Westerbeke W50 Injection Pump Leaking

[felizcortez]

I started our engine on the hard today in anticipation of splashing. I saw diesel leaking right after starting the engine (showering down) so we shut it down. I traced the leak to a small weep hole a the front of the injection pump where the pump mounts to the engine.

After starting the engine a few more times, the leak was much smaller and was no longer showering down. I took a video and put it on youtube. You can see the diesel starting to flow after the engine starts vibrating.

https://www.youtube.com/watch?v=s6jhVZT5ihc

I have also included a picture of the bottom of the pump where I have circled the weep hole.

What causes diesel to leak out of the weep hole? I'm assuming it is probably the front seal that goes into the engine, but i'm not too familiar with the pump.

The info on the pump says DPA 3342 F710. I haven't been able to find much information about this model on the web.

I'm assuming I need to take the pump to a diesel place to get the pump rebuilt. I think I can remove the pump, but am a bit worried about getting the timing correct during reassembly.

Any tips or thoughts would be helpful.

[Lepke]

If you know what company made the base engine, the injector pump should be the same. And cheaper from a farm/industrial/ auto parts store than Westerbeke.
There may be a Youtube video of timing the pump. Better injector pump rebuild shops often have info on removing your pump and timing after rebuild.

[tkeithlu]

Ditto on other sources of the pump if you need one - Westerbeke didn't make it, so find the "shelf" it came off.

Reassembly alignment- Use scratch marks on the shell and on the moving parts as you disassemble, plus photographs if they will help. It sounds like a leaky oil seal - go get one from MacMaster-Carr:

https://www.mcmaster.com/oil-seals

[felizcortez]

The info on the pump says DPA 3342 F710. I haven't been able to find much information about this model on the web. The westerbeke w50 is based on the BMC 1.8L out of the UK. I looked at calcutt boats, but the model numbers on their injection pumps don't match up.

What would cause the weep hole to leak diesel? Is it the front seal that goes to the crank or something else? The pump was rebuilt about 4 years ago and 550 engine hours ago.

[svthreecheers]

Originally Posted by felizcortez

The info on the pump says DPA 3342 F710. I haven't been able to find much information about this model on the web. The westerbeke w50 is based on the BMC 1.8L out of the UK. I looked at calcutt boats, but the model numbers on their injection pumps don't match up.

What would cause the weep hole to leak diesel? Is it the front seal that goes to the crank or something else? The pump was rebuilt about 4 years ago and 550 engine hours ago.

DPA 3342 F 710 is the part # of the Pump for parts list and Test Specs
They are made by LUCAS C.A.V - now called DELFI

Any Fuel Inj. Shop should be able to fix that fuel leak caused by worn
Pump drive shaft or defective drive shaft seals (2)
Cheers

[skipperpete]

Hi Felixcortez
I searched my pump overhaul manuals for details of that little weep hole and finally found an old post on “Smokstak” from a guy with exactly the same problem.
On the front shaft of your injector pump there are 2 oil seals and that drilling goes through the mounting flange and into the gap between the two seals so that when either of the seals fail the fuel ( or engine oil depending on which seal leaks ) can’t cross contaminate. It’s quite rare to see this weep hole, most Dpa pumps don’t have the drilling.
One cause of that fuel side oil seal leaking is high case pressure build up from the metering pump and it usually happens because the pump return line is severely restricted or totally blocked either by dirt or by a valve not selecting properly in the case of multiple fuel tanks with a return line manifold.
Cheers , Pete.

[felizcortez]

Originally Posted by skipperpete

Hi Felixcortez
I searched my pump overhaul manuals for details of that little weep hole and finally found an old post on “Smokstak” from a guy with exactly the same problem.
On the front shaft of your injector pump there are 2 oil seals and that drilling goes through the mounting flange and into the gap between the two seals so that when either of the seals fail the fuel ( or engine oil depending on which seal leaks ) can’t cross contaminate. It’s quite rare to see this weep hole, most Dpa pumps don’t have the drilling.
One cause of that fuel side oil seal leaking is high case pressure build up from the metering pump and it usually happens because the pump return line is severely restricted or totally blocked either by dirt or by a valve not selecting properly in the case of multiple fuel tanks with a return line manifold.
Cheers , Pete.

So you think I might have a blocked return line? The engine runs fine other than the fuel leak, would there be any degradation in performance caused by a blockage? What is an easy way to check for this? Just pull the return line off the injector pump and then blow air through it?

I'm having trouble finding any information on the 3342 F 710 online does anyone know where I can find a potential pump in online inventory?

I called TAD on the east coast and they mentioned they have the 3342 F711 in stock available for an exchange ($795) plus core charges. They said the
F711 is the newer version of the pump. I'm still trying to piece together what each piece of the part number means.

Are these the two seals that usually fail?

https://injectionpumps.co.uk/product...in-seal-pumps/

Are these user replaceable

[skipperpete]

The seals in your link look about right BUT there are as many configurations of CAV/Lucas/ Delphi distributor type pumps as there are flavours of Ben and Jerry’s ice cream and it’s usual to compare the replacement seals with the resident seals at the time of overhaul.
I don’t believe it’s wise to do your own seal replacement, partially because the inner seal is only replaceable from inside the pump housing which requires a substantial amount of dismantling but mainly because the pump needs to be run and checked for leaks and calibration after re assembly and this is best done on a dedicated test rig.
Yes, a blocked or restricted return line is one of the possible causes of a leaking front seal, the little vane pump in the pump head puts out quite a bit of pressure and the case is de pressurized to some extent by the return line drilling just near the weep hole in your video.
Pete.

[felizcortez]

I called a few more places in the states and I can get the pump rebuild for around $800-$950.

If I remove the pump and get a remanufactured one and swap it out for the core charge I'm assuming setting the timing will be much more difficult because I won't be able to use scribe marks on the old pump. Any advice on this? It is probably faster to swap out to a new pump than it is to rebuild the current one I have.

[felizcortez]

Originally Posted by skipperpete

The seals in your link look about right BUT there are as many configurations of CAV/Lucas/ Delphi distributor type pumps as there are flavours of Ben and Jerry’s ice cream and it’s usual to compare the replacement seals with the resident seals at the time of overhaul.
I don’t believe it’s wise to do your own seal replacement, partially because the inner seal is only replaceable from inside the pump housing which requires a substantial amount of dismantling but mainly because the pump needs to be run and checked for leaks and calibration after re assembly and this is best done on a dedicated test rig.
Yes, a blocked or restricted return line is one of the possible causes of a leaking front seal, the little vane pump in the pump head puts out quite a bit of pressure and the case is de pressurized to some extent by the return line drilling just near the weep hole in your video.
Pete.

I reinstalled the pump yesterday and it is leaking worse than before from the weep hole. I'm checking with the place that rebuilt it here in Mexico to see whether they actually replaced the shaft seals. Frustrating. I also tore apart the return line to check for blockages. It was difficult to blow through with my lungs and I traced that back to a check valve mounted on the secondary fuel filter. I removed the valve and blew compressed air through it and it opens under pressure. I think the check valve is working fine. Everything else is free and clear to the tank.

So now I get to remove the pump again. The saga continues.

[skipperpete]

There should be very little return line pressure for a CAV DPA pump and a spring loaded non return valve acts as pretty solid restriction to flow and subsequent pressure increase. Try it without the Non return valve and see if the leakage problem remains. “Parker” make a springless gravity activated one way valve that must be installed vertically and has extremely low resistance to flow.
Pete.