thanks