Engine problem

[KrabKrusher]

Vega wirth Westerbeke 10 B 2. Has 2 fuel tanks, Racor at each tank, and the 2 original equipment fuel filters on engine.

A few years ago engine began to be hard to start, but ran well, good power, good exhaust color, gauges nominal. Had the injectors rebuilt but they were fine. I also had a mechanic replace all the fuel lines, thinking maybe it was sucking air, or that a leak was allowing the fuel to drop back into the tanks after a few hours of not running. (???)

Eventually I learned that with significant pre-heat the engine would start right up. The Westerbeke preheat also actuates the electric lift pump and I believe, but don't know, that I was in effect repriming the engine each cold start.

A few days ago I ran out of fuel in rough weather while heeling - no surprise - and switched tanks but engine wouldn't start. I know that rough sailing can kick up tank sediment, so the next day I checked each fuel filter. All were clean. I then ran the engine under load for 30 minutes and it ran well.

A few days later went for a day trip and the engine ran well but on the way back it cut out. Started right up. This had not happened before - the engine has always run well once it started.

But now it will start but not run. Gives every evidence (to this amateur) of fuel starvation: starts, runs up, then RPMs immediately drop off and it stalls.

I am convinced that the present problem is related to the hard start problem I started having several years ago, but I maybe I'm wrong.

The only part of the fuel system that hasn't been lately serviced are the tanks. I am careful about fuel - top off tanks in fall, use conditioner - but maybe the tubes that go into the tanks are fouled?? The engine was installed some 15 years ago and in my 10 years of ownership the tanks have not been cleaned. I have always had clean filters so I kind of assumed the tanks are clean too but maybe not.

Any ideas?

[Rachel]

I'm about as far as you can get from a mechanic, but... is there a chance your fuel pickup tubes have screens on the bottom of them? And so those are getting clogged instead of your filters? I wouldn't have a screen on the bottom of a pickup tube, but I believe they are sometimes installed by others.

Now I'll sit back and see what the actual mechanics have to say :)

Rachel

[mitiempo]

Rachel is right - pickup tubes shouldn't have screens but some do.

All fuel tanks have at least a bit of water in them. And the algae lives at the water/fuel interface. And when you put Biofor or similar into the tank it doesn't eliminate the critters, just kills them and they fall to the bottom to become black sludge. In combination with screens this could be your problem.

Or it could possibly be air in the line.

[Robert The Gray]

Could be two problems. Weak batteries that inhibit starting, and some disturbed sediment in the fuel that came later. My volvo penta MD7B
would turn over but never start when my battery was under charged.

r

[mitiempo]

Or a corroded connection.

[Chris Campbell]

One more thing to check: the return line from the injectors to the tank. I had a stalling problem with an old Universal diesel that went away when I installed a drop tube in the tank to attach the return line to. I've never quite figured out why that did it, since all it did was ensure that if the return line ran backward that it wouldn't deliver air to the injectors - and since it should never run backward it shouldn't have made a difference - but it did solve the problem - for me.

Good luck - diesels are the best when they're working, and seem the most mysterious when they're misbehaving.

[Zach]

If it is indeed a screen issue, you can take loose the fuel line and use compressed air to blow backwards into the tank. (Given you have a nicely vented tank...)

Temporary fix, but it will diagnose it if thats the problem.

[TRL]

My two cents on diesels:

On sucking air: The IP will generally overcome an air leak ONCE the engine is started. So, if its starting and then stalling, probability of an air leak diminishes. Doesn't mean there isn't one, just that stalling after starting because of one is less likely.

Not starting when cold but starting with significant preheating: Check compression. Scary thought, but comes into play with these symptoms.

Lift pump: Is it working? Sound alone doesn't mean it's pumping. Some diesels with lift pumps in the system start/run fine with a bad pump, some don't. I'm thinking running out while heeled could have put some major tank gunk up the pump intake. Does it pump fuel to the IP on prime?

Checking for leaks with compressed air: Good idea, but only use a FEW POUNDS of pressure. You can use the return line entry into the tank to gently charge the whole system with air. This will show any leaks on both the pressure and suction side of the system.

If you're getting fuel delivered to the IP, and have also ruled out air leakage and bad pump, then it's not fuel delivery. If your injectors are good, the place to look after checking for compression is going to be the IP itself.

Tom

[Rachel]

(Welcome to the forum, Tom, and.. nice post :)

Rachel

[ddsailor25]

I can understand why when you ran out of fuel that the engine didn't start and that was because you sucked air into the system. When switching over fuel tanks the lifting pump should of cleared the lines, but this might take a couple of minutes. The other area I would also check is the exhaust. If your getting alot of carbon build up in your exhaust riser then that will increase the back pressure and cause running problems. I think that even if the fuel tanks do have crud in them the primary and secondary finters should take care of it. If there is alge in the tank when you take the filters out they will be black.
So, check the exaust. If thats fine the next thing I would do is a compression check, but even if it's low it shouldn't stop the engine once it's running.
Diesel's are simple engines and there are only a couple things that can go wrong with them. Most of the time it's either an air or fuel problem. An engine taken care of can go well over five thousand hours of use.

[Rich P]

I know you've probably already checked, is the breather for the tank clogged?
That often allows the engine to run, but then cut out when a demand is put on it.. .

[JetStream]

One thing that sometimes gets overlooked, is that these small diesels with lift pumps have another filter. The lift pump itself has a filter on the inlet that rarely (if ever) gets checked for being plugged. The pump itself comes apart with a couple of bayonet prongs. The filter is generally sold with the gasket. Here is a link to the one for my Universal M2-12 Diesel:
http://www.marinedieseldirect.com/catal ... &comment1=
For engines with the lift pump and a fuel return, they are self bleeding so that leaving the ignition on will bleed the system. It sounds to me that you have a blockage problem. If it was air only, that would have gone away even before you shut the engine down (assuming no continuous supply of air into your system, like a major air leak). If you are stymied, disconnect the fuel hose at the injector pump and turn on the ignition with the hose going into a clean container. You should get a steady flow of fuel into the container. If the fuel is clean, you can return it to your tank. If the flow is very slight, or nonexistent, keep moving upstream until you find the fault. Hope that helps,
Bruce

[One Way David]

Given the symptoms you describe, I agree the problems are probably related. Some thoughts on diesel but not your engine make specific. My diesels are tractors and cummins and I may be way off here because of that, but...

A combustion engine is an air pump and a fuel pump with an explosion in between. I have always found it best, although time consuming and diesel mechs will say wastefull, to start at one end and test/check/clean/replace each component in the system.

Some diesels have 2 pumps, one at the fuel tank and the injection pump, as well as one or more filters and water separators. I don't know your engine, it may not be fuel injected.

I have had diesels that the fuel filter was good/new but the water separator was saturate or frozen (temp frozen) and it acted just like you describe.

Filters can be defective from the factory or be completely clogged but "look" clean.

I will refrain from describing in all the gory detail what I have found by disassembling the drain cock of the tank and .... It could easily star in The Blob XIII.

Check all lines but especially nonmetalic (rubber) lines. I have seen them look good on the outside and be crumbly gooy mess on the inside.

Check air intake filter and system.

ditto on exhaust, compression and other thoughts above.

I have had lift/injection pumps die and develop the same symptoms you are describing. Any good diesel shop should be able to test, diagnose and rebuild yours if needed.

As always, let us know what you find so we don't have to go through your pain and agony.

Dave.