Fuel Pump on my 97' Merc 4.3 LX Gen+....

So, my lovely Wife buys me a 1997' Reinell Rampage powered by a Merc 4.3 V6. We take it out to the lake and put 16 gallons of fuel in it, (does'nt even put us at a quarter tank....hmmmm...odd) we pull the kids around Alan Henry for two hours and this thing is running on fumes. What the heck? We smell gas...hmmm...not good. I trailer the boat and come home a little disappointed in how much fuel this beast uses and pull the plug to drain the little bit of "water" I saw under the motor at the ramp. As it's draining, I notice how stong the fuel odor is and think, "surely this is'nt fuel pouring out of my new boat?!" Stuck a stick in the stream....walked FAR away from the boat and lit the "water" logged stick...WHOA!! You guessed it....thats where all my fuel went. Tank is a 25 gallon aluminum tank that is mid-hull, under the fiberglassed in floor. Great. Not paying two-three grand to have the tank replaced...I'll fix it myself, right? Cut a perfect rectangle over ther tank, it's fiberglassed in...right against the hull. Did'nt feel confident enough to risk a hull breach cutting it out....so, I cut the top of the tank out thinking I'll mount a smaller tank inside it. Two pencil size holes in the bead of the tank, by the way...right at the forward end, at the bottom.

So, I order a 17 gallon Moeller marine tank, did'nt fit....because of the fill-neck...end up mounting it port side of the motor. Hook up sending unit, vent and fill lines...fuel line to my filter/seperator, patch floor, everything looks great. We head to the lake...splash the boat, start it up and putt to the dock....dies. for some reason...not getting fuel. Hour back to Lubbock....turns out, my fuel pump is'nt getting current. The plug the fuel pump plugs into...the blue plug with the black and grey wires? That should show voltage when the key is in the on position....right? The Volt meter reads ZERO...

I ran jumper wires to the battery off the fuel pump...ran like a charm. Now, can i run it like that? just unclamp the fuel pump from the battery when I'm not running? I know NOTHING about electrical schematics or harnesses....and really don't think I can correctly re-do a harness...or trace down why that blue plug is'nt powering the pump...there are no obvious spots along the line. Will the fuel pump burn up running directly off the battery?

Re: Fuel Pump on my 97' Merc 4.3 LX Gen+....

That's only a temporary repair. Since it worked before the tank change it's likely to be something easy. Disconnect the battery & have a look at the pump wires before you go to a repairman.
If it's too complex or you aren't sure of what to do then get a pro so you are safe. If you accidentally leave it powered it could heat up & damage the pump or wiring. That could be trouble, dangerous expensive trouble. Also, if there's any fumes in the bilge when you hook it up you risk an explosion.
As my friends in Minnesota would say, it needs fixed.

Re: Fuel Pump on my 97' Merc 4.3 LX Gen+....

NHGuy said:

As my friends in Minnesota would say, it needs fixed.

Click to expand...

Lol!!
Sounds like my "cronies" up at the "cabin" in the northwoods of Wisconsin...the "yoopers" on the other hand have a language of their own!

Re: Fuel Pump on my 97' Merc 4.3 LX Gen+....

You will only have 12v going to the pump when you are cranking the engine or the engine is running creating oil pressure. There's a oil pressure safety switch located right above the oil filter. Temporally jump these two wires together and you should have 12v at the pump.The idea of hooking the pump to the battery stinks!

Re: Fuel Pump on my 97' Merc 4.3 LX Gen+....

Ok...thanks. We took it out yesterday, ran great with the pump jumped to the battery anytime I had the motor running. Since I relocated the battery to the other side of the motor after the new tank install, I used longer cables, coiling the remaining cable and securing it with a zip tie beside the battery box. Probably 4 foot of excess cables...would that weaken the current so that the fuel pump isn't getting enough juice? I'm planning to inspect the wires off the pump and connection soon as I have more time...and if all else fails, jump that oil pressure switch for the next run. Appreciate all the help, Guys. Happy boating!!