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sailvayu · 18-04-2013, 19:13

you say you verified the pump turning with it off but i was talking about with it mouned on the engine. It is possible the the drive gear that drives the pump is broken. I cannot recall if it is a gear or chain on this engine i think it is a gear but it is possible it lost a tooth and will not turn the pump. A remote possibility I admit but you seem pretty convinced it is getting fuel and free of air and the pump has been tested to be working that does not leave a lot left other than the pump not being driven by the engine. Have to eliminate everything one at a time.

Dulcesuenos · 18-04-2013, 19:44

No expert but looking over the diagram of a westerbeke 40 it shows a fuel lift pump that is cam lobe driven. If it does have one have it did u check this? I would think an electric pump would bypass but you never know. Could be a worn cam lobe or bad pump diaphragm. Again not sure if its same engine.

sailpower · 18-04-2013, 19:51

Probably not it but when I first bought my Pearson 424 I had a very similar problem.

Eventually it was discovered that there was an inline fuel filter that no one knew about between the fuel tank and the motor and it was clogged. I had it removed and no more problem.

CaptainDana · 18-04-2013, 20:00

Open the bleed screw on the secondary fuel filter and use the manual lever on the lift pump to make sure you're getting clean, bubble-free fuel to and through the secondary filter. Then close he bleed screw. Having read the entire thread, that's the only thing you didn't mention doing. Then, loosen all fuel pipes at the injectors and crank till you get fuel leakage. Then it should start as long as it's cranking fast enough. Kinda sounds like you have a leak somewhere between the lift pump and the fuel tank and you're sucking in air. Good luck.

sww914 · 18-04-2013, 20:03

It is unlikely but the fuel pump drive shaft could break or cone loose from the drive gear and the two uneven surfaces just touching could make it turn without any strain on it but when the fuel pump is fitted it still wouldn't turn.
How does the engine sound when it's turning over? Do you know what a cranking engine sounds like with good compression and with bad compression on a couple cylinders?
Again, unlikely that you lost compression suddenly with a good running engine, but we're getting down to unlikely here.

**skipmac** · 18-04-2013, 20:08

You say you can see the shaft that drives the injector pump turning when you crank the engine with the IP removed. Is it possible that the shaft is turning with no load but when the IP is installed the shaft is loaded and not turning?

s/v 'Faith' · 18-04-2013, 20:11

Quote:

Originally Posted by CaptainDana

Open the bleed screw on the secondary fuel filter and use the manual lever on the lift pump to make sure you're getting clean, bubble-free fuel to and through the secondary filter. Then close he bleed screw. Having read the entire thread, that's the only thing you didn't mention doing. Then, loosen all fuel pipes at the injectors and crank till you get fuel leakage. Then it should start as long as it's cranking fast enough. Kinda sounds like you have a leak somewhere between the lift pump and the fuel tank and you're sucking in air. Good luck.

I might have suggested the same but for this in the OP;

Quote:

By passed the lift pump and secondary fuel filter by running a line directly to the injector pump with an electric fuel pump from Jerry can of fresh fuel.

In this configuration, none of the other fuel system components come in other then the ip, hard lines, and injectors.

-----

But, to the OP... When you did this, did each injector get cracked open to get the air out of the lines? In other words, did you bleed it when it was hooked up like this?

If so (at the risk of repeating) I don't see how it could be anything but the pump.

irwin37 · 18-04-2013, 20:47

Not a pro but just rebuilt my 4-108, It sounds like a fuel problem. First start after rebuilding gave me similar problem.

1 loosen banjo fitting the fuel filter
2 loosen bleed screw on the ip, have not seen this mentioned yet, there is a small bleeder screw on the on the top of the IP
3 loosen all fuel lines to injectors, both ends.

now while pumping the fuel lift pump, wait for all bubbles to stop at banjo fitting then tighten, continue to pump until all air bubbles stop on the top of IP, tighten bleed screw.

Now crank the engine and tighten each fuel line at the pump a bubbles stop, then with engine still cranking move to injectors and tighten them one at a time as steady stream of fuel comes out. (If now fuel comes out at the injector fuel line fitting you may have blockage in the high pressure fuel lines, could be junk or possibly water. If blocked remove each line and replace, if you can not replace clear with wire and flush with WD40. You should be able to blow thought them, flush witch WD40 if you do blow through them to clear any moisture afterwards.) You may need to do this in steps to let the starter cool down.

I have the rebuild manual for the 4-108 in PDF format if you need it. Shows were everything is.

Wonko · 19-04-2013, 04:37

Thank you everyone for the tips and suggestions. No silver bullet given, but I think the next step is to pull the IP and injectors and Bench run it with the injectors hooked up. If it runs there then I am thinking its the IP drive shaft that is gear run from th front of the engine. If it doesn't fire the injectors on the bench then its yet another bad pump.

I'll post back when I know for sure.

Thanks again!!

s/v 'Faith' · 19-04-2013, 05:10

Quote:

Originally Posted by Wonko

Thank you everyone for the tips and suggestions. No silver bullet given, but I think the next step is to pull the IP and injectors and Bench run it with the injectors hooked up. If it runs there then I am thinking its the IP drive shaft that is gear run from th front of the engine. If it doesn't fire the injectors on the bench then its yet another bad pump.

I'll post back when I know for sure.

Thanks again!!

Sounds like a great plan! Good luck!

**s/v Jedi** · 19-04-2013, 05:15

Check out that cam that drives the pump. It might have worn to the pointthat the pump still pumps a bit but can't reach high pressure anymore...

NCboatrx · 19-04-2013, 05:27

Quote:

Originally Posted by s/v Jedi

Check out that cam that drives the pump. It might have worn to the pointthat the pump still pumps a bit but can't reach high pressure anymore...

Jedi, The pumps used on the Perkins engines dont run off a cam. They are gear driven from the timing gears on the front of the engine.

**HappyMdRSailor** · 19-04-2013, 05:43

Wonko....

Well this sure is a mystery huh???? You will definitely figure out your fuel delivery problem with the next steps already mentioned....

1. Bench test IP with injection lines and injectors utilizing a drill motor
2. Utilize BRAND NEW known good fuel for your jerry can source and return lines. NOT JUST for the bench test, but for your next start attempt too....
3. I have had a previous problem with the above setup with the electric feed pump not pushing enough... Make sure your test feed pump is up to the task...
4. And finally... As others have mentioned... Suspect our stop lever... The stop lever on these IP's is connected inside to a "very weak" spring that pulls the stop mechanism inside the pump... I have had a pump that had the stop lever in the RUN position, but the spring tension was not overcoming the friction of the mechanism in the pump, leaving the insides of the pump in the STOP position.... This gave me the identical symptoms as you describe...

5. If all goes well with the above setup, and we actually have spray from the injector tips.... Drive gear in the engine has to be bad...

I will post a picture or two as soon as I grab them from another computer...