BMC not starting

[StarUKKiwi]

We have a BMC engine, yesterday, we ran the engine whilst moored and the engine did race a bit. Today, she is turning, in fact, she did start but cut out straight away; now she is turning over, but not starting - clues as to what it is? (edited to add detail)

Edited May 25, 2014 by StarUKKiwi

[Alan de Enfield]

Whenever a diesel engine wont start and is turning over I always look to the fuel supply first;

 

Is there fuel in the tank ? (enough - not just a couple of inches)

Is fuel getting to the inlet side of the filter ?(crack the supply nut open a bit)

Is fuel exiting the filter ?(crack the outlet side nut a bit)

Is fuel getting to the pump ?

Is it getting to the injectors ?

 

You can start at either end of the system - if starting with the injectors just crack the nut open a little and see if you are getting any fuel or air bubbles.

[StarUKKiwi]

Sorry,Alan, I'm a bit of a novice - do you mean bleed it?

That was quick though, thanks - there was still quarter full and Nb Alton called today, so we filled up. I wondered if it was an air bubble?

[Alan de Enfield]

Yes - just ensure you are getting diesel to the injectors - if not then bleed the system.

 

If you are then its something else, but diesels are basically very simple - if you have fuel, air and compression (arriving at the correct time) then it should run.

 

It could be that 'filling up' has stirred the muck up in the bottom of the tank, which has now reached and blocked the filter - the engine ran for a short while whilst it used the fuel in the pipe but then 'ran out of fuel' as no more was coming from the filter.

Edited May 25, 2014 by Alan de Enfield

[StarUKKiwi]

Ok, that makes sense, I am unsure (an engine still looks a bit like a jigsaw puzzle to my untrained eye) of where I should be loosening?

[Alan de Enfield]

Try and find out if the filter is blocked / clogged.

 

Find the fuel filter - follow the copper fuel pipes from your tank - the filter is (normally) a 100mm diameter metal cylinder about 150mm long It will have a copper pipe going 'in' on one side and a similar pipe on the 'out' side. There may be arrows cast into the top of he filter to show you the fuel flow direction.

 

There should / may be a nut in the centre of the top of the filter, loosen this (no need to remove it, as if fuel comes out you need to screw it back in quickly) and see if fuel bubbles out

 

Yes - OK

No - Filter is probably clogged up

 

If fuel is flowing, then tighten it back up and loosen the nut holding the copper pipe on the OUTLET side, again do not remove it completely, is fuel flowing ?

 

Yes - problem is futher down the line.

No - Fuel filter blocked.

 

Do you have a spare filter on board ?

Do you know how to change a fuel filter ?

[b0atman]

First are you getting smoke out of exhaust

Yes then ignition of fuel problem Glow plugs.

No then look for why no fuel check stop button out and shut off valve open.

Then start deeper investigation as above.

[StarUKKiwi]

Right, we followed all the instructions and we had air in the system. We think.it's because the fuel.inlet pipe was above the level of the fuel in the tank and so.it was letting air in, so although we had quarter of a tank left, it was above the level.of the diesel - so we have made a note on the dip stick - thanks all, still learning after nine months aboard!

Try and find out if the filter is blocked / clogged.

 

Find the fuel filter - follow the copper fuel pipes from your tank - the filter is (normally) a 100mm diameter metal cylinder about 150mm long It will have a copper pipe going 'in' on one side and a similar pipe on the 'out' side. There may be arrows cast into the top of he filter to show you the fuel flow direction.

 

There should / may be a nut in the centre of the top of the filter, loosen this (no need to remove it, as if fuel comes out you need to screw it back in quickly) and see if fuel bubbles out

 

Yes - OK

No - Filter is probably clogged up

 

If fuel is flowing, then tighten it back up and loosen the nut holding the copper pipe on the OUTLET side, again do not remove it completely, is fuel flowing ?

 

Yes - problem is futher down the line.

No - Fuel filter blocked.

 

Do you have a spare filter on board ?

Do you know how to change a fuel filter ?

Just realised though, we have no spare and no I don't - i need a mechanical course, I could change a fuel filter in a motorbike, 30 years ago! So, still need to learn that

[Alan de Enfield]

Well done "all sorted"

 

A fresh delivery can occasionally cause problems, particularly if your fuel level is low and there is muck in the bottom of the tank. Always worth having one, or even two filters hidden away somewhere.

 

It is surprising how high in the tank some of the pick-up pipes are buts its good that you now know how high your is.

 

Changing the filter is very simple (and not messy like an oil filter), just ask another boater one day (it'll only take a few seconds to show you), and now you know how to bleed the system thats the hard part sorted.