RLW

Thanks Blown 1500,
I am presently running a mechanical fuel pump. Have you ever heard of wiping out the cam lobe that drives the mechanical fuel pump due to to much spring pressure in the pump? It just happened to a friends motor when dialing it in on the dyno. It was a Holley pump. New roller cam.

convincor

I have seem some cam manufactures recommending there fuel pump push rod for use with there cam.

Back4More

I tried a set of Red Holleys in addtion to the mech. for safety.
It was a pluming mess and just chewed my Batteries down.
Took them off......
I would just run a mech. set up

Raypanic

I had a little problem the other day with my fuel pump circuit. I kept on blowing the 15A fuse in my merc wiring harness. I called aeromotive and they said my A1000 pump pulls about 13 amps at 45 psi. I changed it to a 20Amp and now it works fine.

In talking to Aeromotive they suggest not using the std merc wiring harness for the power because the wires are too small. They recommend a 10 gage wire coming from the battery but being controlled by a 30A minimum relay which is controlled by the stock fuel pump relay.

It should be easy to wire up I will just take the fuel pump wires off the existing pump terminals and wire to the coil wires of the new relay. Then wire the 10gage wires through the relay to the pump. I will also put an in-line 25A (aeromotive spec) fuse in the 10 gage circuit.

The problem I have now is finding a "marine" relay that is rated as explosion proof.

convincor

Do they make a relay that is specificly made for marine?

Keith

Glad I found this thread, albeit too late. I still have a few questions.

My mechanic installed Holley Blue Marine pumps with regulators, setup for 7psi to Holley 800's on a Gen VI 502 with Dart H/R intake, and wired it directly to the coil. See this thread, just part of the reason why it should not be installed that way.

Painless Wiring makes a universal relay for a fuel pump, but I don't believe it's specifically for "marine" use, and I'm not sure what the mechanic is installing as a replacement, but I want it done properly and with the right parts.

Given the fact I now own 2 Holley Blue's, I'm going to stay with those but I'm unclear on the wiring piece, specifically how it ties in with an oil pressure switch. This would seem to keep the engine from starting in the first place, unless cranking builds up enough pressure in a second or 2. Right now I'm used to simply turning the key and it starts up immediately. An oil pressure switch with 3 wires (Common, Normally Open and Normally Closed loops) is what I would think he'd need, is this correct?

There is also an additional fitting/nipple on the pumps (it's a very small diameter), there is no hose attached to it. I'm assuming this is some sort of release valve, and a line must be run from it back to the tank, or to the carb?

Thanks in advance.

convincor

I'm going to use the painless kit. All the parts are sealer and the connections are going to get covered with liquid neoprene.
With the wiring, there should be a wire from the starter relay to the pump, so when the engine is being cranked there is power to the pump. when the key is released, that power is shut off and power from the oil pressure switch will take over.
The small port your referring to, I believe is what is used to adjust the buy-pass pressure in the pump. If you don't use a return line, this keeps the pump from building to much pressure.