Starting woes (help!)

[MtB]

11 minutes ago, Lochnevis said:

It looks like there is definitely something up with either the alternator or some related piece of wiring, as the charging voltage from the alternator was still very low (12.6V, not the 12.7V I said above).

 

Where are you measuring this charging voltage? On the battery terminals or on the alternator output terminals? It would be helpful and informative to measure in both locations and post up the two voltages.

 

A further point I discovered yesterdays is a brand new battery with a rested terminal voltage of 12.7 is not fully charged. I fitted a new pair of 110ah domestics yesterday to my boat expecting them to be fully charged but no. I fired up the engine and they drew 16A immediately at 14.4v, and an hour later (at 8pm) the tail current was still 10A. This is not in accordance with forum wisdom and I was gonna start t a thread about it... 

[Lochnevis]

3 minutes ago, Mike the Boilerman said:

 

Where are you measuring this charging voltage? On the battery terminals or on the alternator output terminals? It would be helpful and informative to measure in both locations and post up the two voltages.

 

A further point I discovered yesterdays is a brand new battery with a rested terminal voltage of 12.7 is not fully charged. I fitted a new pair of 110ah domestics yesterday to my boat expecting them to be fully charged but no. I fired up the engine and they drew 16A immediately at 14.4v, and an hour later (at 8pm) the tail current was still 10A. This is not in accordance with forum wisdom and I was gonna start t a thread about it... 

At the battery terminals.  I'll post the voltage direct from the alternator tomorrow (if I can start the engine!).

[Tony Brooks]

Has anyone mentioned  the glowplugs yet? If not I would first make sure there is a good 12V at the connection with the key/push button in the glow position and if so measure the current in the supply line. If no high current ammeter (%0 amps plus) take them out and test them across a battery.

[Lochnevis]

12 minutes ago, Tony Brooks said:

Has anyone mentioned  the glowplugs yet? If not I would first make sure there is a good 12V at the connection with the key/push button in the glow position and if so measure the current in the supply line. If no high current ammeter (%0 amps plus) take them out and test them across a battery.

@Boater Sam mentioned them, but I haven't checked them out.  I'll make it the first thing I look at tomorrow.

 

Is %0 amps a typo for 50 amps?

 

What strikes me as odd if how suddenly this problem came on - it was starting fine, I didn't move the boat for 2 days, then it was very hard to start (blowing the 150A fuse I mentioned, and taking several attempts).  And it's been like that ever since.  The weather didn't change much in the 2 days I didn't move the boat, so I guess something else did...

Edited September 28, 2018 by Lochnevis
To ask Tony to clarify a typo

[MtB]

1 minute ago, Lochnevis said:

 

What strikes me as odd if how suddenly this problem came on - it was starting fine, I didn't move the boat for 2 days, then it was very hard to start (blowing the 150A fuse I mentioned, and taking several attempts).  And it's been like that ever since.  The weather didn't change much in the 2 days I didn't move the boat, so I guess something else did...

 

150A strikes me as a very low rather fuse rating for a starter. I'd have thought 300A was more appropriate. 

 

Not that it is common practice to have one at all. 

 

 

[Lochnevis]

11 minutes ago, Mike the Boilerman said:

 

150A strikes me as a very low rather fuse rating for a starter. I'd have thought 300A was more appropriate. 

 

Not that it is common practice to have one at all. 

 

 

It was one of these, a Bussmann MRBF-150 (I hope the picture works - my first attempt at posting a picture here).  I fitted it when rewiring my domestic system prior to boat safety.  I had intended to fuse only the domestic battery, but I ended up with two of them when I stuffed up an order, so tried it out on the starter, and it worked (to my surprise - I'd assumed I'd need a larger fuse); then it worked for over a year, including the winter months.

 

I've just looked at the datasheet, and it's interrupt time at 200% is 60 seconds, which may be why it was working.

Edited September 28, 2018 by Lochnevis
spelling, and to name the type of fuse

[Dr Bob]

2 hours ago, Lochnevis said:

Update: I went and bought a new starter battery this morning (same size as before, a 644).  The starter battery was definitely knackered, but it seems that there's an underlying problem.  I'm now back to where I was a couple of weeks ago - it takes several attempts to start: four times cranking ~30 seconds.  After a while (on the 4th attempt, for most of the time) the engine sounds like it's about to fire, but keeps not quite managing it.  I couldn't swear that the starter is turning over as fast as it used to, but it doesn't sound unusually slow or otherwise wrong (and it's turning over much faster than it was yesterday, with the old battery).

 

It looks like there is definitely something up with either the alternator or some related piece of wiring, as the charging voltage from the alternator was still very low (12.6V, not the 12.7V I said above).  Unfortunately I didn't have time to move the boat today (so I've left the starter hooked up to the solar charger+domestics to make sure it gets a proper recharge.

 

Everyone is focussing on the electrics (apart from Tony on the glow plugs).

When we bought our boat there was a problem starting it...exactly what you said. During the survey a few days before it was perfect ....as it was when we first saw the boat. We tried everything as it felt like an 'air in the fuel' problem. Filters, joint tightness etc, fuel being delivered etc. It would start if you cranked it long enough (Beta 43). In the end we gave up. Called in RCR. He did everything again but still no problem....but then noticed the problem. The female union on the end of the pipe from the diesel tank was cracked, so as you tightened it on the first fuel filter, the crack opened up ....hence letting air in. As the union was turned so the crack was downwards, you couldnt see it. Replace the union (and hose) and sorted! Well done RCR!

When you said you thought it was spinning just as fast as before on starting, it points me back to looking at fuel issues. Check all you unions again! Best of luck.

[Lochnevis]

35 minutes ago, Dr Bob said:

Everyone is focussing on the electrics (apart from Tony on the glow plugs).

When we bought our boat there was a problem starting it...exactly what you said. During the survey a few days before it was perfect ....as it was when we first saw the boat. We tried everything as it felt like an 'air in the fuel' problem. Filters, joint tightness etc, fuel being delivered etc. It would start if you cranked it long enough (Beta 43). In the end we gave up. Called in RCR. He did everything again but still no problem....but then noticed the problem. The female union on the end of the pipe from the diesel tank was cracked, so as you tightened it on the first fuel filter, the crack opened up ....hence letting air in. As the union was turned so the crack was downwards, you couldnt see it. Replace the union (and hose) and sorted! Well done RCR!

When you said you thought it was spinning just as fast as before on starting, it points me back to looking at fuel issues. Check all you unions again! Best of luck.

Thanks Dr Bob.  The symptoms sound remarkably similar, and I had a new fuel tank fitted in the spring, so maybe one of the new connections is dodgy.  It would never have occurred to me that a cracked hose/union could result in a starting problem, but then the engine running fine, so I haven't looked nearly as hard as I would have if I wasn't sure that fuel was getting to the engine.  I will now!

[Tony Brooks]

3 hours ago, Lochnevis said:

@Boater Sam mentioned them, but I haven't checked them out.  I'll make it the first thing I look at tomorrow.

 

Is %0 amps a typo for 50 amps?

 

What strikes me as odd if how suddenly this problem came on - it was starting fine, I didn't move the boat for 2 days, then it was very hard to start (blowing the 150A fuse I mentioned, and taking several attempts).  And it's been like that ever since.  The weather didn't change much in the 2 days I didn't move the boat, so I guess something else did...

Yes, 50 amps +

 

This could all be tied in with the faulty batteries. Glow plugs use a positive temperature coefficient filament so the resistance rises in proportion to temperature. I the battery voltage is low the heating effect will be low so the resistance will   below allowing more current to flow for longer. This could be enough to cause problems in the glow plug part of the main harness multi-plug or other connection. This is only a theory.

 

I think fusing the starter battery is not best practice. Yes, fuse the feed to the ignition switch but NOT the starter motor. In any case I think 150A fuse or a diesel starter is asking for problems. Each connection cause a tiny bit of voltdrop so you have four extra lots of voltdrop. Probably not enough to notice with a good battery but in marginal cases it might make the difference between start or not.

 

I expect your starter is a four brush motor and if one brush makes poor contact you will get reduced starting power but as you say the cranking speed is much the same as before the problem I doubt its that.

 

Look at the exhaust whilst cranking. If its making clouds of white "smoke" almost at once then you have fuel so Dr B's idea is less likely. If it is not or only makes a few wisps of smoke then its likely a fuel problem.

 

Now you have got the cranking speed back this needs logical investigation. I would suggest:

 

1. Look at the exhaust smoke and decide it its fuel system based (if yes report back).

2. Check the glow plugs are all working., even if it does mean taking them all out.

3. Check the valve clearances in case one or more have tightened and thereby causing a loss of compression.

 

Hopefully that will give a clue as to what is wrong.

 

If you want a quick & dirty check of the glow plugs take the air cleaner off and direct a blowlamp into the inlet manifold while cranking. If starting improves then there is a fair chance you have    some failed glow plugs.

 

 

[MtB]

13 minutes ago, Tony Brooks said:

I the battery voltage is low the heating effect will be low so the resistance will   below allowing more current to flow for longer.

 

Surely it will be less current for longer. 

 

With a supply voltage a little lower from a dying battery, the current will be lower according to that nice Mr Ohm, and as power is volts x current, the plugs will heat up possibly quite lot less and quite possibly fail to ignite the fuel. But as the engine fails to start, the user keeps on turning it over for longer leading to the battery getting one helluva beating and the problem multiplies up.

 

[Tony Brooks]

3 minutes ago, Mike the Boilerman said:

 

Surely it will be less current for longer. 

 

With a supply voltage a little lower from a dying battery, the current will be lower according to that nice Mr Ohm, and as power is volts x current, the plugs will heat up possibly quite lot less and quite possibly fail to ignite the fuel. But as the engine fails to start, the user keeps on turning it over for longer leading to the battery getting one helluva beating and the problem multiplies up.

 

If the plug tips are cooler the resistance will be lower but how much this is countered by a low battery voltage I don't know. What I say is still compatible with Ohms law but we don't know the actual relationship between resistance and temperature except the resistance will go up (and limit the current) as the temperature increases.

[ditchcrawler]

24 minutes ago, Mike the Boilerman said:

 

Surely it will be less current for longer. 

 

With a supply voltage a little lower from a dying battery, the current will be lower according to that nice Mr Ohm, and as power is volts x current, the plugs will heat up possibly quite lot less and quite possibly fail to ignite the fuel. But as the engine fails to start, the user keeps on turning it over for longer leading to the battery getting one helluva beating and the problem multiplies up.

 

That assumes the resistance is constant

[Lochnevis]

1 hour ago, Tony Brooks said:

Yes, 50 amps +

 

This could all be tied in with the faulty batteries. Glow plugs use a positive temperature coefficient filament so the resistance rises in proportion to temperature. I the battery voltage is low the heating effect will be low so the resistance will   below allowing more current to flow for longer. This could be enough to cause problems in the glow plug part of the main harness multi-plug or other connection. This is only a theory.

 

I think fusing the starter battery is not best practice. Yes, fuse the feed to the ignition switch but NOT the starter motor. In any case I think 150A fuse or a diesel starter is asking for problems. Each connection cause a tiny bit of voltdrop so you have four extra lots of voltdrop. Probably not enough to notice with a good battery but in marginal cases it might make the difference between start or not.

 

I expect your starter is a four brush motor and if one brush makes poor contact you will get reduced starting power but as you say the cranking speed is much the same as before the problem I doubt its that.

 

Look at the exhaust whilst cranking. If its making clouds of white "smoke" almost at once then you have fuel so Dr B's idea is less likely. If it is not or only makes a few wisps of smoke then its likely a fuel problem.

 

Now you have got the cranking speed back this needs logical investigation. I would suggest:

 

1. Look at the exhaust smoke and decide it its fuel system based (if yes report back).

2. Check the glow plugs are all working., even if it does mean taking them all out.

3. Check the valve clearances in case one or more have tightened and thereby causing a loss of compression.

 

Hopefully that will give a clue as to what is wrong.

 

If you want a quick & dirty check of the glow plugs take the air cleaner off and direct a blowlamp into the inlet manifold while cranking. If starting improves then there is a fair chance you have    some failed glow plugs.

 

 

Plenty of fuel is definitely getting into the engine - clouds of diesel come out of the exhaust (very much "smoke" with inverted commas, as you put it - I can taste the diesel), though it does sound like Dr. Bob's engine was getting fuel too (he says that he checked "fuel being delivered").  I guess I'll give the fuel system a thorough check first (especially the new connections), as that should be fairly quick and easy - then I'll tackle the heater plugs (I don't expect removing them to be either quick or easy!).  I have no idea how to go about checking valve clearances - any pointers/useful YouTube videos anyone could direct me to (I have a copy of the workshop manual somewhere) - or should I get in someone who knows what they're doing at that point?

[roland elsdon]

Please dont verbally slap me. You have checked the engine stop cable havent you.

i say this because i once had a solid cable kink internaly, the push to run ( pull to stop ) lever was pushed but it failed to push the lever on the pump, so no start. 

[Lochnevis]

1 minute ago, roland elsdon said:

Please dont verbally slap me. You have checked the engine stop cable havent you.

 i say this because i once had a solid cable kink internaly, the push to run ( pull to stop ) lever was pushed but it failed to push the lever on the pump, so no start. 

Don't worry - no verbal slapping: been there, done that...  Hand-hauling out of a Thames lock for 30 minutes of troubleshooting (with the lock keeper looking on), to eventually realise that my crew hadn't pushed the toggle back in, and I hadn't thought to check it, was a little embarrassing.  [Forewarned by that experience, I checked the lever on the engine itself, in case of cable snags, as you suggest].

[Tony Brooks]

If the stop control was in the stop position there would be no fuel delivered to the engine. If it was in a mid way position it would still get some fuel and I would except it to start but not rev beyond a certain speed.

 

Checking the valve clearance is simple enough. You will need to know the correct clearance and a feeler gauge set to suit.

First remove the rocker cover.

1. Turn engine over by hand until one valve is fully down.

2. Put a chalk witness mark on the bottom  engine pulley (crankshaft pulley and on a fixed part of the engine.

3. Turn engine over one complete turn (360 degrees) so the two marks line up again - near enough will do.

4. Put feeler gauges into gap between rocker and valve stem head to measure gap. However if there is some gap you can feel by rocking the rocker that will do in this case.

5. Rub chalk mark off pulley and go to one above with a different valve.

 

When you are sure all 8 valves have clearance its done.

 

If you have the amount of fuel you say you have at the exhaust (you can taste it!) and the glow plugs are OK I fear it will either be injection pump timing but that is not very likely on a modern engine or loss of compression.

2 hours ago, ditchcrawler said:

That assumes the resistance is constant

Which it very much is not, if it was the element would melt.

[Boater Sam]

Its possible that the preheater plugs are not working and that there is so much fuel in the cylinders that the compression is having difficulty in getting it hot enough for combustion.

Check if the plugs are getting power in the preheat position by putting a test bulb between one of them and the engine block.

If so it could be possible that they have all burnt out over time till there is none working.

[WotEver]

Just read the thread from start to finish and my first thought remains the main suspect in my opinion, same as Sam & Tony - glow plugs. As Sam suggests above, they may have been failing one by one and now that the last one has died there’s no preheat at all. 

[MtB]

12 hours ago, Boater Sam said:

Its possible that the preheater plugs are not working and that there is so much fuel in the cylinders that the compression is having difficulty in getting it hot enough for combustion.

Check if the plugs are getting power in the preheat position by putting a test bulb between one of them and the engine block.

If so it could be possible that they have all burnt out over time till there is none working.

 

Or use a DC clamp meter on the wires feeding them to detect the current.  Clamp meters are amazingly useful to have around. 

 

[Tony Brooks]

1 hour ago, Mike the Boilerman said:

 

Or use a DC clamp meter on the wires feeding them to detect the current.  Clamp meters are amazingly useful to have around. 

 

Probably the best method. For four plugs expect maybe 100 amps at first and quickly dropping to about 50 amps as they warm up. So anything less than around 50 amps after about 10 seconds will indicate one or more plug failures (Very general figure, check manual for exact  data).

 

Nothing to do with this topic but the equivalent figures for a BMC 1.5 are about a steady 6 amps per plug but now some start much higher and drop

[Lochnevis]

I've taken out the heater plugs and tested them across a battery - and three of them seem to be dead.  So hopefully I've finally gotten to the bottom of the problem, with lots of help from the forum!

 

I've ordered replacements, and I'll report back once they're fitted.  In the meantime, I'll get myself a feeler gauge to check the valve clearance, and enjoy the fact that there are many worse places to be broken down than the water meadow in Abingdon, especially in this weather!

 

Then I may well be back with questions about how to troubleshoot my alternator, assuming the low charging voltage doesn't turn out to be a wiring issue, and if forum searches come up blank.

 

Thanks all for the help and friendly advice; I'd have been utterly baffled without you.  I will investigate if I've posted enough or whatever to sprinkle some greenies around.

[Scholar Gypsy]

If you want to test your compression it's easy to do once the glow plugs are out. Here's a recent thread. I get 460 psi on my K4E, now it has been rebuilt.  I had some quite similar symptoms to you...

 

 

[Tony Brooks]

On 29/09/2018 at 15:09, Lochnevis said:

I've taken out the heater plugs and tested them across a battery - and three of them seem to be dead.  So hopefully I've finally gotten to the bottom of the problem, with lots of help from the forum!

 

I've ordered replacements, and I'll report back once they're fitted.  In the meantime, I'll get myself a feeler gauge to check the valve clearance, and enjoy the fact that there are many worse places to be broken down than the water meadow in Abingdon, especially in this weather!

 

Then I may well be back with questions about how to troubleshoot my alternator, assuming the low charging voltage doesn't turn out to be a wiring issue, and if forum searches come up blank.

 

Thanks all for the help and friendly advice; I'd have been utterly baffled without you.  I will investigate if I've posted enough or whatever to sprinkle some greenies around.

 

A the more discharged the battery is the higher the charging current and the lower the charging voltage so although 12.7 seem low to me it is not a definite indication of a faulty alternator.

 

My advice would be to start the engine and put a jump lead between the engine and domestic battery positives (take it off as soon as you stop for the day). That way the domestic alternator will charge both batteries. At the end of a good days cruise lasting four hours or preferably longer remove the jump lead and then measure the charging voltage and report back. I would expect it to be in the high 13.xxs and hopefully 14.2V plus. If its still around 13V or below I fear its new alternator time.

 

[philjw]

On 28/09/2018 at 19:20, Tony Brooks said:

1. Turn engine over by hand until one valve is fully down.

This will be a lot easier if you do it before replacing the glow plugs but you probably won't need to check the valve clearances as the glow plugs are the likely culprits. Still it is a reasonable piece of preventive maintenance.

[Tony Brooks]

1 hour ago, philjw said:

This will be a lot easier if you do it before replacing the glow plugs but you probably won't need to check the valve clearances as the glow plugs are the likely culprits. Still it is a reasonable piece of preventive maintenance.

Personally I don't like checking things on in case unless the symptoms call for it and they don't in this case unless it still has starting pr5oblms..It gives a chance for things to go wrong like gasket leaks. Not that a Mitsubishi rocker cover should leak with its rubber seal.

 

I agree, try starting it and see how it goes.