DoI need to prime the fuel after...

[brico]

opening and replacing the primary filters?

I have just replaced primary filters and replaced one fuel pressure switch operating hour meter. I've refilled the filters with fresh fuel, but some fuel drained from the cylinder head supply hose and i am now in doubt whether i need to prime everything before attempting to start the engines.

And how much? Will i feel the resistance as I pump the fuel in? I will close the supply valve so I do not pump back to the fuel tank (not sure if this is necessary), but will do so nevertheless.

Or, will the fuel pump draw sufficient fuel and fill everything up? Manual says it needs priming, but I guess this is when major work is done and entire system drained of fuel and pump opened/removed for maintenance. The excess fuel flow apparently also helps remove any air in the system.

Any good advice is much appreciated.

[Boatsb]

Fire it up. It should bleed itself if everything is right

[dottieshusband]

+1 to What Scott said. Assuming refilled and good seals on the fuel filter housings, the air in the lines will bleed quickly.

[brico]

Unfortunately it did not work even though filters were full of fuel, i could not start either of the engines. Guess i will have to prim the system with fuel.

The engines run for couple of seconds and then died.

I have a spare "OUT" port on the filter head so i will try and connect some sort of a pump to prime it through that port. I believe this will push the fuel into the cylinder head/injectors as well as filling any empty space in the filter and fuel pump hoses.

Does westmarine carry such pumps or will i have to go to some specialty store? I believe even a simple hand operated pump will do the trick.

any advice is welcome.

[MikeP]

I recommend you install electric fuel priming pumps. It will change the PITA issue you are dealing with into a "flip of a switch and you're done" kind of deal. No need to ever pour fuel into a filter, just change them, turn on the priming pump and, 20-30 seconds later start the engine.

[brico]

Thanks Mike, much appreciated. Trust that priming pump should be plumbed to deliver fuel into the line after the fuel pump and towards the cylinder head/injectors?

I believe connecting it onto a spare "out" port on the filter head assembly that leads towards the injectors will fill up the system and may evacuate some air that is in it now.

[Boatsb]

I replaced the fuel lines and rebuilt the filters. Filled the filters and fired it up. Ran a little rough for a minute then smoothed out. You either have a leak or did not get the secondary filters primed.

[dsharp]

Par makes a small hand pump that works very well for the job. I started to tell you that if the engine fires throttle it up to 1000-1200 rpm. Pump fuel up to the head then tighten your lines. Get someone to give it a short whiff of starting fluid to get it fired off. Make sure your fuel valves are open. The fuel pump doesn't move much fuel at cranking speed.

[Milacron]

Thanks Mike, much appreciated. Trust that priming pump should be plumbed to deliver fuel into the line after the fuel pump and towards the cylinder head/injectors?

Can't say how the electric fuel prime pump is rigged on my prime movers (Detroit 12v71TA) as I've yet to need it (them)... but on my Onan 20Kw generator the electric pump is plumbed before the Racor primary filter. It has two ball valves (presumably one for "in" and one for "return") that are normally closed....so these must be opened for the primer to do it's thing.

I once (apparently) ran out of fuel on the port generator due to it's pickup tube being higher in the tank than the engines, and if not for that electric primer I don't know if I ever would have got the generator going again. Filling the generator Racor by hand and a gazillion pumps of the manual fuel pump resulted in nothing...not the first drop of fuel entering the secondary fuel filter. But a boost from the electric primer pump resulted in fuel at the injector entrance within 5 seconds and all was well.

My experience with changing the Racor primary and Detroit secondary fuel filters on the prime movers is no priming necessary. Changed Racor, added no new fuel...changed secondary and carefully poured fuel from old secondary into new filter, screwed 'er on and the engines fired up as they always do.... instantaneous with pressing the start button.

[brico]

so, i used small drill driven diesel transfer pump and run it few seconds through the spare port on the filter housing after which each engine fired right up. I guess it needed only little bit that i could not achieve just by filling filter elements since these hoses are after the fuel pump. It only took 30 minutes for both engines including firing and running them few minutes each.