I have taken a photo of my pump setup but having issues posting. If you want me to send please provide your email.

The set-up that i have is: fuel line from tank to fuel separator, 2 lines coming out of fuel separator, 1 line to mechanical fuel pump, other to electric fuel pump. Outlet side of mechanical fuel pump combines with the electric fuel pump and goes to the carb,
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I hope this is not too confusing. The photo will clear up the description. Please let me know if you have any questions.

PM sent..

Thx for the pic goin70 and all the responses from the group!

After speaking to the manuf of my mechanical pumps, and the responses I have received here, I think I'm going to shelve the elec back-up pump idea for now.
I'm having the mech pumps rebuilt. When they come back I'll keep a close eye on them. First hint of low fuel press though; I'll be revisiting the elec back-up idea again.

So what your saying is that you want it to come on automaticly if the mech pump pressure drops below a certain point? Now your getting into pressure switches in the fuel line between the pump and carb and elec pump would need to be plumbed in after the mech pump so it doesn't have to push thru the now broken mech pump.
Sounds like a nightmare to me and some serious overkill. Install some fuel pressure guges if your that worried about it and be done with it. How about an elc oil pump in case you have a drop in oil pressure?

Fuel press indicators are definitely on the list. Just wish someone made one with alarm capability,, kinda like a depth finder that has alarms for water depth being too shallow.

If oil press drops, chances are you got more problems than just a bad oil pump..

check out fwmurphy.com they make guages and alarms. might be someone close by, they do lot of ag/oil industry.

Hook a pro light or similar up and mount in dash so that when fuel pressure drops below set pressure it blinds you (figure of speech, but you definitely can't miss it). We used to run 2 in our boat, one for oil pressure and one for exhaust temp. Should have had one for fuel as in the end the mech pump gave up mid race and melted pistons and sent the metal through turbos. Never knew it was the mech pump until it went on dyno after rebuild and couldn't get fuel pressure up!

Why don't you just use a fuel pressure switch? When fuel pressure drops below 4psi it removes 12v from the ignition and shuts down the engine. When it removes the 12v it then turns on an idiot light on your dash using a normally closed 12v relay. Below 4psi and your ignition will be off and the bowls will dry up with the spark gone. $30 in parts.

Thx for the link. I checked it out and it looks like quality stuff. Unfortunately the lowest press switchgauge they offer is a 0-80 psi. Might work good with F.I. but not so good with a low press fuel sys. They did mention offering special switchgauges but would require a min order.

Sorry to hear abt the meltdown. One of my engs suffered a similar fate. Lucky for me it belonged to the prev owner when it happened.