Bleeding problems

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After replacing the primary and secondary fuel filters on my Yanmar 2GM20 I followed the instructions for bleeding, which involved opening the bleed screw on the second filter (on the engine) and operating the lever on the lift pump. The manual says to do this until fuel with no air flows from the bleed hole. But after a very long time and a lot of operating the lever there was nothing coming out of the hole. Could anyone tell me how long should it take to get the fuel flowing this way and if this isn't working what else can I try?

Thanks.

Will
 
You might have to turn the engine over (with the starting handle, and with the decompression lever open) so that you can actually move the fuel pump lever through its' full travel - sometimes the engine stops with the pump in such a position that it's impossible for the lever to move the pump diaphragm, in which case it won't pump any fuel.
 
Ensure the filters are seated properly to stop the ingress of air . it should only take a few minutes before you at least get spray . Check there are no kinked pipes , There is sufficient fuel in the tank and that its turned on where necessary ,
Paul
 
The situation described by SRP occurs when the pump cam is at full lift. Turning the starting handle half a turn will move it fully away from the pump actuating lever. Also make sure that you are moving the manual lever through its maximum travel.
 
Can take a long time to pump the fuel through. For a quicker result, get hold of one of those priming bulbs common on outboard fuel tanks, put some hose on the suck side, remove the last bleed nut, place the hose firmly over the hole and suck the fuel through. Works like a dream and in no time at all the fuel will be through. Then put the bleed screw back in and bleed with the pump as normal to remove any air.
 
[ QUOTE ]
get hold of one of those priming bulbs common on outboard fuel tanks

[/ QUOTE ] They don't suck awfully well but what would suck much more strongly is one of those vacuum oil extractors
 
I haven't quite got mine sorted out yet (MD11C) as it runs after bleeding but then cuts out after about 10 minutes - possibly a filter not properly seated and air getting in.
But, to answer your question, it takes about 15 - 20 minutes before I get fuel through to the primary filter and dozens and dozens (possibly hundreds) of pumps.
I love the idea about sucking it through and will give it a try.
TL
 
Thanks for all the responses, I had made sure that the pump was not restricted but I will also check that the filters are seated properly. I think the oil extractor attached to the bleed hole could be the way to go. Don't know why I didn't think of that because at one stage I was considering sucking it out myself!

I'll let you know how I get on.
 
We had a boat once which exhibited exactly the same symptoms every time I had to bleed the thing. My quick solution was to put a mole grip on the rubber breather pipe from the tank to seal it and use the dinghy pump with some rag round the nozzle to pressurise the tank through the fuel filler. It worked a treat and forced the fuel through the pipes and filters in a few seconds. Once fuel started to come through, then using the lift lever on the fuel pump worked as intended and I could finalize the bleeding of the system properly. The longest part of the job was clambering into the stern locker to put the mole grip on the breather pipe.

There were no leaks in the system, it was just that the fuel pump didn't like pumping air/couldn't get enough 'suck' when it was just air to pull the fuel through. And there was nothing wrong with the pump - it was brand new.
 
[ QUOTE ]
a mole grip on the rubber breather pipe ..................

[/ QUOTE ] Subject to accessibility of course I cant help feeling that simply presurising the tank via the breather would have been a "better " way. It would have avoided having to seal the filler with rags by simply leaving the cap on there. If it was something that had to be done frequently it would have been worth an alteration to the breather pipe run to facilitate it.

Perhaps I am missing something.
 
I had the same problem with my Yanmar 3HM35, it would take forever (at least 30 minutes) to bleed the engine filter using the lever on the pump. I solved the problem by fitting a hand priming pump on the outlet side of the primary filter. About £10 or so from ASAP Supplies, part number 302604. It takes less than a minute now.
 
I'm not sure about your engine, but my Volvo 2002 would bleed in every position except TDC, whereas my current 2030 will only bleed at one position, marked by a yellow paint spot on the flywheel. There is nothing in the owners' manual about it and you may have a similar situation.
 
Well I am back from the boat now, with a fully functioning engine! I used the pela oil extractor first on the primary filter, then on the secondary and it worked a treat. With the system full of fuel I tried the lift pump lever again but still nothing happened. Hand cranking the engine got fuel to flow out so I guess the pump is working but there is something wrong with the manual mechanism, the pump is also leaking so it definitely needs some attention.

Thanks for all the help.

Will
 
I had exactly the same problem when I tried to bleed my system with the tank level on the low side.

I did the same as you...used the dinghy pump to presurise the tank...

BTW I've been doing the same every spring for years to get the domestic water pump to prime when I refill the water tanks.

I now only change the filters when I have fairly full diesel load on.

Regards Nick
 
[ QUOTE ]
[ QUOTE ]
a mole grip on the rubber breather pipe ..................

[/ QUOTE ] Subject to accessibility of course I cant help feeling that simply presurising the tank via the breather would have been a "better " way. It would have avoided having to seal the filler with rags by simply leaving the cap on there. If it was something that had to be done frequently it would have been worth an alteration to the breather pipe run to facilitate it.

Perhaps I am missing something.

[/ QUOTE ]There might have been a better way if the breather was accessible. Unfortunately, the breather vent was in an even more inaccessible place than the pipe that connects the tank to the vent was. Mole grips to squeeze the pipe and seal it was the quick way of solving the problem.

I had to sail into the outer reaches of a harbour in S Brittany and perform this trick once as the fuel ran out when heeled and motor sailing to clear some off lying danger.

Anyway, I was just suggesting another method of getting fuel through to bleed and engine. People can make what they will of the (not totally original) idea.
 
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