rookies fuel filter change.

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vasant

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Hi,
So this year i spared some time to perform fuel filter change on my own as i consider it vital to familiarize with engine maintenance.
I thought i did my homework pretty well RTFM and checked some youtube posts.
Anyway i changed the primary filter wich i had filled PARTLY with diesel before assmbling and i swapped also the fine filter which i filled completely.
Now the tricky part starts.
After reopening the shutoff valve on the tank i *expected* fuel would run into the primary filter squeezing the air out of the system up to this point. this didnt happen though and i assume that the filter being roughly at the same level of the tank didnt help much. So i started trying to prime on the lift pump but moving the lever didnt do much. Honestly speaking at this phase i hadnt checked in enough detail the manual about the fact that maybe moving the cranckshaft would help to make the pump work. But is felt like i was not pumping anything. It felt far too easy.
Anyway as the pump is not accessible very well i thought it might be a good idea to cranc the engine by hand. Same effect nothing ever happened. I never saw fuel comming out of prime filter.
I am not sure if i just were very unlucky and every time the pump was in the dead point of the cranckshaft or i should be more persistent. I acknowledge that the primary filter has for sure more than 100ml until it would be full, but still i guess that somehow fuel should come through.
any clue on what i am missing?? I would be happy to have a hand pump before the primary filter but the boat lived without it for 30+ years so i guess i am the problem here...


OF course the engine was working fine beforehand.....:ambivalence:
 
You are spot on about getting familiar with things on your boat, better to have problems now rather than at sea.
depending on your set up don't expect that fuel will run into your first filter, I thought that ( once upon a time) as that filter is lower than the tank. Many systems have a pipe in the tank and the fuel has to be sucked up this pipe and only then can it flow into the first filter.
My pump is between the two filters so I now close the bleed screw on the first filter and then use the hand lever to draw fuel through that filter and up into the second filter. The pump will feel 'slack' until the air is purged and fuel gets to the pump.
I hope this will help in your situation.
Quite possibly you may now have got air into the high pressure side and may have to bleed that which is another story of course.
It will help the experts if you can describe your set up in more detail.
Good luck
 
I hate to be simplistic but you do have the bleed srew on the primary filter open when you are trying to fill it by gravity from the main tank?
 
Yes sure. On the primary i actually removed it and tried to fill up from there. I guess i will try to find some tool to manually suck the air out. Like a vacuum pump
 
Some engines (like mine) are a bugger to bleed with the engine lift pump. The only solution we've found is to use a syphon pump (oil extraction pump) on the bleed screw of the secondary fuel filter. This seems to have enough puff to pull diesel from the tank and through the primary (separation) filter. Once all this is bled, then the high pressure side seems to look after itself.
 
Not sure i got what you mean. You say it will rather pump air in from the bleeding screw?
An pandroid mentions i could suck at the secondary, that would bleed also the system until there maybe.....
 
Is there a bleed on the top or bottom of the primary filter ?
If so you can use it to check whether the primary is filling.

How long did you wait for the primary to fill - it could take a while .

Is the fuel tank completely full ?
a full tank may help

You may be able to rig a Pela type pump onto the primary filter drain - if doing this then close the bleed screw on the engine first so the suction pulls from the fuel tank. This may get the flow going and then you can shut the primary filter drain and open the engine bleed screw and try pumping again.

Don't give up on the priming pump too quick - give it at least 10 minutes pumping as you may have a fair volume to pump.
 
Easiest thing is to permenantly install a diesel priming bulb ( as used on outboards) before your filters. Change filters open first vent and pump out the air then repeat on the second. Done!
 
Hi,
I have had a similar issue to you as my primary fuel filter is at the same height as the tank, i did the following which worked.
a) ensure the fuel tank is full to the brim, loosen the top of the primary filter to allow air to escape.
b) remove the fuel tank breather pipe from the the end where it exits the boat and blow hard this causes pressure in the tank and gets the fuel to flow to the primary filter. (it does help if there is a second person to close the filter when all the air is removed)
c) at this point you still need to get fuel to the lift pump. Open the bleed screw slightly and turn/ crank the engine until fuel reaches that far
d) pump the fuel lift and bleed each each of the injectors in turn.
There may well be an easier way but this worked for me and is the route i follow each time i disconnect the whole fuel system. Hope it helps
 
@wiggy: i guess thats the way to go. Would have to replace some lines though.
@ halo: 10 mins! Wow i didnt wait that much
 
Hi what engine have you got, my westerly has a VP 2003 easiest way to bleed that was to decompress the valves with the decomposition lever open the pled valve on the fine filter and turn the engine over as soon as the fuel starts coming out without bubbles close it and push the decomposition lever over and it would usually start, but the fuel did gravity feed to the first filter.
Good luck
 
Pagetslady said:
Hi what engine have you got, my westerly has a VP 2003 easiest way to bleed that was to decompress the valves with the decomposition lever open the pled valve on the fine filter and turn the engine over as soon as the fuel starts coming out without bubbles close it and push the decomposition lever over and it would usually start, but the fuel did gravity feed to the first filter.
Good luck
Click to expand...

yes i did that but i guess it was too late a s air already penetrated the system. the root cause was first filter not getting filled....
 
Thanks all for your replies.
HAving considered all above i understand the root cause of the failure was that i could not make sure fuel was filling the prefilter. pumping with the bleeding screw open probably just things got worse. So the way to go would probably be to have a manual bulp priming pump in the line.
As my line is copper i dont want to mess to much there so i guess i will proceed as following.
In the prefilter there si another unused inlet. Connect there a bulb pump and route it to a bottle with diesel . Pump up the diesel until primary filter and fine filter are filled. disconnect and proceed with bleeding injectors. This should help i hope i dont have to bleed the injector pump.....
Will keep up dated.....
 
Those of us with what is now considered to be an old fashioned method, namely taking fuel out of the bottom of the tank have none of this palaver. Old fashioned or not, gravity rules.

However, all is not lost, if you use your dinghy pump to slightly pressurise the tank, fuel will miraculously flow into your filters and out of the final bleed screw.
 
NormanS said:
Those of us with what is now considered to be an old fashioned method, namely taking fuel out of the bottom of the tank have none of this palaver. Old fashioned or not, gravity rules.

However, all is not lost, if you use your dinghy pump to slightly pressurise the tank, fuel will miraculously flow into your filters and out of the final bleed screw.
Click to expand...

nice idea as well! Will try to fit it to the tank vent! Thanks
 
RichardS said:
You'll need to bung up the tank vent first ..... unless you're able to use the vent to pump up the tank. I can't do that but it might be possible for some?

Richard
Click to expand...

I use the dinghy pump method if I'm getting low on fuel. I can transfer fuel from one tank to the other through the cross-levelling pipe. I plug the appropriate vent with a bit of rag and a clothes peg, and by wrapping some rag round the dinghy pump hose, can get a good enough seal into the tank filler. It needs two people.
 
Hi all,
Thanks for your valuable comments.
Issue was resolved today as following.
I went to boat equipped with a bulb pump and a racor that would match the prefilter additional inlets.
Once arrived I first started with disconnecting the breather pipe from the tank and started blowing. :-) immediately diesel ran out of the prefilter, shut this and opened the next one at the fine filter. This took a bit more but still after some time and more pressure it worked and a spectacular fountain of fuel jumped out. NExt we tried to crank and bleed the injectors without much success. I decided now to go by the book and bleed also the CAV pump. First screw was easy . for the second one some more cranking was needed. SO far I HAND CRANKED every time to have better control. after this was also resolved, screw Nr 3 and then also injectors after a short while were bled. after this engine started!! LEt it running 3-4 minutes i guess thats enough. Thanks again, like usually in life you have to blow to get things done...... :-) I have now a brand new bulb pump to sell.......
 
NormanS said:
Those of us with what is now considered to be an old fashioned method, namely taking fuel out of the bottom of the tank have none of this palaver.
Click to expand...

Only if your tank is mounted reasonably high up with the filter below it. My tank sits on the bottom of the hull; no matter where the pipe was connected, the fuel ain't going to flow uphill to the filter on the bulkhead above it.

Pete
 
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