Engine Losing Fuel Prime.

[cuthound]

My boat has developed a new fault which I am struggling to diagnose.

 

The engine is a Beta 43, which will no longer start when left for an hour or more, unless the fuel priming pump on top of the engine fuel filter housing is pumped until I can hear fuel returning to the tank. Once primed and started it will run faultlessly all day until turned off.

 

If this is not done the engine catches and dies after running for a couple of minutes.

 

If the engine is restarted within an hour of being stopped it catches, coughs and splutters for a few seconds then runs OK. 

 

Initially I suspected an air leak, although the revs don't rise as the fuel runs out, which is typical of an air leak into the fuel system. All fuel connections from tank to isolating valve, to WASP filter, to engine filter, to injectors are tight and the fuel lines seem sound.

 

I wonder if the priming pump is preventing the fuel from passing through unless operated first, although I cannot think how this can happen? I am reluctant to change it until I am more sure of the diagnosis.

 

Does anyone have any thoughts as to what else might be causing the problem? 

 

 

 

 

[nicknorman]

Slight air leak in the priming pump/filter housing. Well that is assuming you have the same filter housing as us with the large black button on top which is the priming pump? This was faulty on our engine when new, took a bit of diagnosing but a new filter housing /primer pump sorted it and 14 years later still fine. I think it was a slight leak on the shaft of the priming pump, too small to let diesel out but big enough to let a bit of air in. Or maybe something to do with negative vs positive pressure. Anyway, we had same symptoms.

Edited August 10 by nicknorman

[bizzard]

Old Ford Orions and Vauxhall Cavallier diesels had those pump filters, they were a pita.

[cuthound]

20 minutes ago, nicknorman said:

Slight air leak in the priming pump/filter housing. Well that is assuming you have the same filter housing as us with the large black button on top which is the priming pump? This was faulty on our engine when new, took a bit of diagnosing but a new filter housing /primer pump sorted it and 14 years later still fine. I think it was a slight leak on the shaft of the priming pump, too small to let diesel out but big enough to let a bit of air in. Or maybe something to do with negative vs positive pressure. Anyway, we had same symptoms.

 

Thanks Nick,

 

I surmised that it was most likely the priming pump, but didn't want to change it only to find it was something else.

 

Now that you and Bizzard have had similar failures I feel more confident that changing the filter housing will resolve it.

[David Mack]

Is your fuel tank the typical arrangement in the back of the counter? If so I suspect the problem will only show up when the fuel level is low. When the tank is full the fuel system will be under positive pressure, and with a leak diesel will leak out rather than air getting in.

[nicknorman]

3 minutes ago, David Mack said:

Is your fuel tank the typical arrangement in the back of the counter? If so I suspect the problem will only show up when the fuel level is low. When the tank is full the fuel system will be under positive pressure, and with a leak diesel will leak out rather than air getting in.

Our tank is under the engine, which probably made the problem worse.

[David Mack]

7 minutes ago, nicknorman said:

Our tank is under the engine, which probably made the problem worse.

Indeed. I have the same problem with Grand Union fuel tanks where most of the tank is below floor (and engine) level, but there is a relatively small triangular upstand at the front of the tanks. Fine to prime when the tanks are full, but difficult once the upstand is empty.

[nicknorman]

Just now, David Mack said:

Indeed. I have the same problem with Grand Union fuel tanks where most of the tank is below floor (and engine) level, but there is a relatively small triangular upstand at the front of the tanks. Fine to prime when the tanks are full, but difficult once the upstand is empty.

We have an electric lift pump below the engine, but still had the problem as described. Although if I left the electric lift pump running for a while before starting, we didn’t. But then there was the awful beeping noise!

[cuthound]

33 minutes ago, David Mack said:

Is your fuel tank the typical arrangement in the back of the counter? If so I suspect the problem will only show up when the fuel level is low. When the tank is full the fuel system will be under positive pressure, and with a leak diesel will leak out rather than air getting in.

 

Yes the tank is in the usual position, but is about 75% full.

[cuthound]

So this problem was resolved by replacing the fuel filter housing with it's integral pump, but then after starting the engine the boat began to smoke (unburnt fuel by the look of it) and leave an oily residue under the exhaust outlet. See photos.

 

Initially I thought it might be caused by the high concentration of Marine 16 that I dosed the fuel with. However after pumping out the old fuel (or at least as much as I could with my syphon pump) and putting clean fuel in the smoking persisted.

 

Eventually I bit the bullet and had the injectors overhauled. I put the overhauled injectors in earlier this week.

 

Took her for a test run this morning and she is finally running properly again.

 

As the smoking started immediately after I replaced the fuel filter housing with it's integral priming pump, I can only assume that the new filter housing must have has a tiny bit of swarf left in it after manufacturing, which found it's way to the injectors (only one looked heavily carbonised when they were removed).

 

Once Christmas is out of the way we will have a belated summer holiday on the boat.

[Tony Brooks]

Thanks for the feedback.

[nicknorman]

6 hours ago, cuthound said:

So this problem was resolved by replacing the fuel filter housing with it's integral pump, but then after starting the engine the boat began to smoke (unburnt fuel by the look of it) and leave an oily residue under the exhaust outlet. See photos.

 

Initially I thought it might be caused by the high concentration of Marine 16 that I dosed the fuel with. However after pumping out the old fuel (or at least as much as I could with my syphon pump) and putting clean fuel in the smoking persisted.

 

Eventually I bit the bullet and had the injectors overhauled. I put the overhauled injectors in earlier this week.

 

Took her for a test run this morning and she is finally running properly again.

 

As the smoking started immediately after I replaced the fuel filter housing with it's integral priming pump, I can only assume that the new filter housing must have has a tiny bit of swarf left in it after manufacturing, which found it's way to the injectors (only one looked heavily carbonised when they were removed).

 

Once Christmas is out of the way we will have a belated summer holiday on the boat.

it’s a bit ironic that the filter introduced contamination!

[ditchcrawler]

30 minutes ago, nicknorman said:

it’s a bit ironic that the filter introduced contamination!

Its one of the things that bothers me about cleanable filters. The risk of dirt on the wrong side when reassembling 

[cuthound]

12 hours ago, nicknorman said:

it’s a bit ironic that the filter introduced contamination!

 

Not to mention annoying and expensive!

[Bee]

To go back to the original post I have a Beta 43 which developed a starting problem. It would start, run for perhaps 20 seconds then die, that was probably just using fuel in the injector pump. If I unscrewed the fuel filter on the engine it was not full but about an inch down, if I filled the filter from a bottle of fuel then replaced it it would run OK, This looked like a lift pump problem so I replaced the lift pump - they are not repairable but cheap enough on E Bay, problem solved,  now runs perfectly. Those lift pumps will only lift about 18 inches or so.

[Tony Brooks]

14 minutes ago, Bee said:

To go back to the original post I have a Beta 43 which developed a starting problem. It would start, run for perhaps 20 seconds then die, that was probably just using fuel in the injector pump. If I unscrewed the fuel filter on the engine it was not full but about an inch down, if I filled the filter from a bottle of fuel then replaced it it would run OK, This looked like a lift pump problem so I replaced the lift pump - they are not repairable but cheap enough on E Bay, problem solved,  now runs perfectly. Those lift pumps will only lift about 18 inches or so.

 

I found that the valves on the disk type lift pump fitted on (some) Betas would clog their valves fairly easily, I suppose it could be bug related but did seem a bit fibrous. I found that if you put witness marks on the pump cover, central disk and body that could be stripped, cleaned and reassembled satisfactorily. No witness marks, and you only have a 1 in 6 of reassembling it so it works. Obviously no good if the diaphragm has failed.

[ditchcrawler]

27 minutes ago, Bee said:

To go back to the original post I have a Beta 43 which developed a starting problem. It would start, run for perhaps 20 seconds then die, that was probably just using fuel in the injector pump. If I unscrewed the fuel filter on the engine it was not full but about an inch down, if I filled the filter from a bottle of fuel then replaced it it would run OK, This looked like a lift pump problem so I replaced the lift pump - they are not repairable but cheap enough on E Bay, problem solved,  now runs perfectly. Those lift pumps will only lift about 18 inches or so.

I had that problem with my Landrover. If I came home from a week offshore and started it, it was fine for a few seconds, then I had to bleed the whole thing. After that I got int the habit of flicking the lift pump a few times before starting. Even now when we come back to the boat I do that before trying to start the engine for the first time, its just a habit now.

[Bee]

I think most of them are not take-apart-able except with a hammer and cold chisel and then they are not put-back-together-able.  There are (at least) 2 types, one with a lever that works off a cam and one with a roller. They are always on E Bay under Kubota and there is a roller type for £12.75 on there at the moment from the place where I bought mine. Mine was brand new and I guess it was removed from a new engine and that engine fitted with an electric pump for some sort of plant. Seems like a Kubota weakness.

[cuthound]

17 hours ago, ditchcrawler said:

Its one of the things that bothers me about cleanable filters. The risk of dirt on the wrong side when reassembling 

 

The filter housing I replaced was the one on the engine with a spin off cartidge filter, not the WASP filter which is in between the the tank and the engine mounted filter.  

Edited December 1 by cuthound
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