bleeding fuel lines - learned something?

[9973720wb19]

I did the first maintance on my 4720 and after putting in a new fuel filter i could not get the engine to run. i followed the procedure in the OM (10 pumps and let the air out using the bleed valve) I did this for a very long time (something like two hours) with no progress in getting the engine to run - each release let out some fuel and air and I could not really build any pressure.

I noticed however, that right after I tried to start the engine, a greater amount of air and fuel came out than had been with using the pump alone. so I...while cranking the engine, I pumped the filter - the first time i got the engine to sputter (ahh at least something different). I did this about 3 times and it finally began to run. my take-a-way is that the engine helped move air from the line much better than the pump.

How do you guys do it?

 

[tomd999]

Hi,

When I change filters on my Diesels, I fill them up as much as I can with fuel before I spin them on. Less air to deal with.

My small Cummins B has a lift pump with a hand lever to prime the filter/water seperator, I leave the filter slightly off the gasket seal and hand prime it until fuel flows out then tighten it up and fire it off. It starts right up, then chuggs for a few revolutions as the air works out and then runs smooth again.

If you can prefill your filter, I think you will be in a better place next time.

Tom

 

[RippySkippy]

On my old iron John Deere (1020) has the same small finger pump...don't much care for it and there's a better way. On top of the filter housing there's a small nylon bleeder screw. After putting a new filter on, open the bleeder slightly, grab the air compressor hand valve and a clean shop rag. Push the shop rag in the fill tube around the hand valve, a couple of bursts of air, and it fills the filter up. Close the bleeder, crank and go.

 

[JD5210]

I second Tomd999 post about filling the fuel filter before putting it on. I also fill up the tank. At least for me doing it this way, I do not even have to bleed it inorder for it to start.

 

[9973720wb19]

Hi,

When I change filters on my Diesels, I fill them up as much as I can with fuel before I spin them on. Less air to deal with.

My small Cummins B has a lift pump with a hand lever to prime the filter/water seperator, I leave the filter slightly off the gasket seal and hand prime it until fuel flows out then tighten it up and fire it off. It starts right up, then chuggs for a few revolutions as the air works out and then runs smooth again.

If you can prefill your filter, I think you will be in a better place next time.

Tom

Tom - great tip...I'll do that next time. and btw, i did fill the fuel tank as OM said to do. I hope next time I can avoid a few less diesel showers! - had to trash my t-shirt. my 3720 with a Yanmar engine had elec. auto fuel bleed system...now I step "up"? to a 4720 with a JD engine and have a manual bleed??