How is this working?

[SeeMonstrEd]

Hello,
I need some advice. I have owned my boat for more that 2 years and have sailed her more than 2000 km. My perkins M90 (4.236) has always run like a champ, starting immediately even with some crud in the old tank.

I recently replaced the secondary Racor fuel filter and cleaned the bowl. I got some air in the system so I started the bleeding procedure. I have changed the Racor filter many time and never had to bleed because I didn't clean the bowl.

When I went to bleed the system I noticed that the lift pump is not even connected into the system. The fuel line comes straight from the tank to the Racor. Then straight from the Racor to the primary filter. There is a nice shiny new looking lift pump on the engine but it is not hooked to anything.

My question: Should I hook this into the system? If so does it go before or after the Racor?

Thanks in advance

Capt Ed

[belizesailor]

Is your fuel tank higher than the engine?

Is there an inline electric fuel pump somewhere?

[Privleoplag]

Originally Posted by SeeMonstrEd

Hello,
.... If so does it go before or after the Racor?

Thanks in advance

Capt Ed

Racors work best on vacuum. If you use the pump, install after the racor.

[SeeMonstrEd]

I did find an electric fuel bump after the Racor. It looked strange so I didn't recognize it at first. It is made by Facet. It looks more like a filter than a pump.

The Fuel tank is lower than the engine and the rest of the fuel system.

I did finally get the air out and it is running now.

I am still wondering if I should connect the mechanical pump too.

[Lepke]

A common fuel system for diesel engines is placing the primary filters low (like Racors) so they fill by gravity when changing filters. Then a vacuum gauge (so you know when they're getting plugged), next the lift pump, and then the secondary filter. Usually the primary filter is 30 microns and the secondary is 10 micron. All boats I've run or owned had 2 primaries so you could change filters with the engines running. Some people change the mechanical lift pump with an electric pump because it makes bleeding the injector pump easier. Some have an electric pump just used for bleeding.

[MickWay]

I had a problem with my M92B stopping. I eventually traced problem back to a loose wire in terminal strip that supplied 12 volts to lift pump. Once tightened up no more problems. It needs to be working, my fuel tank is higher than engine so just gravity feed was not sufficient

[DeepFrz]

Its not necessary to put your mechanical pump in line. Make sure you have a spare electrical pump though.

[Mithril Bham]

I like to hook up the mechanical pump and use that turning the electrical off and only using electric for bleeding. That way when the mechanical pump fails you can switch to the electrical until you have a chance to replace it. I also have two primaries but only use one at a time.