Diesel Engine Cutting Out

[Chuck34]

Originally Posted by ausnp84

Ok, thanks all.

Next:
4.) Engine fuel filter to be replaced
5.) Fuel vent line to be checked and tested
6.) Fuel return line to be checked and tested
7.) Lift pump to be replaced

Update to follow!

N

Ok, only check one thing at a time and start with the easiest/cheapest and work your way down the list.
Easiest...remove cap from fuel fill to test your vent.

[NYSail]

Did you blow back your he line into the tank?? Make sure pick up is clear??

[Russ]

Been through this painfully. The group has given you good advice and I did all that the first time around and it did not solve anything simply because I had an undetected air leak that I had looked for and missed.

BEFORE you replace all that stuff one-word: AIR as in air leak.
You mentioned an air leak and I strongly suggest you haven't found the leak. They can be very painful to find and often as in my case allow the engine to run for hours and then it stops.

Remember the engine pump is a vacuum so you may not see the leak as it is SUCKING air and no fuel my drip.

1) wrap every joint/fitting with a small piece of paper towel
2) get a small fuel pump and PUMP fuel into the system from the first access point after the fuel tank. ( as opposed to having the engine fuel pump suck fuel.
3) The paper towels will pick up the leaked fuel and you'll find the fitting that is air leak.
4) Yes it is a PIA but works

If you need more: <svascension@yahoo.com> Russ

[Jason Flare]

Originally Posted by Chuck34

Ok, only check one thing at a time and start with the easiest/cheapest and work your way down the list.
Easiest...remove cap from fuel fill to test your vent.

A lot of great advice in this thread but I especially like Chuck34’s advice, above.

One thing at a time.

Just yesterday I solved a few problems with my diesel generator.

I had a combination of problems. One problem was a broken wire on the electric fuel pump which caused it to occaisionally starve for fuel.

The next problem was a tiny leak at the inlet fuel line on the primary filter allowing just enough air into the line to cause very similar symptoms as the intermittent fuel pump problem.

But I ran down the checklist one item at a time, including taking the fill cap off to check for a plugged vent, blowing down the hose into the tank to see if I had clogged the fuel pickup with junk.

I had multiple issues with the engine but I tackled one fix at a time.

I’m not that smart that I can fool with a few things at once and come up with a diagnosis.

Great thread OP. You’ll love it when it’s running like a champ.

[GinTonic]

Check your Fuel tank , you will most likely find an algae crud jelly pie settled in the bottom of the tank , right were the fuel intake is located , if the fuel intake has a "mesh" , the crud will stick to the intake mesh screen when the fuel level is low and you are sailing calm seas.

This crud is formed by water condensation inside the fuel tank , some diesel tupes have bio diesel components and the algae crud grows inside the tank.

You will need to open an inspection hatch , remove all the fuel and clean the inside of the tank completely.

On my Beneteau Ocanis , it was a Plastic tank , totally seqaled and we had to cutout a 4.5" inspection port with a holesaw to solve this .

Originally Posted by ausnp84

Hey guys,

Need some help with my starboard engine.

Issue started with it hunting, then cutting out. Marine engineer said it was water in the diesel so his solution was to run fuel in / return lines to a jerry can

Reconnected engine, filled up the tank with fresh diesel and it worked for 3hrs then started hunting and cut out. We could see air coming into the racor so tightened it all up and it literally worked for 3hrs again and cut out. Annoying to say the least.

Today I swapped the hosing to the racor and engine, swapped out the racor filter and seals, primed the engine and after a few attempts, got it running for 30sec/1min then it bogged and cut.

Now the engine starts every second key turn and runs for 30sec/1 min, bogs and cuts.

Thoughts? I’m going to swap the fuel filter, but am thinking it could be a lift pump issue and the engine only getting the fuel between itself and the lift pump (generated during the ignition process), hence the short run each time.

Anyone else have a similar issue? Engine is a Lombardini LDW 1204SD for reference.

N

[mlydon]

I had a similar issue with a westerbeke with CAV-type on-engine filter. The gasket wasn’t sealing correctly, so very occasional hunt and die.....

Matt

[Jason Flare]

GinTonic brings up a good point that it could be crud in your fuel tank.

Another way to check for this is to pull fuel out through your pickup tube and have a look at it.

If the fuel’s cruddy keep pumping until you have good fuel, then, if you can, slide a hose slightly smaller than the inside diameter of the pickup tube down to the very bottom of the tank and pump that out. (It helps to cut a slight bevel on the bottom of the hose.)

FYI this works. I’d did this four years ago in Fernandina Beach and have been to Key West and back to CT each year since. I’ve done about 10,000 nm since the cleaning.

I use Startron enzyme fuel additive FWIW.

[ausnp84]

Thanks guys, an update as promised.

The fuel’s new and the tank’s been cleaned, so definitely wasn’t that.

I ended up disconnecting the diesel return and running it into a bucket (good flow btw) but no joy.

Swapped out the lift pump and it starts easier, but the problem remains.

In the end I’ve had to call in the engineer as I also want the timing belt checked / changed. Luckily they’re the same guys who supplied my last engines and are happy for me to watch all the work / learn what to do next time, so the next update should hopefully provide the cause and fix!

N

[wtmf]

I had water in the fuel. changed filterS and fuel and after bleeding the line everything worked fine.

[zeseb]

It took me 1 year to figure the same issue out after buying my boat with a Yanmar engine. It was due to 2 things;
1- I have a fuel tap between the CAV filter (first filter) and the fuel tank. Some little pieces of plastic were stuck in the tap. Then the fuel could’ve flow efficiently into the engine. That’s why I could start it, but as soon I put more rpm, the engine stopped. Wait a bit and it could start again, because a bit of fuel dropped down the line and stopped again. As I have a day tank, it’s falling by gravity to the engine so when the level of fuel wasn’t enough, not enough wEight and the flow wasn’t enough to go in the rpm neither. So I also got some bubbles and air in the 1st filter, because not enough fuel going in basically.
2- the fuel was fully contaminated and turned into orange, with some organic brown bits in it; so I emptied the tank, cleaned inside.
It was a total nightmare but your engine is definitely not the problem.

[Jason Flare]

Originally Posted by zeseb

As I have a day tank, it’s falling by gravity to the engine so when the level of fuel wasn’t enough, not enough wEight and the flow wasn’t enough to go in the rpm neither. So I also got some bubbles and air in the 1st filter, because not enough fuel going in basically.

You should never get air in the fuel line for any reason.

Fuel flow problems should never introduce air into the system.

(Unless you’ve run out of fuel and sucked in air.)

If you’re getting air in the fuel that is a separate problem that needs to be fixed.

[ausnp84]

Finally got around to changing the fuel filter and lo and behold, success!! Now, it could’ve been a combination of things (lift up, air in the line, etc) and I find it hard to believe it was just the fuel filter, but seems ok for the moment and I’ll have the engineer give it the once over just to be on the safe side.

Boats eh? Who’d have ‘em! Haha

N

[zeseb]

A very good truck diesel mech who is my boat neighbour at my marina, did 2 tests:
1- In case it happens again, put the diesel pipe before the first fuel filter (CAV Filter usually) into a full diesel 20L Jerrycan and start it > The fuel will be pumped by the engine and it will tell you if that's the fuel in the tank which is crap and in that case, polish the fuel (Or get rid of it) and clean the tank
2- With you current situation, go at the near-maximum rpm that your engine can go and see if it can goes high (Read the engine manual to know the theorical max) > If there isn't enough fuel going into the engine, then the engine will stop by itself due to some lack of fuel and in that case, something on the line slows down the fuel flow

I changed many times my fuel filters, it worked 2-10h but back to square one. So, I am not really optimistic. Who knows? I wish you this is only the filters indeed.