Safely onto a mooring but engine problem

[FairweatherDave]

Started the engine but noticed quickly it was revving only up to 3000. Beta 25/20. Managed to motor slowly max 4 knots for 3 hours. Then the revs dropped and the engine petered out. Sailed on to a mooring and I have changed primary and secondary filter. To me the fuel looked fine. Can restart the engine but any revs and it dies. Doesn't sound great even at tickover. Any pointers really appreciated. I can give more thoughts but don't want to lead with suggestions yet. Plenty of water flow and exhaust looks normal.

 

[FairweatherDave]

Meanwhile Fray bentos time to get in a better mood .

 

[earlybird]

Get it running and carefully slacken off each of the 3 injector lines in turn. If one of them makes no difference there's a problem with that injector/cylinder.
Otherwise might be the lift pump in which case try a day tank with gravity feed.
'Phone Beta on Tuesday!

 

[PetiteFleur]

It sounds like air leaking into the fuel system somewhere - I had this after fitting a new engine, spoke to the local Beta agent and he said 'tighten all the unions on the fuel system' Cured the problem but never found out which union was 'leaking air'.

 

[FairweatherDave]

Thanks early bird. I will try those tomorrow. I like the idea of the lift pump . Pie and beer help. Hoping for enough wind to sail away and sort later . Bit wary of touching the injectors.

 

[FairweatherDave]

It sounds like air leaking into the fuel system somewhere - I had this after fitting a new engine, spoke to the local Beta agent and he said 'tighten all the unions on the fuel system' Cured the problem but never found out which union was 'leaking air'.

That's interesting. I thought an air leak in..... but I have not touched anything on the fuel side. I felt it was a slow motion failure, unlike a sudden fuel block. I just changed the filters cos overdue...

 

[Sandy]

Any crud in the primary filter?

When was the last time you cleaned the fuel lines/tank?

 

[Biggles Wader]

I had bug in the tank which formed a clot where the fuel line leaves the tank. There was no evidence of it in either filter but the engine would fire up then stop straight away. Try taking the fuel lines off and blowing back through them. I eventually drained the tank and found a fair bit of crud in the dregs. I also now carry a spare can of fuel and a length of fuel pipe so I can rig a jury tank in case of emergency.

 

[FairweatherDave]

Any crud in the primary filter?

When was the last time you cleaned the fuel lines/tank?

Filter seemed crud free to me.
Was already thinking fuel line from tank to filter could be blocked....how do you unblock?

 

[RichardS]

An easy thing would be to release the diesel filler cap and just check that there is no vacuum building up.

Second easy check would be to check the exhaust elbow for any restriction.

After those two, I would start on bleeding fuel lines etc as others have said.

Richrad

 

[pcatterall]

Similar symptons when there is water in a filter. We had water in an opaque sedimeter the engine ran at slow revs but as soon as they were increased water was drawn up and stopped the engine.
The OP has changed filters so would normally have spotted this but worth a mention.

 

[FairweatherDave]

Were we not rolling about on an exposed spot I might be having a go. Troop morale not hi.....night! Thanks for the further thoughts

 

[Yellow Ballad]

I have a cotton rade covered rubber line from the cav filter and it had started to split with age. It was just enough to allow a small amound of air to be drawn in.

 

[Neeves]

Looking at the easy options - I'd check the exhaust elbow first, as mentioned by Richard. Undo the bolts and look - easy.

How many hours has the elbow done? - think 1,000 hours for issues. Everything looks 'normal' until you check the interior of the elbow (looking from the engine side).

Sadly there is no instant remedy - you can acid wash, the build up is calcium carbonate (though it looks like carbon) which will dissolve in acid (which carbon would not) but its a messy business (and does not always work - the acid will attack rust and eventually the elbow itself). You might be able to ream it out - I've never tried.

Acid - anything a brickie would use - plastic bucket, heavy duty rubber gloves, on shore, outdoors - keep children, wives and pets well away, soak overnight. The fume are pretty aggressive

If the elbow is good - follow other options, above.

Jonathan

 

[Aeolus]

Air filter badly in need of replacement?

 

[KellysEye]

One thing it could be is an air leak that lets diesel out, wrap kitchen roll around all joints, the bleed screw and joints in fuel filters. Start the engine and check for diesel in the kitchen roll.

 

[Praxinoscope]

It sounds like air leaking into the fuel system somewhere - I had this after fitting a new engine, spoke to the local Beta agent and he said 'tighten all the unions on the fuel system' Cured the problem but never found out which union was 'leaking air'.

Had a similar problem on my Beta engine, and taking off the crimped hose clips on the fuel lines, and replacing them with Jubilee clips cured the problem so I assume it was air entering the fuel system.

 

[RichardS]

Air filter badly in need of replacement?

That's an interesting suggestion. I've seen air filters from cars which have spent their lives on dirt tracks in Africa and one could say that after a few years the paper filter is looking rather the worse for wear but I wonder whether an air filter/mesh on a boat would ever need to be replaced?

Richard

 

[Appledore]

A couple of seasons ago I found my 1GM 10 wouldn't achieve max revs. It was OK at low revs, but on increasing the throttle position it didn't pick up, and then the engine started to die, and only continued to run when I reduced revs. When I removed the Vetus fuel tank I found a lot of crud in there, including what a friend calls 'millstone grit' particles. I can only assume that with the increase in revs, a particle of crud was sucked onto the bottom of the fuel intake pipe, only to fall away when the revs were reduced. I have since installed a larger primary filter, but this would not have prevented the symptons described.

 

[lw395]

Started the engine but noticed quickly it was revving only up to 3000. Beta 25/20. Managed to motor slowly max 4 knots for 3 hours. Then the revs dropped and the engine petered out. Sailed on to a mooring and I have changed primary and secondary filter. To me the fuel looked fine. Can restart the engine but any revs and it dies. Doesn't sound great even at tickover. Any pointers really appreciated. I can give more thoughts but don't want to lead with suggestions yet. Plenty of water flow and exhaust looks normal.

If you've just changed the filters, there may be air in the system which can take a few minutes running at speed/load to work itself out.

The acid test of the fuel supply system, is 'does it maintain a positive pressure of fuel at the inlet to the injector pump?'
If you have a suitable gauge and T-piece, you can check that directly.

Likewise, a vacuum gauge before the lift pump tests everything upstream of it.

Sometimes you can crank the engine with the pipe which supplies the injector disconnected and directed into a jam jar. Cranking decompressed at 400rpm for 30 seconds, a normal healthy system will be delivering enough l/hr to run flat out.
Doesn't work with engines that return more diesel to the tank than they burn.

If all else fails, try running from a known good clean can of fuel. If it runs good with the can raised but not lowered, look at the lift pump.
If it runs well both raised and lowered, suspect the tank line is blocked?

Odd possibilites include blocked air filter or blocked exhaust.
I know a tale about someone 'losing' a rag in the exhaust when they 'winterised' the engine, with amusing consequences next season.