Jump to content

Diagnosis of an odd starting problem


frahkn

Featured Posts

I wonder if someone could help identify a starting problem?

 

I need to focus on a single issue, so if you could limit your diagnostic thinking within the limited information supplied, that would be a particular help to me.

 

Sometimes my engine won’t start, i.e. it does not turn over and there is a “click” very like a solenoid click but nothing else.

 

If I turn the belt pulley a little it then starts as normal.

 

There is no pattern to its starting/not starting but this season, out of 98 attempts it has failed to start 15 times. Only two non starts were on consecutive days, the longest period of successful starts was 17 days.

 

How much I need to move the pulley varies, usually only once but occasionally several times.

 

Can anyone say what particular fault could produce these results?

 

The engine is a Beta 43 and it is in an engine room so this is not an enormous problem, but it is irritating.

Link to comment
Share on other sites

If the engine had been a marinised petrol engine I would say it would very likely be the starter bendix stuck in mesh, especially if you got a bit of a click as you moved the pulley, but it is not and diesels use a different form of starter drive.

 

How old/how many hours is on the engine because a four-cylinder diesel will stop in only one of two positions and if the teeth on the flywheel in that area and/or on the starter pinion are burred then the moving gear on the starter motor can hit the burr and that will stop the contacts that apply power to the actual motor from closing. Hence, the click as the solenoid tries to pull the gears into mesh but nothing else. Move the engine round, so undamaged teeth are then in line, and it will engage the gears properly and start.

 

Unfortunately it is unlikely to be easy to get the starter motor off a Beta, so you can inspect the flywheel teeth, but if you can and find burs you can file the burs until the tooth shape is similar to the undamaged ones.

 

There may be other causes, especially if you use a relay or another solenoid to energize the relevant terminal on the motor, but that is not typical Beta practice.

 

 

Link to comment
Share on other sites

Agree with Tony on the mechanical non engagement of the pinion.

 

But check all the electrical connections from battery through to starter and the negative returns from engine to battery. You could just have a high resistance connection.

Link to comment
Share on other sites

2 minutes ago, Tony Brooks said:

If the engine had been a marinised petrol engine I would say it would very likely be the starter bendix stuck in mesh, especially if you got a bit of a click as you moved the pulley, but it is not and diesels use a different form of starter drive.

 

How old/how many hours is on the engine because a four-cylinder diesel will stop in only one of two positions and if the teeth on the flywheel in that area and/or on the starter pinion are burred then the moving gear on the starter motor can hit the burr and that will stop the contacts that apply power to the actual motor from closing. Hence, the click as the solenoid tries to pull the gears into mesh but nothing else. Move the engine round, so undamaged teeth are then in line, and it will engage the gears properly and start.

 

Unfortunately it is unlikely to be easy to get the starter motor off a Beta, so you can inspect the flywheel teeth, but if you can and find burs you can file the burs until the tooth shape is similar to the undamaged ones.

 

There may be other causes, especially if you use a relay or another solenoid to energize the relevant terminal on the motor, but that is not typical Beta practice.

 

 

Thanks very much Tony.

 

First your question; the engine is 19 years old and has nearly 13,000 hours on the clock.

 

The click is when I turn the key, not when I move the pulley.

 

On small movement usually solves the problem but occasionally I have to move it several times, almost a full rotation.

Link to comment
Share on other sites

1 minute ago, Tracy D'arth said:

Agree with Tony on the mechanical non engagement of the pinion.

 

But check all the electrical connections from battery through to starter and the negative returns from engine to battery. You could just have a high resistance connection.

Especially the 'orid multiplug(s) on the main engine wiring harness. It would be a thinnish cable that runs between the start terminal on the ignition switch and the small terminal on the actual motor. In fact you could rule that circuit in or out by making a temporary connection between engine battery pos and that small terminal; on the starter. If you don't make a firm connection you will get sparks but if it starts every time then that suggests it is a high resistance between switch and motor.

Link to comment
Share on other sites

4 minutes ago, Tracy D'arth said:

Agree with Tony on the mechanical non engagement of the pinion.

 

But check all the electrical connections from battery through to starter and the negative returns from engine to battery. You could just have a high resistance connection.

How would any electrical problem be solved by a mechanical movement of the engine?

 

This is a genuine question, I really don't understand.

Link to comment
Share on other sites

2 minutes ago, frahkn said:

First your question; the engine is 19 years old and has nearly 13,000 hours on the clock.

 

The click is when I turn the key, not when I move the pulley.

 

On small movement usually solves the problem but occasionally I have to move it several times, almost a full rotation.

 

So at 13000 hours in private use I would not expect burred flywheel teeth but possible.

 

The last sentence suggest to me, it may well be a lack of electricity causing a lack of "oomph" from the solenoid. Definitely check what Tracy advised to include ensuring the battery terminals mating surfaces are clean and tight. Then check the multiplug(s) connections for tightness and cleanliness. Finally, if you have no luck try the test I suggested. It might be poor contacts in the ignition switch causing resistance. You can test for that by simply shorting between he ignition switch main   input terminal and the start terminal. If it works every time there but no on the key suspect switch contacts.

Link to comment
Share on other sites

8 minutes ago, frahkn said:

How would any electrical problem be solved by a mechanical movement of the engine?

 

This is a genuine question, I really don't understand.

 

If you want to take that line of diagnosis you are not allowing for the embuggerance factor when diagnosing engines. Both Tracy and myself agree on the most likely mechanical issue. We both have also acknowledged it may still be an intermittent electrical fault that cures itself when you crawl around the engine area. It is far easier to test the wiring than it is to get a Beta starter off from what I see.

Link to comment
Share on other sites

10 minutes ago, Tony Brooks said:

 

So at 13000 hours in private use I would not expect burred flywheel teeth but possible.

 

The last sentence suggest to me, it may well be a lack of electricity causing a lack of "oomph" from the solenoid. Definitely check what Tracy advised to include ensuring the battery terminals mating surfaces are clean and tight. Then check the multiplug(s) connections for tightness and cleanliness. Finally, if you have no luck try the test I suggested. It might be poor contacts in the ignition switch causing resistance. You can test for that by simply shorting between he ignition switch main   input terminal and the start terminal. If it works every time there but no on the key suspect switch contacts.

I realise that it can be irritating when someone doesn't just go and make the checks which you advise, and indeed I will make them!

 

First though, can you explain the link between any engine movement and a poor electrical connection.

 

Sorry, posts crossed.

Edited by frahkn
Slow typing
Link to comment
Share on other sites

5 minutes ago, frahkn said:

I realise that it can be irritating when someone doesn't just go and make the checks which you advise, and indeed I will make them!

 

First though, can you explain the link between any engine movement and a poor electrical connection.

 

Sorry, posts crossed.

The problem may not be electrical - take a step back and look at the wider picture. The solenoid may still be getting full current and trying to engage the starter motor, but the damaged flywheel teeth aren't letting it fully engage as said above.

Link to comment
Share on other sites

3 minutes ago, frahkn said:

I realise that it can be irritating when someone doesn't just go and make the checks which you advise, and indeed I will make them!

 

Not in the least bit irritating when there is a dialogue going on. I know suggesting electrical faults seems counterintuitive for the symptoms but that takes no account of bangs (deck boards) and vibrations from moving the engine round possibly temporarily clearing the fault.

 

It MIGHT be the starter pinion falling apart but, you won't know that until the starter is taken off.

It MIGHT be worn brushes in the starter motor preventing the pull in coil developing full power so the hold in coil is not strong enough to close the solenoid contacts on its own or with a reduced pull from the pull in coil.

Link to comment
Share on other sites

If you repeatedly attempt to start without touching the engine does it fail to start...,?

 

I have an intermittent starting issue on a Vetus which sounds similar to yours, I have found if I try starting again it will eventually start but I might retry turning the key 10 times before it starts.  I usually try a couple of times and then wait a few seconds and try again.  I was going to get my starter reconditioned as that was what I was advised but there has been a problem getting the bits.

Link to comment
Share on other sites

7 minutes ago, Rob-M said:

If you repeatedly attempt to start without touching the engine does it fail to start...,?

 

I have an intermittent starting issue on a Vetus which sounds similar to yours, I have found if I try starting again it will eventually start but I might retry turning the key 10 times before it starts.  I usually try a couple of times and then wait a few seconds and try again.  I was going to get my starter reconditioned as that was what I was advised but there has been a problem getting the bits.

Could just as easily be contacts in the switch or, as I think some Vetus engines use a relay between switch and starter that could be at fault.

Link to comment
Share on other sites

Just as an indication - you are not alone.

 

My Yanmar digger has a similar, irritating fault - tun the key, click, tun the key, click, this can happen up to 10 or a dozen times, other times, turn the key and she starts first 'turn'.

 

It will always start 1st turn if the battery is well charged, but if she has been standing for a few weeks I will get 'some' clicks' before she fires up.

 

Check your battery voltage when it happens - there may not be quite enough for the solenoid to get the starter turning over.

Link to comment
Share on other sites

56 minutes ago, frahkn said:

How would any electrical problem be solved by a mechanical movement of the engine?

 

This is a genuine question, I really don't understand.

When you get into the engine hole, you lean/stand/move things. The slightest movement could correct say a poor earth strap on the engine or the dreaded multiplug in the loom.  You have all those exposed bobbins with wires on around the side angles of a Beta.

 

Its not logical but believe me it happens.

Link to comment
Share on other sites

7 minutes ago, Alan de Enfield said:

My Yanmar digger has a similar, irritating fault - tun the key, click, tun the key, click, this can happen up to 10 or a dozen times, other times, turn the key and she starts first 'turn'.

 

 

I've had exactly this on a number of different engines and firstly, a smart tap on the starter motor usually persuades it to start in any one instance of the fault, and secondly in every case a new or recon starter motor has permanently fixed the fault.

 

I reckon it is usually worn out brushes although I've never dismantled a starter to look. 

 

 

Link to comment
Share on other sites

8 minutes ago, MtB said:

I reckon it is usually worn out brushes although I've never dismantled a starter to look

 

Or even dirty/oily brushes or armature surface. That makes sense because the solenoid pull in coil earths via the brushes and armature, so if there is a poor connection not enough current can flow through the coil, so a very weak pull in. The needing to whack the starter also speaks to a brush problem.

 

(The solenoid has two coils, a high current pull in coil and a low current hold in coil. The pull in coil gets de-energized the instant the solenoid contacts close).

Edited by Tony Brooks
Link to comment
Share on other sites

16 minutes ago, MtB said:

 

 

I've had exactly this on a number of different engines and firstly, a smart tap on the starter motor usually persuades it to start in any one instance of the fault, and secondly in every case a new or recon starter motor has permanently fixed the fault.

 

I reckon it is usually worn out brushes although I've never dismantled a starter to look. 

 

 

To quote the immortal words of @Sir Nibble

 

"If you know precisely how it works, you can usually work out precisely why it doesn't " 

 

 

Finks he also said don't smack it with a hammer, though I spose a, tap may be acceptable. 

Edited by rusty69
Link to comment
Share on other sites

34 minutes ago, rusty69 said:

To quote the immortal words of @Sir Nibble

 

"If you know precisely how it works, you can usually work out precisely why it doesn't " 

 

 

Finks he also said don't smack it with a hammer, though I spose a, tap may be acceptable. 

 

 

Ooh I'd never smack it with a hammer! I'd smack it with a tap. 

 

(You set 'em up, I'll knock 'em in...)

 

 

 

image.png.f7ea6966db72b1f9391466d1544c4cad.png

 

 

  • Love 1
Link to comment
Share on other sites

59 minutes ago, rusty69 said:

Finks he also said don't smack it with a hammer, though I spose a, tap may be acceptable. 

 

That can't be repeated often enough, specially if you have no idea about the technology the starter motor uses.

 

If you have a motor with wound (electromagnetic) field coils then feel free to smack away. However, modern geared starters usually use brittle permanent magnet fields and on good smack could easily shatter those magnets and jamb the whole thing up.  I would go as far as to say any other 12V motors you may have on the boat are also likely to be permanent magnet, so no smacking the water pump motor.

 

You are unlikely to do any damage hitting them with the heel of a slipper though.

 

 

 

Link to comment
Share on other sites

8 hours ago, Rob-M said:

If you repeatedly attempt to start without touching the engine does it fail to start...,?

 

I have an intermittent starting issue on a Vetus which sounds similar to yours, I have found if I try starting again it will eventually start but I might retry turning the key 10 times before it starts.  I usually try a couple of times and then wait a few seconds and try again.  I was going to get my starter reconditioned as that was what I was advised but there has been a problem getting the bits.

This is a profound and interesting question, my answer is not so useful.

 

Naturally I am a bit concerned about the state of the state battery (even though the battery monitor says it's ok) so I don't often try multiple times. But once or twice it has started on the third attempt.

 

Also your question reminds me that I had a similar problem about seven years ago which led me to buy a new ignition switch (which I never fitted because the problem 'went away').Perhaps now would be the time to fit it.

Link to comment
Share on other sites

8 hours ago, Tony Brooks said:

 

Not in the least bit irritating when there is a dialogue going on. I know suggesting electrical faults seems counterintuitive for the symptoms but that takes no account of bangs (deck boards) and vibrations from moving the engine round possibly temporarily clearing the fault.

 

It MIGHT be the starter pinion falling apart but, you won't know that until the starter is taken off.

It MIGHT be worn brushes in the starter motor preventing the pull in coil developing full power so the hold in coil is not strong enough to close the solenoid contacts on its own or with a reduced pull from the pull in coil.

Let me just say that when the problem first occurred (last year) I thought the solenoid was buggered and phoned RCR. A fitter came but didn't have the parts so had to return next day.

 

In the interim he showed me the 'work around' turning the pulley (I would never have imagined that such a thing would work).

 

When he came back he fitted a new starter motor and the problem was solved for a few months. When it reoccured I haven't felt able to phone them because its so intermittent.

 

So I'm assuming the starter motor is less likely to be the cause.

 

You can perhaps see why I didn't want to go into all this at the outset.

Link to comment
Share on other sites

8 hours ago, frahkn said:

Naturally I am a bit concerned about the state of the state battery (even though the battery monitor says it's ok)

 

Assumption is the mother of all cock-ups - don't know who said it remains a truism.

 

1. Battery monitors normally only give details about the domestic battery, not the start battery, unless you have two shunts, one in each circuit, but that is rare.

 

2. If you want to test the start battery connect a multimeter set to 20V DC across the battery and spin the starter for about 20 seconds. If the battery can maintain 10V while cranking it is very unlikely to be a battery problem. 10V is a Lucas figure, I would accept 9.8 ish as long as it was not dropping.

 

3. If the flywheel teeth are burred then when they mesh they can damage the teeth on the starter pinion. Did the RCR chap carefully inspect the flywheel teeth.

 

4. By all means fit the switch, but it is simple to rule out by connecting the switch's main 12V+ terminal to the start terminal with a short length of wire, that simulates the switch action. If it spins every time it is unlikely to be the switch.

 

This is just my observations and opinion. I get the impression that the size of cables used by a number of marinisers for their engine        harnesses is very often marginal at best, particularly the start cable and any glow pug cable. This causes volt drop and thus a lack of force from the solenoid. People fitting a relay close to the starter tends to confirm this. A voltmeter connected between battery + and the small start terminal on the motor/solenoid should read less than 0.5 volts while cranking (ignore what it reads before and after cranking, it will probably be battery voltage, but it is meaningless). The higher the reading the more resistance there is in the whole circuit, so it could be a resistive switch, dirty/loose terminals, or undersized cables.

Edited by Tony Brooks
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.