Bleeding Conundrum! Know about Lift Pumps?

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StephenW

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Have a Vetus M3.10 diesel with primary and secondary filters. I replaced both filters and it took an age (1.5 hours) to bleed last time, though I didn't pre-fill the primary filter with diesel (lesson learnt!). Secondary cannot be pre-filled.

Wondering whether I could:
1. fit a screw-in hollow-tube fitting in place of the bleed nipple with some form of spigot for a plastic pipe
2. fit a length of plastic pipe
3. fit the new filters, pre-filling the primary with diesel
4. apply suction to the pipe to draw the diesel through

A few questions:
Q1. Will this approach damage the lift/fuel pump?
Q2. If such a threaded hollow-tube fitting exists what is it called so I can get one?
All help gratefully received
Stephen
 
We had a similar problem after fitting a Beta 35. it has a small lift pump which was ok when the fuel tank was full and the lift was only about 400 mm but as the level in the tank dropped to give a required lift of about 1 metre it took forever to bleed through. On checking with Beta they explained that the pump was only rated to lift a head of 300mm. Useless really. Their recommendation was to fit a small Facet electric pump between the tank and the lift pump and pump through the mechanical pump in addition we fitted a relay to energize the pump when the the ignition is switched on. bleeding through 2 filters now takes about 2 minutes. A much better system.
Jim
 
StephenW said:
Have a Vetus M3.10 diesel with primary and secondary filters. I replaced both filters and it took an age (1.5 hours) to bleed last time, though I didn't pre-fill the primary filter with diesel (lesson learnt!). Secondary cannot be pre-filled.
Click to expand...

Were you bleeding it by wiggling a little lever on the lift pump? If so, you should be aware that the lift pump is normally worked by a cam on the engine. If the engine stops with the cam in the wrong place, the lever does almost nothing. The solution is to rotate the crankshaft slightly with a spanner, so that the cam changes position. You should be able to feel that the lever on the lift pump is working better.
 
pvb said:
Were you bleeding it by wiggling a little lever on the lift pump? If so, you should be aware that the lift pump is normally worked by a cam on the engine. If the engine stops with the cam in the wrong place, the lever does almost nothing. The solution is to rotate the crankshaft slightly with a spanner, so that the cam changes position. You should be able to feel that the lever on the lift pump is working better.
Click to expand...
Yes. I don't know this engine, but the Volvo 2000 series will work at all positions except one, while the 20x0 series will work at only one position.
 
pvb said:
Were you bleeding it by wiggling a little lever on the lift pump? If so, you should be aware that the lift pump is normally worked by a cam on the engine. If the engine stops with the cam in the wrong place, the lever does almost nothing. The solution is to rotate the crankshaft slightly with a spanner, so that the cam changes position. You should be able to feel that the lever on the lift pump is working better.
Click to expand...

I also have an M3.10 and can second the above comments. I also fitted a priming bulb in the supply line so that I could force the fuel through most of the system before using the lift pump lever - it made a huge difference. I would also say look very carefully around the primary filter to make sure that air is not being drawn in around the seals (assuming you have a CAV type filter).

Yoda
 
StephenW said:
Have a Vetus M3.10 diesel with primary and secondary filters. I replaced both filters and it took an age (1.5 hours) to bleed last time, though I didn't pre-fill the primary filter with diesel (lesson learnt!). Secondary cannot be pre-filled.

Wondering whether I could:
1. fit a screw-in hollow-tube fitting in place of the bleed nipple with some form of spigot for a plastic pipe
2. fit a length of plastic pipe
3. fit the new filters, pre-filling the primary with diesel
4. apply suction to the pipe to draw the diesel through

A few questions:
Q1. Will this approach damage the lift/fuel pump?
Q2. If such a threaded hollow-tube fitting exists what is it called so I can get one?
All help gratefully received
Stephen
Click to expand...
I have the same engine and have had it for 20 years and done all my own maintenance. I have never had a problem with bleeding so am wondering what is different about your instalation that makes it so hard. I have the cav filter then the engine mounted filter. I bleed from the engine mounted filter while wiggling the lift pump (as long as that is off the cam) then just crank for a while and it fires. I can't work out how your proposed changes will work. Where are you bleeding the air from currently? Are you calling the filter the fuel passes through first the secondary?

Www.solocoastalsailing.co.uk
 
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I have dripless connectors on the fuel pickup lines just before the primary filters so I can pump fuel using my polishing rig from the low point take offs to back flush the pick up line. However, this also partially pressurises the system right through to the injection pump inlet. This makes refilling filters and bleeding a simple 2 minute task.
 
thanks to all for views. First (primary)filter is vetus cannister with top seal,so can be refilled with fuel. seconddary filter is engine mointed and point from which i bleed. Intention is to use a manual vacuum pump on the bleed position, but still unclear whether this would damage the internal diapragm in the lift pump.Thanks to those that mentioned engine position and lift pump effectiveness-became awre of this from the forum a while ago.Cheers
 
StephenW said:
thanks to all for views. First (primary)filter is vetus cannister with top seal,so can be refilled with fuel. seconddary filter is engine mointed and point from which i bleed. Intention is to use a manual vacuum pump on the bleed position, but still unclear whether this would damage the internal diapragm in the lift pump.Thanks to those that mentioned engine position and lift pump effectiveness-became awre of this from the forum a while ago.Cheers
Click to expand...

The way mine works, on a Yanmar, means that if there's a bit of fuel in the secondary it is normally enough to run the engine whilst any air is sent back to the tank via the return pipe, which is the topmost take off. Enough fuel gets through to displace the air in quite a short period of time. If your arrangement is similar and you have a full primary filter you may be able just to run the engine, especially if you stagger the changing of the filters.
 
Fitting an outboard type bulb pump in the line before the filters makes it far easier. Or an electric one if you fancy it.
Pushing fuel through the lift pump is no problem, it is essentially a small version of a diaphram bilge pump. Going the bulb pump route on a 1GM10, we bled it from dry in a couple of minutes. Water trap/strainer and engine filter, with the bulb between the two, though the bulb and the trap/strainer were below the level of diesel in the tank, which prob helped. The bulbs do pump air, so will pick up from a lower level.
 
Simplest & cheapest way is to get a diesel rated bulb pump. It will deliver loads of fuel, fill all the filters in a few pumps plus you will hear it force the excess fuel back to the tank on the return pipe.
I had problems with the lift pump, as you have, & not wishing to prime using the starter motor to turn the engine over, i bought the pump , stuck it in the system between the CAV/Delphi filter & the engine & solved the issue for good 4 years ago
 
I can third that with a M3.10 14Kva Generator.

My cav filter is on the pressure side of the pump though with a racor unit on the suction.

There are small electric pumps to replace the cam driven unit. Buy from a digger / small tractor/ HGV fridge repair firm to avoid the word marine.
 
Instead of the rubber primer pump hanging from the pipes, you can get a small alloy primer pump that fits onto the inlet of your primary filter. SSL Diesel Parts do them - about £9. Look in their 'Primers' section.
 
Small header tank. Failing that, a header tank. Or you could try a header tank. ( Yes I know it's not always easy, but honestly, lift pump that won't do 400mm, low mounted fuel tank, just trouble end to end.)
 
yotter said:
+1 for a outboard fuel line bulb pump, mine is fitted before the primary CAV (so pumps through both filters) on a VP2030D installation, wish I fitted it years ago:-)
Angus
Click to expand...

Just an aside: Volvo 2030 is, I think same as perkins Perama? looking at a boat with one, they seem to be a popular fit in many applications.
 
fisherman said:
Just an aside: Volvo 2030 is, I think same as perkins Perama? looking at a boat with one, they seem to be a popular fit in many applications.
Click to expand...

Indeed, in fact it is marked VP2030 on the top of the engine, but interestingly on the rear it is marked Perkins, made in England! It is painted a pretty uniform green, so sign of blue anywhere:-)
Angus
 
If your fuel tank breather pipe is accessible close the fuel filler cap and blow in the breather or use a foot pump to pressurise the tank this will force the fuel up to the filter and lift pump making bleeding easy.
 
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