Confounding Diesel Problem - Looking for Ideas

[smurphny]

Is the self bleed system adjustable, cleanable? It must open when it expels air. An automatic bleed point might be susceptible to getting stuck. Just a wild guess. This thread should be saved as a troubleshooting guide.

[Tempest245]

Have you tried switching to a 10 micron filter..? You seem to have tried or eliminated most things, so just a shot..at something different..?

[SkiprJohn]

I'm in suspense! I keep checking this thread to see what you've tried and to see what the solution was. My first thought was a clogged return line but I'm kind of waiting to see what the real answer is going to be.
kind regards,

[Capitain Mike]

Originally Posted by SoonerSailor

I have a Westerbeke 44B with 280 hours on it in my Valiant 40. Since we purchased the boat, shortly after the re-power, we have had problems with the engine starving for fuel and often shutting down completely after 1 to 3 hours of operation - but not always. Sometimes I can throttle back to 1200 rpm and it will run happily there, but trying to push past that and the engine may stumble and die. After sitting for an hour or so, she starts back up and runs fine for another 1 to 3 hours. Switching between fuel tanks and between the dual Racor 500 filters makes no difference. Opening the fuel fills in case of faulty venting makes no difference. Tank fill makes no difference. Initially it was though to be biomass in the fuel, but that too has been eliminated and the secondary fuel filter on the engine remains clean. Four different diesel mechanics have not identified the real problem yet. Naturally, it never does this when the mechanic is on board.

The 44B has a self bleeding fuel system, and the engine mounted pump seems to be operating normally. We have two fuel tanks connected to a common vent. Each tank has a 3/8" fuel line going to a tank selector T valve. From there the fuel line goes to a pair of Racor 500 2 micron filters, individually selectable, thence to the engine fuel pump. Fuel return line from engine goes to a T valve to choose tank to return to.

Next step is probably replacing the fuel lines after the Racors.

So, any good ideas here? Why does it happen only after the engine has been running a while? We're baffled.

Chip

Hmmm
2 micron is a bit small and will increase the pressure required to travel through the filters
Try by passing the filters and use a bucket of diesel as was previously suggested. if you have a diaphragm in your fuel pump check it them work back towards the tank.
Replace all fuel lines that are rubber use 2 clips on each end of the fuel pipes
The point about the de-laminating exhaust is also very good.

Check the fuel needed to run the engine at various speeds then look at the filters flow through put per hour. the filters might be the only common connection. ( there is a fault whichever tank you use)

[James S]

If its not an obstruction in the fuel supply, I'm thinking, as has been suggested, that it may be combustion air supply. The intake air vent may be restricted or your air filter could be clogged.

[atoll]

http://www.westerbeke.com/ServiceBulletins/sb_175.pdf

might want to look at this as well,degraded or corroded power supply to the solenoid may cause intermittant problems such as this,but my money is on an air leak on the fuel supply line.

[MarkJ]

Originally Posted by SoonerSailor

a pair of Racor 500 2 micron filters,
Chip

**Belch** I love giving advice about the engin because I know stuff all about them

But I reckon Cap'n Mike may be on the path to money and glory.

Originally Posted by Capitain Mike

Hmmm
2 micron is a bit small and will increase the pressure required to travel through the filters
Try by passing the filters

My Racors have 2 micron filters in them but I've been told by the Yanmar Man (cousin to the Westy Man) that they should be 10 microns.

So if your've picked up some bad fuel, or a bit of bottom feeding gunk those 2 Microns may now be about 'alf a micron.

The only reason to use a 2 micron filter is to try and save your 2 micron final filter...

As Cap'n Mike says: Do simple before doing expensive.

Did he actually say that or did I just make up his advice?


Mark

[Capitain Mike]

Originally Posted by atoll

http://www.westerbeke.com/ServiceBulletins/sb_175.pdf

might want to look at this as well,degraded or corroded power supply to the solenoid may cause intermittant problems such as this,but my money is on an air leak on the fuel supply line.

As I said change the rubber hoses.

[Tempest245]

Originally Posted by MarkJ

**Belch** I love giving advice about the engin because I know stuff all about them

But I reckon Cap'n Mike may be on the path to money and glory.



My Racors have 2 micron filters in them but I've been told by the Yanmar Man (cousin to the Westy Man) that they should be 10 microns.

So if your've picked up some bad fuel, or a bit of bottom feeding gunk those 2 Microns may now be about 'alf a micron.

The only reason to use a 2 micron filter is to try and save your 2 micron final filter...

As Cap'n Mike says: Do simple before doing expensive.

Did he actually say that or did I just make up his advice?


Mark

IF The 10 micron fix works...I said it first....

If it doesn't...it was Mike's advice...

[Cheechako]

You could put an elelctric pump between t he tank and first filters. This is handy for filling fresh filter housings etc anyway. Also eliminates micro air leak issues etc. If that fixes it.... cool.... and now you know it's an air leak, (i believe you did check the pickup tube right?) if not, it's nice to have anyway and you know it's not a hose collapsing or air leak.!

[SoonerSailor]

The Racor 500 filters are rated at 120 gph, the typical 1 gph of the 44B doesn't develop a visible pressure drop across the 2 micron filters unless they are extremely dirty - which we haven't been allowing to happen. Since the teensy engine mounted filter is also 2 microns, but costs twice as much as the big Racor 500 elements, running 2 micron Racors makes more sense to me.

The most recent mechanic has told me that Westerbeke now recommends a 2.5 inch exhaust hose for this engine. The present hose is 2 inches, and of unknown age, so it will be replaced. Maybe this 2" hose is delaminating and obstructing as it gets hot. I'll also replace the hose from Racors to engine. Im afraid I wont have answers real soon. We are cruising with the family until next week. Then its back home and I'll have to let the mechanic sort it all out.

Im leaning toward an air leak that worsens as the engine compartment heats up, or delaminating exhaust or fuel feed hose. We'll look into the other suggestions if these dont pan out.

Chip

[Cheechako]

I was also told not to use 2 micron filters by a Diesel mechanic last year.

[MarkJ]

Originally Posted by Tempest245

Have you tried switching to a 10 micron filter..?

Dang! You did say it first! Post #32

[donradcliffe]

Changing your exhaust hose will empty your wallet and make the engine happier at full throttle, but the odds are its not going to keep it from dying.

[SoonerSailor]

When this problem first reared its ugly head - almost 2 years ago shortly after buying the boat, we did run 10 micron Racor 500 filters. There was a lot of biomass in the fuel at that time, and we were having to change blackened Racors AND engine filters frequently. Now the engine filter stays clean and the 2 micron Racors more slowly darken. We still change the Racors before the filter pressure gauge moves out of the black "OK" zone. Im convinced at this point that running 10 micron Racors would only mean much more frequent engine filter changes.

Separate lift pump? I'll keep that in mind.