Diesel Fuel System Questions

[oakman]

So let's get a little more specific. We are dealing with a Universal Atomic diesel model 5411. 11 hp. I want to install a fuel water separator to the fuel system. I am going with the Racor 0120as. I also want to add an inline manual pump. Like the priming pumps for outboard engines.

Question is, do you think the mechanical pump can deal with the added elements. I would like to add the manual pump to bleed the system without turning the engine over. I have a feeling that fuel may not flow past the pump on the engine though. Also could the bulb style pump manufactured for gas, do well with diesel.

To see the engine in question check out this thread: http://www.woodenboat.com/forum/showthread.php?t=99070

Any thoughts, experiences appreciated.

Thanks
Oakman

[TerryLL]

I used that Racor filter on my diesel genset as the primary filter without any problem, plus a secondary filter at the engine. Change them both early and often.

There's not much restriction with those bulb-type fuel line primers. Seems to me they'd work just fine. No priming lever on the fuel pump?

[oakman]

No, unfortunately no priming lever. Manual specifies to turn the engine over with the decompression lever actuated, while watching the bleed bolt and closing it when air is out. Now switch in in cockpit, engine in hold. . . that's why I want the pump.

Thanks Terry

Oakman

[Todd D]

An outboard priming bulb will work just fine. You can move a lot of fuel with one of those. To be able to prime your diesel without turning it you need to have a bypass line after the filters around the injector pump to the return line if your engine doesn't already have the bypass. You can't pump through the injector pump. You can check to see if your engine has a bypass by installing the outboard bulb, disconnecting the return hose and then pumping the bulb. If you get fuel out of the return when you pump the bulb, you are good to goA a three way "T" valve in the fuel line will do the trick.

[Steve Duguay]

I had a 5411 in my previous boat. The engine ran great and never skipped a beat. It had a fuel system similar to the one you described: from the diesel tank there was a bulb for priming, that led to a Racor filter. I could change change the primary and secondary fuel filters and prime up to the mechanical fuel pump with the bulb. From there I would loosen the bleed screws in the system and use the decompression lever as described in the manual to bleed the system. It worked well, good luck!

[Breakaway]

You could also install a Racor duplex filter assembly allowing you to change elements without losing prime. And Racor's 400 series has a primer pump built in. I like these options as it results in one less break in the fuel line and so one less chance for your Universal to suck air.

[Norman Bernstein]

I had a 5411 in my first boat. Not my favorite engine... it was hard starting, especially when hot.

Anyhow, I never had to use the decompression lever or any cranking to bleed it... I just cracked open the bleed screw and switch on the fuel pump until fuel squirted out the bleed screw port, then tightened it down.... it always started after that.

I'd recommend a Racor water sep filter with the built-in priming pump... it's the easiest way to prime from the tank, all the way to the output of the filter... just unscrew the knob at the top and give it a dozen strokes or so, until the bowl is clearly filled with fuel, then tighten the pump knob.

[oakman]

Thanks for the suggestions. Just getting back from a day in the engine room, as it were. Much too late to be posting so I'll have to get back to you all later.

Don't have a lot of space for the filter and some of the other models get long.
I'll give them another look.

Oakman