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Engine alternator issues.....any suggestions?


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This is a problem I've had with RUNE for quite a while, it just seems to be getting worse at the moment and I'm struggling to find the cause. To run through the sequence of events when starting up:-

1) Turn on ignition key, oil warning light, engine alternator light and domestic alternator light all come on,along with light indicating that the heater coil is operating.

2) Heater coil light goes out and then turn key further which engages starter motor.

3) Engine fires up and all lights go out.

now things get a bit more tricky

4) Tachometer needle goes to about 750 - 800 rpm and freezes at the same time the engine alternator drive belt can be heard slipping.

5) After 2 minutes the sound of the slipping belt stops, the tachometer comes back online and everything is hunky dory.

 

Once the engine has warmed up, if it is switched off the slipping drive belt happens again but only for about 30 seconds or so, similarly if the ignition switch is accidentally turned off whilst the engine is running, without tripping the stop solenoid, and then turned back on the slipping drive belt happens again for about 30 seconds then stops.

 

The drive belt itself is as tight as I would wish it to be having made the mistake in the past of tightening it which stopped the slipping belt for a while, then overloaded the water pump bearing which failed, a more difficult job to change than just changing a drive belt! I carry a spare alternator and several spare drive belts (the drive belt is a multi V)

 

Once the engine has fired up and the slipping belt stops, it doesn't happen again until the engine is stopped, no matter how the engine is revved, or otherwise, which is why I'm content with the belt tensioning. The engine concerned is a Lister LPW4, anyone got any idea what the problem is?

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1 minute ago, Wanderer Vagabond said:

This is a problem I've had with RUNE for quite a while, it just seems to be getting worse at the moment and I'm struggling to find the cause. To run through the sequence of events when starting up:-

1) Turn on ignition key, oil warning light, engine alternator light and domestic alternator light all come on,along with light indicating that the heater coil is operating.

2) Heater coil light goes out and then turn key further which engages starter motor.

3) Engine fires up and all lights go out.

now things get a bit more tricky

4) Tachometer needle goes to about 750 - 800 rpm and freezes at the same time the engine alternator drive belt can be heard slipping.

5) After 2 minutes the sound of the slipping belt stops, the tachometer comes back online and everything is hunky dory.

 

Once the engine has warmed up, if it is switched off the slipping drive belt happens again but only for about 30 seconds or so, similarly if the ignition switch is accidentally turned off whilst the engine is running, without tripping the stop solenoid, and then turned back on the slipping drive belt happens again for about 30 seconds then stops.

 

The drive belt itself is as tight as I would wish it to be having made the mistake in the past of tightening it which stopped the slipping belt for a while, then overloaded the water pump bearing which failed, a more difficult job to change than just changing a drive belt! I carry a spare alternator and several spare drive belts (the drive belt is a multi V)

 

Once the engine has fired up and the slipping belt stops, it doesn't happen again until the engine is stopped, no matter how the engine is revved, or otherwise, which is why I'm content with the belt tensioning. The engine concerned is a Lister LPW4, anyone got any idea what the problem is?

 

What do you mean by 'as tight as you would like it to be'?

 

How much deflection is there on the longest run?

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3 minutes ago, The Happy Nomad said:

 

What do you mean by 'as tight as you would like it to be'?

 

How much deflection is there on the longest run?

Somewhere about 4mm I would guess. Having made the mistake of tightening it beyond this once before and overloading the water pump bearing, I'm reluctant to make the same mistake again. Once the engine is running (after the initial slipping period) the belt doesn't slip any more.

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5 minutes ago, Wanderer Vagabond said:

Somewhere about 4mm I would guess. Having made the mistake of tightening it beyond this once before and overloading the water pump bearing, I'm reluctant to make the same mistake again. Once the engine is running (after the initial slipping period) the belt doesn't slip any more.

 

Have you tried spinning the water pump and the alternator with the belt off. Do they spin freely?

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3 minutes ago, The Happy Nomad said:

 

Have you tried spinning the water pump and the alternator with the belt off. Do they spin freely?

Yes (both of them). The puzzle is that the alternator is obviously putting out charge because the warning light has gone out (I've had alternators fail in the past and the warning light always comes on), it is the tachometer that is the clue, it 'freezes' until the slipping belt stops, then operates normally.

Edited by Wanderer Vagabond
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When was the belt last changed, and were the pulley grooves  cleaned at the same time? Multi rib/poly V belts are very sensitive to rubber build up in  the groove roots- the belt then cannot wedge properly into the vees.  Performance falls off and the belt wears quickly, and slips worse.  It is a vicious circle  leading to poor charging.

 

 At and immediately after start up the alternator is working hardest because it has to replace the charge you just used to start up.  The battery voltage is down after a heavy current discharge but  the alternator wants it to be 14.4 V or so, and goes to full output.  If all is not perfick, the bielt slips.  Not enough to notice at first but it gets worse every time.  The problem is made worse by the speed up nature of the alternator drive.  That makes the alternator pulley the most heavily loaded part of the drive and gives it a poor belt-wrap to carry the load.

 

Since it and the water pump turn freely, I doubt there is much wrong with your alternator and what you have is just  start up overload on the belt.  This is common and some alternators (big beggars) have a soft start to prevent it.

 

The current belt will be past its best if it has been slipping on start for more than a few days. So, if the belt is not brand new, replace it and give both the drive pulley and the alternator pulley grooves a good clean with a wire brush, (or a tooth brush and carb cleaner) making sure you get to the bottom of the grooves and get all he old rubber off. Then tension the new belt in accordance with the Lister instructions.

 

It is also a good idea only to buy top- notch belts.  Gates, Continental, Brammer are good names.  Chinese cheapos are only any good for running a washing machine.

N

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21 minutes ago, BEngo said:

When was the belt last changed, and were the pulley grooves  cleaned at the same time? Multi rib/poly V belts are very sensitive to rubber build up in  the groove roots- the belt then cannot wedge properly into the vees.  Performance falls off and the belt wears quickly, and slips worse.  It is a vicious circle  leading to poor charging.

 

 At and immediately after start up the alternator is working hardest because it has to replace the charge you just used to start up.  The battery voltage is down after a heavy current discharge but  the alternator wants it to be 14.4 V or so, and goes to full output.  If all is not perfick, the bielt slips.  Not enough to notice at first but it gets worse every time.  The problem is made worse by the speed up nature of the alternator drive.  That makes the alternator pulley the most heavily loaded part of the drive and gives it a poor belt-wrap to carry the load.

 

Since it and the water pump turn freely, I doubt there is much wrong with your alternator and what you have is just  start up overload on the belt.  This is common and some alternators (big beggars) have a soft start to prevent it.

 

The current belt will be past its best if it has been slipping on start for more than a few days. So, if the belt is not brand new, replace it and give both the drive pulley and the alternator pulley grooves a good clean with a wire brush, (or a tooth brush and carb cleaner) making sure you get to the bottom of the grooves and get all he old rubber off. Then tension the new belt in accordance with the Lister instructions.

 

It is also a good idea only to buy top- notch belts.  Gates, Continental, Brammer are good names.  Chinese cheapos are only any good for running a washing machine.

N

This sounds like it could be a likely cause, although the belt hasn't just been slipping for a few days, it has been slipping for months, it has just got worse since I came out this year back in July. Previously (like last year) it would slip for about 10 seconds or so on start up and then stop but I had the domestic alternator fail coming through Peterborough last year and had to run on just the engine alternator to charge both banks of batteries until I could get a replacement (with the domestic alternator disconnected and a jump lead across the engine - domestic batteries). That certainly made the drive belt squeal on start up! The spare belts I've got are all Gates so I'll give your suggestion a try.

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If it's a poly V belt as BEngo suggest, then I can only think you need to clean the crankshaft and alternator pulleys. If it's an ordinary V belt you may have an incorrect pulley on the alternator and it could have been like that for years. You may have inadvertently been fitting the wrong profile belt. Get a new belt, twist it inside out and push it into the pulleys. Ensure the sides of the belt are a perfect match to the pulley, with both having the same angle. Ensure the belt sits well above the bottom of the pulley.

 

Do you have any enhanced charging kit like an alternator controller or A to B?

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Been there, done that. Had the same thing on an LPW3 in our previous boat. After much faffing about I concluded that the 4PK belt in combination with a small alternator pulley just didn’t play nicely together for a short while after start up due to the high demand on the alternator. The solution was to fit a slightly larger pulley to the alternator to increase the “wrap” and thereby increase the contact area between the belt and pulley.

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3 minutes ago, Tony Brooks said:

If it's a poly V belt as BEngo suggest, then I can only think you need to clean the crankshaft and alternator pulleys. If it's an ordinary V belt you may have an incorrect pulley on the alternator and it could have been like that for years. You may have inadvertently been fitting the wrong profile belt. Get a new belt, twist it inside out and push it into the pulleys. Ensure the sides of the belt are a perfect match to the pulley, with both having the same angle. Ensure the belt sits well above the bottom of the pulley.

 

Do you have any enhanced charging kit like an alternator controller or A to B?

Its a multi/poly V belt so I'll give BEngo's suggestion a try. What threw me was the fact that although the tachometer is frozen, the alternator warning light remains unlit. When the domestic alternator failed last year I realised because there was no charge registering on the Victron meter and the warning light came on (albeit very dimly, only visible in reduced light) for the current issue with the engine alternator the warning light stays off no matter how dim the lighting.

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5 minutes ago, Eeyore said:

Been there, done that. Had the same thing on an LPW3 in our previous boat. After much faffing about I concluded that the 4PK belt in combination with a small alternator pulley just didn’t play nicely together for a short while after start up due to the high demand on the alternator. The solution was to fit a slightly larger pulley to the alternator to increase the “wrap” and thereby increase the contact area between the belt and pulley.

That also sounds like a good idea since this slipping belt has been an issue for a long time. It was slipping way back in 2016 when I knackered the water pump bearing trying to tighten the belt to stop it slipping. It cost me 4 days in Pyrford Marina to change the water pump. How much bigger was the pulley that you fitted?

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As it's a polly-V belt this does not apply to you, but it is for those using ordinary V belts. The toothed, notched, or  cogged belts with teeth around the inside are made to drive around smaller pulleys so if you change one for a plain belt that then slips or you have a plain V belt that is slipping like this try one of the notched belts.

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If the alternator stopped working I’d expect the tacho to fall to zero. If the alternator was slipping I’d expect the tacho to under-read, but that is not the same as “frozen” ie completely unresponsive to changes in rpm.

 

“Frozen” tacho implies loss of dc electrical power to the tacho so I’d suggest measuring the tacho 12v dc supply with a meter whilst the belt slipping/ tacho freeze is happening.

 

You don’t mention the type of alternator but with a 9 diode one, switching off the ignition once it’s running should have no effect. Since it does have an effect presumably it’s a 6 diode machine?

 

I’m struggling to invent a scenario that explains the behaviour but wondering if it’s something along the lines of a temporary (maybe partial) loss of battery supply to the panel and with that same supply being used as voltage sense. The low sense voltage could be forcing the alternator output to maximum and that maximum load causing the belt slip. So in addition to the above measurement of tacho supply voltage, I’d also measure the alternator output voltage at the B+ alternator terminal whilst the fault is happening.

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6 hours ago, nicknorman said:

If the alternator stopped working I’d expect the tacho to fall to zero. If the alternator was slipping I’d expect the tacho to under-read, but that is not the same as “frozen” ie completely unresponsive to changes in rpm.

 

“Frozen” tacho implies loss of dc electrical power to the tacho so I’d suggest measuring the tacho 12v dc supply with a meter whilst the belt slipping/ tacho freeze is happening.

 

You don’t mention the type of alternator but with a 9 diode one, switching off the ignition once it’s running should have no effect. Since it does have an effect presumably it’s a 6 diode machine?

 

I’m struggling to invent a scenario that explains the behaviour but wondering if it’s something along the lines of a temporary (maybe partial) loss of battery supply to the panel and with that same supply being used as voltage sense. The low sense voltage could be forcing the alternator output to maximum and that maximum load causing the belt slip. So in addition to the above measurement of tacho supply voltage, I’d also measure the alternator output voltage at the B+ alternator terminal whilst the fault is happening.

I must say I'm beginning to wonder whether it may be time to invest in a professional diagnosis of the problem. It has been going on for a long time now and whilst the suggestions so far have all been good, it is the freezing of the tacho that has me baffled. As you say it sounds like a temporary loss of battery supply to the panel since the tacho freeze (and slipping belt) is exactly the same as happens if the ignition switch is turned off with the engine running without activating the stop solenoid, if the stop solenoid is activated the tacho returns to zero. I'm starting to think that this problem may be well above my pay grade, does anyone know of a good electrician? Currently in Stone, Staffs.

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48 minutes ago, nicknorman said:

Ed Shiers, four counties marine. Not far away.

 

once he’s worked out what the problem is, do tell us, it’s intriguing!

Thanks for that, looked him up and he is apparently in Leek, which is where we are heading so I'm going to give him a call.

 

Small correction to my last, the tacho doesn't zero when the ignition is turned off and the stop solenoid is activated, it zeros when the ignition is turned back on again before firing up, not that it solves my problem.

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1 minute ago, Wanderer Vagabond said:

Thanks for that, looked him up and he is apparently in Leek, which is where we are heading so I'm going to give him a call.

 

Small correction to my last, the tacho doesn't zero when the ignition is turned off and the stop solenoid is activated, it zeros when the ignition is turned back on again before firing up, not that it solves my problem.

Presumably it would zero if the stop solenoid was pressed, then the ignition was turned off after the engine stopped, which would be the normal way of doing it. Doing it the way round you say, would be expected to give the results you give.

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20 hours ago, Wanderer Vagabond said:

That also sounds like a good idea since this slipping belt has been an issue for a long time. It was slipping way back in 2016 when I knackered the water pump bearing trying to tighten the belt to stop it slipping. It cost me 4 days in Pyrford Marina to change the water pump. How much bigger was the pulley that you fitted?

I think about 10mm bigger, it was a while ago.

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59 minutes ago, Wanderer Vagabond said:

Thanks for that, looked him up and he is apparently in Leek, which is where we are heading so I'm going to give him a call.

 

Small correction to my last, the tacho doesn't zero when the ignition is turned off and the stop solenoid is activated, it zeros when the ignition is turned back on again before firing up, not that it solves my problem.

Mine does that and always had - for many years.

Beta said it was not unusual (and not to fret) - I could always buy another one... At teast it gives a correct / believable value when the engine runs..

It's "not a good idea" to run the engine at slow tickover speed wneh starting to charge a battery that's somewhat discharged. I have a battery booster box-of-tricks which when engaged at low engine revs made all the belts slip - sooo I switch of off until the engine has warmed up - or run the engine at 1600 rpm for ten minutes or so until the high charge current has reduced.

 

Canal boaty stuff will always be a compromise between cost and having to cobble automotive kit together without the availability of an advanced engine management system. On our boat this latter is me. Not too difficult to have a simple  regime  to do what a vehicle's sysyem woud anyway?

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1 hour ago, Sir Nibble said:

This stinks of belt slip but with a poly vee at that tension? How wide is the belt? Any possibility it has a one way drive pulley letting go?

Belt routing?

Loose pulley nut?

That is essentially how I've been treating it over the years but am now coming round to the thinking that I've been wrong and there must be something else doing it. If it were simply belt slip I would expect it to occur at other times or just have a general low level of slip all the while the engine runs,but that doesn't seem to happen. Once the engine has fired up and the slipping stops, that is it, everything is fine and no matter what you try to do with the engine it doesn't slip again until the ignition is turned off.  Once you do that, either by turning off the ignition without activating the stop solenoid (so essentially turning off then back on again with the engine still running) or by stopping the engine the belt slip happens once again, but only for about 20 - 30 seconds rather than the 2 minutes that it slips when the engine is first fired up.

 

The only potential confounding factor is that the boat was fitted with an Adverc back in 2013 soon after we got it. The domestic alternator (which the Adverc was supposed to be installed for) failed later that year and the replacement, installed by an RCR call-out who told me that for the alternator warranty to be valid he'd have to disconnect the Adverc, which he did (as far as I understand). The Adverc is still there but supposedly de-activated, as far as I am aware it was never connected to the engine alternator, but who knows? Whether that is b*ggering something up I don't know, and don't enough about boat electrics to even try to find out.

 

Since I have over the years replaced the alternator concerned and the drive belts (more than once) I had come to just accept what was a minor slippage (rarely more than 10 or 15 seconds on start up) as a simple inconvenience, but considerably preferable to over-tightening the belt and trashing the water pump bearing again. Now that the slippage has increased to over 2 minutes I am  wondering if it is heading towards some sort of failure. I think I'll take the advice of Nicknorman and make contact with someone who has knowledge of boat electrics and see what he can turn up.

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4 hours ago, Wanderer Vagabond said:

Thanks for that, looked him up and he is apparently in Leek, which is where we are heading so I'm going to give him a call.

 

Small correction to my last, the tacho doesn't zero when the ignition is turned off and the stop solenoid is activated, it zeros when the ignition is turned back on again before firing up, not that it solves my problem.

 

This is sort of normal, many tachos work on a sort of servo system rather than a "force against a return spring" like a typical meter.

So, if you turn the ignition off the Tacho loses its power and the needle sticks at its current position. When you turn the ignition back on the tacho has power so drops to zero as it should.   When you operate the stop solenoid I assume the ign is still on so the tacho should drop to zero.

 

The Adverc is not likely to be the problem but just pull the plug out from it to make sure its disabled.

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29 minutes ago, Wanderer Vagabond said:

That is essentially how I've been treating it over the years but am now coming round to the thinking that I've been wrong and there must be something else doing it. If it were simply belt slip I would expect it to occur at other times or just have a general low level of slip all the while the engine runs,but that doesn't seem to happen. Once the engine has fired up and the slipping stops, that is it, everything is fine and no matter what you try to do with the engine it doesn't slip again until the ignition is turned off.  Once you do that, either by turning off the ignition without activating the stop solenoid (so essentially turning off then back on again with the engine still running) or by stopping the engine the belt slip happens once again, but only for about 20 - 30 seconds rather than the 2 minutes that it slips when the engine is first fired up.

 

The only potential confounding factor is that the boat was fitted with an Adverc back in 2013 soon after we got it. The domestic alternator (which the Adverc was supposed to be installed for) failed later that year and the replacement, installed by an RCR call-out who told me that for the alternator warranty to be valid he'd have to disconnect the Adverc, which he did (as far as I understand). The Adverc is still there but supposedly de-activated, as far as I am aware it was never connected to the engine alternator, but who knows? Whether that is b*ggering something up I don't know, and don't enough about boat electrics to even try to find out.

 

Since I have over the years replaced the alternator concerned and the drive belts (more than once) I had come to just accept what was a minor slippage (rarely more than 10 or 15 seconds on start up) as a simple inconvenience, but considerably preferable to over-tightening the belt and trashing the water pump bearing again. Now that the slippage has increased to over 2 minutes I am  wondering if it is heading towards some sort of failure. I think I'll take the advice of Nicknorman and make contact with someone who has knowledge of boat electrics and see what he can turn up.

I don't have the instructions for the Adverc but it suggests to me that turning the ignition off, whether the engine is left running or stopped with the stop solenoid, is resetting the Adverc to maximum charge output from the alternator, hence the belt slip.  It must still be connected, try pulling its plug out.

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I think the tachometer is a red herring. When you switch the ignition off/on you will most likely operate the glow plugs if they are on a timer relay rather than a heat position on  the ignition switch. Putting a load of maybe 70A on the alternator. 

I hasd a similar issue with my engine chewing alternator belts/slipping at start up. Eventually I did as suggested earlier in this thread and properly cleaned all the groves in the crank, water pump and alternator pulleys. Surprisingly large amounts of crud had built up.... the other thing I did was check the alternator alignment. Mine was just out a little bit and I think I moved a washer or something. I've had no problem since and I nolonger see rubber dust from the belt near the water pump pulley. I change my belt annually but they seem to be in much better condition when I take them off.

 

Also  4PK multigroove belt but just a 70A 127 alternator. 

 

Hope that helps a bit 

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