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starter motor issue


frahkn
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Last year we had a starter motor problem - turning the key we heard just a click but the engine didn't turn over.

 

The RCR engineer got it started but said it needed a new starter motor, he would bring it next day but as we were close to our home marina, would prefer to fit it there.

 

He showed us a "workaround" in case it wouldn't start in the morning; we should turn the crankshaft pulley a bit and try the starter again. This worked and we returned to base, had the new starter fitted and all was solved.

 

Having returned to the boat after 6 months, we now have the same but intermittent problem with starting. The pulley solution still works but I am confused - what starter motor problem does this suggest?

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2 minutes ago, Tracy D'arth said:

Bad ring gear possibly.  Could be poor wiring reducing the current for the solenoid but I would have expected turning the engine over a bit would make no difference.

 

What engine?

Hi Tracy, Beta 43.

 

That is my problem - the click suggests solenoid but why should turning the crankshaft (sometimes only an inch or so) fix the problem?  

 

 

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3 minutes ago, frahkn said:

Hi Tracy, Beta 43.

 

That is my problem - the click suggests solenoid but why should turning the crankshaft (sometimes only an inch or so) fix the problem?  

 

 

The starter pinion is hitting the ring gear rather than engaging the teeth, which prevents the solenoid travelling fully so the contacts in the rear which power the motor  do not connect.

Could be simply a burred section of the ring gear.

Are you certain the correct starter was fitted?  The lead on the gear teeth could be the wrong way.

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Re. Tracy's query re correct starter motor, Beta are pretty good at matching or supplying spare parts so if the RCR people obtained a generic starter from some other source that might be a possibility. Could well be worth a call to Beta. I wouldn't think its a common problem but its the turning the crankshaft bit that puzzles me.

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15 minutes ago, Bee said:

Re. Tracy's query re correct starter motor, Beta are pretty good at matching or supplying spare parts so if the RCR people obtained a generic starter from some other source that might be a possibility. Could well be worth a call to Beta. I wouldn't think its a common problem but its the turning the crankshaft bit that puzzles me.

It's quite common for engines to come to rest in the same position when they stop. This means that the starter tends to engage on the same part of the ring gear every time you start the engine. Over time the normal wear and tear is localised and can eventually lead to damage on the leading edge of the pinion and the starter facing side of the ring gear. Failure to engage will be infrequent at first, but the damage then tends to accelerate, leading to a total failure to engage. Turning the engine a few degrees by hand presents an undamaged section of ring gear to the (now newer) starter pinion.

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2 minutes ago, Eeyore said:

It's quite common for engines to come to rest in the same position when they stop. This means that the starter tends to engage on the same part of the ring gear every time you start the engine. Over time the normal wear and tear is localised and can eventually lead to damage on the leading edge of the pinion and the starter facing side of the ring gear. Failure to engage will be infrequent at first, but the damage then tends to accelerate, leading to a total failure to engage. Turning the engine a few degrees by hand presents an undamaged section of ring gear to the (now newer) starter pinion.

I reckon that this is favourite too. May be worth whipping the starter out and filing the burrs off the ring gear. Unusual, this happens much less now that we have pre-engage starters.

Edited by Tracy D'arth
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Thanks for all the info, particularly as it is quite focused.  It is an 18 year old engine with 11k hours under its belt.

 

I don't know if it was a genuine Beta spare, at my age I can't get down to see it and as RCR did not charge me for it, they did not provide any paperwork.

 

One thing I would say is that sometimes you only need to move the engine by a few degrees and it will start but sometimes 5 different moves are required before it will work.

 

Thanks again.

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I would suggest trying shorting out +be to the solenoid terminal instead of turning the flywheel. All pre engaged starters are designed with a spring somewhere between the solenoid and drive assembly, if the pinion hits the flywheel tooth to tooth the solenoid should compress the spring to complete its travel and the pinion will snap into mesh when the starter begins to turn as the contacts close. It sounds like the solenoid lacks the power to compress the spring and I would suspect volt drop.

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2 hours ago, Sir Nibble said:

I would suggest trying shorting out +be to the solenoid terminal instead of turning the flywheel. All pre engaged starters are designed with a spring somewhere between the solenoid and drive assembly, if the pinion hits the flywheel tooth to tooth the solenoid should compress the spring to complete its travel and the pinion will snap into mesh when the starter begins to turn as the contacts close. It sounds like the solenoid lacks the power to compress the spring and I would suspect volt drop.

Very grateful for the above but I don't fully understand it. Can you explain (in words suited to an idiot) what should be shorted to what.

 

Thanks.

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The next time it won't engage the starter and just clicks, without turning the engine,  short the small tag on the back of the solenoid ( the bit on the top of the starter with all the wires going to it ) to the big nut on the back of the solenoid holding the thick wire which goes off to the battery.

It may spark a bit.

If the motor then engages and spins up, you have a high resistance somewhere in that wire to the tag on the solenoid from the ignition switch. Favorite culprit is any multiplugs on the engine wiring loom up to the control panel.

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23 minutes ago, Tracy D'arth said:

The next time it won't engage the starter and just clicks, without turning the engine,  short the small tag on the back of the solenoid ( the bit on the top of the starter with all the wires going to it ) to the big nut on the back of the solenoid holding the thick wire which goes off to the battery.

It may spark a bit.

If the motor then engages and spins up, you have a high resistance somewhere in that wire to the tag on the solenoid from the ignition switch. Favorite culprit is any multiplugs on the engine wiring loom up to the control panel.

And favourite fix is to fit a relay.

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31 minutes ago, Tracy D'arth said:

The next time it won't engage the starter and just clicks, without turning the engine,  short the small tag on the back of the solenoid ( the bit on the top of the starter with all the wires going to it ) to the big nut on the back of the solenoid holding the thick wire which goes off to the battery.

It may spark a bit.

If the motor then engages and spins up, you have a high resistance somewhere in that wire to the tag on the solenoid from the ignition switch. Favorite culprit is any multiplugs on the engine wiring loom up to the control panel.

 

That advice is good but might be a bit misleading, it misled me until I studied it for a while. The starter will have maybe four terminals on it. One or two larger ones with very thick wires running to them with nuts. If its two then on is the negative and its wire will usually go to an engine bed or the engine block. You need the other one that often has one large and a or some thin wires on it. There may be another larger one that is close to the larger cylindrical starter body - ignore that one. There will be a small terminal with a single thin wire on it. This is the one that energises the solenoid. So what they are saying is next time it just clicks get an old  heavy screwdriver the very firmly use it t connect that large terminal and the small on with the single wire on it. The firmer and more positive you are the fewer sparks you will create.

 

Typical starters look like this one:

 

 

You need the energise connection (it may be a nut type) and the main positive.

prengst.jpg

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5 minutes ago, Tony Brooks said:

 

 So what they are saying is next time it just clicks get an old  heavy screwdriver the very firmly use it t connect that large terminal and the small on with the single wire on it. The firmer and more positive you are the fewer sparks you will create..........................

 

 

 

 

The wiring on my old JCB 3C was 'excluding-wiring' and the only way to start it was a spanner across the solenoid - YOU WILL get a good display of sparks if you do not make a very firm contact, it will make you jump and you will autonatically pull your hand away.

 

You will not get a shock, it will not hurt, it is just a bit frightening.

 

Keep doing it until you can actually keep the screwdriver / spanner in place long enough to turn the starter over.

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22 minutes ago, Sir Nibble said:

And favourite fix is to fit a relay.

 

Don't disagree and that's the thing you can to overcome an undersized wiring issue but if its a resistive ignition switch then fitting a relay only covers up a faulty item so if its established it starts reliably by the screwdriver a further test or tests should be done to identify where the volt drop is actually occurring.

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2 hours ago, Tony Brooks said:

 

That advice is good but might be a bit misleading, it misled me until I studied it for a while. The starter will have maybe four terminals on it. One or two larger ones with very thick wires running to them with nuts. If its two then on is the negative and its wire will usually go to an engine bed or the engine block. You need the other one that often has one large and a or some thin wires on it. There may be another larger one that is close to the larger cylindrical starter body - ignore that one. There will be a small terminal with a single thin wire on it. This is the one that energises the solenoid. So what they are saying is next time it just clicks get an old  heavy screwdriver the very firmly use it t connect that large terminal and the small on with the single wire on it. The firmer and more positive you are the fewer sparks you will create.

 

Typical starters look like this one:

 

 

You need the energise connection (it may be a nut type) and the main positive.

prengst.jpg

Tony, 

 

Just to be sure, am I to short the "main battery pos. terminal" to the "energise terminal" in your diagram?

 

The engine is about 12 feet from the ignition switch, do I need to have that switch in the 'ignition' position while shorting or just in the 'on' position?

 

The starter is directly below the gearbox oil cooler, so from a standing position I cannot see any of the above. I may be able to get down and see it but it will take some time, will this be a problem (ignition switch wise)?

 

Thanks.

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1 hour ago, frahkn said:

Tony, 

 

Just to be sure, am I to short the "main battery pos. terminal" to the "energise terminal" in your diagram?

 

The engine is about 12 feet from the ignition switch, do I need to have that switch in the 'ignition' position while shorting or just in the 'on' position?

 

The starter is directly below the gearbox oil cooler, so from a standing position I cannot see any of the above. I may be able to get down and see it but it will take some time, will this be a problem (ignition switch wise)?

 

Thanks.

 

It won't matter what position the ignition switch is in because you will be physically making the electrical connection on the starter that the ignition switch and wiring makes in the switch. If you have an electric stop where the engine stops when you turn the ignition off then leave the ignition off, otherwise the engine may actually start. If its a pull cable, stop position on the key or push button stop then it won't start so it won't matter. It won't matter if the engine does start as long as your hands etc. are clear of any moving parts but because you are likely to be up close and personal to the engine it might make you jump.

 

Yes, main battery pos. to energise terminal.

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5 hours ago, Tony Brooks said:

 

It won't matter what position the ignition switch is in because you will be physically making the electrical connection on the starter that the ignition switch and wiring makes in the switch. If you have an electric stop where the engine stops when you turn the ignition off then leave the ignition off, otherwise the engine may actually start. If its a pull cable, stop position on the key or push button stop then it won't start so it won't matter. It won't matter if the engine does start as long as your hands etc. are clear of any moving parts but because you are likely to be up close and personal to the engine it might make you jump.

 

Yes, main battery pos. to energise terminal.

Thank you all very much. I'll have a go when next it fails to start.

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On 02/05/2021 at 23:02, frahkn said:

Thanks for all the info, particularly as it is quite focused.  It is an 18 year old engine with 11k hours under its belt.

 

 

Maybe you should think about changing the belt?

 

I'll get me coat...

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