Easiest way to prime a 12v71?

[scottinsydney]

I've run the aft tank to empty using the genset over winter months while on the mooring and waiting for the fuel barge due this week. I thought I previously switched the port engine to take fuel from and return to the forward tank but apparently did not.

What is the simplest way to prime the 12v71 motor please? Its 20 years since I last primed a Detroit.

There is one IN and two OUTs on the engine mounted fuel filter. I can also break the fuel line at the Floscan sender. There are electric priming pumps on board but not all the fittings so I'll go buy whats needed.

I'd like to know the simplest 12v71 priming process and where to plug in.

Thanks.

[davidwigler]

The generator pickup tube usually does not reach the bottom of the tank for this reason. Your engine should fire right up. The generator will have to be primed. Do you have a priming pump on the generator?

[scottinsydney]

Thanks David, but I need only to prime the 12v71.

Genset was working fine when last shut down. The aft tank is now empty and motor has run out of fuel.

How do I prime the Detroit please?

[dsharp]

I would take the “fuel in” line off the fuel pump and hook to suction side of the priming pump and hook the discharge line of the priming pump to the “fuel out” line on the fuel pump. Then crack the line at the cylinder head where the fuel enters. Leave it cracked until you have solid fuel. I don’t think you can draw fuel through the fuel pump but I could certainly be wrong. A hand pump might be faster. Par used to make one that I used for years . The lines are soft enough that you can clamp the hose down on a fitting without having to make it up mechanically. You can also fill all of the filters full and give the engine a whiff of starting fluid to fire it off. The “purist” may turn there nose up to starting fluid but as long as you don’t go crazy it’s not going to hurt anything and it’s a lot easier on the starter.

[racclarkson@gmail.com]

Do not use ether. Don’t do it. You can go in or out at each secondary per the attached picture; you need a ball valve anywhere between the two. Start the good motor. Wait until fuel pressure equalizes between the motors if you have gauges installed. Otherwise, let good engine run at fast idle for a couple of minutes then crank the unprimed motor. Close valve after a minute or so. No need to crack any lines. The air will be carried away in the return. And the lines around the fuel pump and the head are a pain to get to. L

[rsmith]

Shut the valve to the tank. Fill the primary filter then tighten the lid. Open the valve. While someone is cranking the engine loosen the lid on the secondary filter. When you see fuel pouring out tighten the lid and your good to go.

[racclarkson@gmail.com]

Or do the cross feed and change secondaries dry. Why spill fuel when the good engine will fill the filter and purge the lines on the starved motor with the opening of just a single valve. Very simple with added benefit both engines can run off one motor’s fuel pump output should you lose a pump or clog a line running a tank dry.

[dsharp]

Contrary to the drama queen’s opinion there’s more than one way to bleed an engine. You can use the running engine to pump fuel to the non running engine or your priming pump. Lots of ways to do it.

[Pascal]

The easiest way Is to get a small electric fuel pump (pretty much any will do). Undo the fuel hose at the racor outlet and insert the pump. Don’t sweat the connection. I usually clamp a piece of rubber hose over the fitting on the fuel line. Run the pump for a while then disconnect and fire it up

You can also do that with the brass utility push pull pump. One time I lost prime Due to a fuel pump
Issue and didn’t have a pump. I had some hose so I ran a hose from the generator lift pump outlet and got home like that

[dottieshusband]

Scott, lots of opinions on this. To me, the simplest way is to fill the racors and the spin on or canister. The remove the side lug from the canister or spin on mounting bracket and screw in a manual pump... about any kind will do, and pump in diesel fuel.. replace the lug and crank. Unfortunately the fuel pump on the 12v71 isn't a lift pump and is not good at self priming. Even something as simple as this will work.