Electric Fuel Pumps Before Racors on Trawler

[Steve Pope]

I have installed a squeeze bulb hand pump that is generic to outboard motors to prime the filter after changing / cleaning. works well.

[ATC]

Racors have a max on pressure - therefore the pumps are usally after the filters.

[Lancerbye]

When I purchased my boat it took me a while to find all the add on systems. This was one of them. I wondered for a while what the two switches were for. They were mounted right by the filters and when the switches were energized I could hear diaphram pumps running on the other side of the bulkhead. After tracing the lines and doing some investigation I found the very high quality diaphram pumps. They weren't needed to run the engines and were off normally so I figured they were for either filling the filters or bleeding the system. I have two Racor 500s and it is an absolute dream to change filters. They are there to fill and flush the filters. Don't be in too big of a hurry in taking them out if they are of good quality and properly installed. The quality of workmanship on the rest of the vessel should be a hint.

[kazenza]

Okay, so it sounds like I need to investigate further how these pumps are actually activated and that if there is a way to use them without the engine running to fill the RACORS and prime the system they may be worth keeping, but that I probably don't really need them. I am presuming they work off the ignition switch but need to follow the circuit as I just purchased this Boat and some of the "add on" elements like this don't seem to be fully functioning. I'm replumbing everything from the diesel tanks to the engines so trying to evaluate each element and simplify systems where it makes sense. Previous owner had one engine running off the main tanks and the second engine running off a day tank so I'm checking, cleaning and replacing to make sure the entire system is tight and clean. Thanks for all the information.

[Simes]

If you have the option then fit the Racor so that it is level with the fuel tank.
On board Talisman there are two Racor 500s (one at 20 Microns and one at 10 microns) both are fitted in such a position that when the tank is full Racors fill them self.

The Racor 500s run just fine with a little air in the tip (filter), better with all fuel but ok with a little air, portion on the unit.

When changing the filter as you remove one filter the new one should just about replace the same volume of diesel so the level should not change by very much. Again when fitting the 500s to Talisman I also fitted a Fuel rated stop cock to either side of the 500. I can now also stop fuel from escaping the filter whilst changing.

Simes

[Simes]

I have done a quick drawing of my installation should it be of help.
You can find it in my Gallery "Talisman of Fambridge and Friends". Only 2 pix in there so should be to hard to find.

Simes