Beta Marine 28 starter motor removal problems

[Tony Brooks]

If it's a hydraulic gearbox, turning the prop shaft without the engine running will not turn the engine. On a mechanical box it might well do depend upon if rotation is used to force the clutches together or a dog clutch is used.

 

Photo or make and model of gearbox.

[Karen Lea Rainey]

3 minutes ago, Tony Brooks said:

If it's a hydraulic gearbox, turning the prop shaft without the engine running will not turn the engine. On a mechanical box it might well do depend upon if rotation is used to force the clutches together or a dog clutch is used.

 

Photo or make and model of gearbox.

 Hi Tony, haven't got a picture of it in situe, but on a survey from 2016 it is a PRM 120 mechanical gearbox. I do believe it is still the same one.

Its identical to this one but it's in alloy silver.

[Tony Brooks]

That is a mechanical box and I would hope putting it in gear would allow the shaft to drive the flywheel, but as I say it all depends upon how it engages. I hope a member who has had one apart can be more definite.

[Tracy D'arth]

23 minutes ago, Karen Lea Rainey said:

UPDATE. UPDATE. UPDATE.

Got wobble extension bars lined up, under the (slipped to the side alternator) 12mm bolt 

Removed the starter motor, it looks ok, no worn teeth, springs ok, bench test says it spins ok.

Now, I turn the coupling drive shaft by putting a very large screwdriver between the bolts, put it in gear and its turns quite freely, it only turns one way, put it in reverse and do the same, again it turns without too much effort.

 

Now because the starter motor is off, I can touch the teeth on the flywheel.

 

I now expect the turning of the  drive shaft to turn the flywheel at the same time.  ITS NOT MOVING THE FLYWHEEL AT ALL.

Does this therefore mean that the gearbox is responsible for the problem and that the wacking sound was the starter bendix thumping into the flywheel instead of meshing the pinion , therefore unable to turn the crankshaft/ flywheel.

Could it be a drive plate / clutch problem, it sounds as though the gearbox is next to come out, but that is beyond me.

Thanks again for your inputs, They are excellent knowledge for which I am grateful.

I am not surprised that turning the output shaft of the gearbox fails to turn the flywheel. The gearbox has a friction cone clutch which is not a positive drive but one that relies on speed and oil on the cone to engage.

 

Now you can get to the flywheel, try prying it round with a large screwdriver in the gear teeth against the edge of the starter hole. Try to turn it in the running direction clockwise looking at the front, belt end of the engine, for at least one full revolution, you may feel two points where the compression makes it more difficult to turn, this is normal. You may also see the valve rockers move looking in the oil filler cap.

Edited August 11, 2021 by Tracy D'arth

[Karen Lea Rainey]

9 minutes ago, Tracy D'arth said:

I am not surprised that turning the output shaft of the gearbox fails to turn the flywheel. The gearbox has a friction cone clutch which is not a positive drive but one that relies on speed and oil on the cone to engage.

 

Now you can get to the flywheel, try prying it round with a large screwdriver in the gear teeth against the edge of the starter hole. Try to turn it in the running direction clockwise looking at the front, belt end of the engine, for at least one full revolution, you may feel two points where the compression makes it more difficult to turn, this is normal. You may also see the valve rockers move looking in the oil filler cap.

Will do that tomorrow now, good strong screwdriver at the ready. Should it move with the prying of a screwdriver?

[Sir Nibble]

And here's the word of the law.

I've been rebuilding starters for 48 years,  it's what I do. Done hundreds of those Nippon Denso starters like yours with the offset motor. There's only one thing goes wrong with them, the solenoid contacts. Cheap and easy. Symptoms.......  turn key: CLUNK! (Silence).

[Karen Lea Rainey]

1 hour ago, Tracy D'arth said:

I am not surprised that turning the output shaft of the gearbox fails to turn the flywheel. The gearbox has a friction cone clutch which is not a positive drive but one that relies on speed and oil on the cone to engage.

 

Now you can get to the flywheel, try prying it round with a large screwdriver in the gear teeth against the edge of the starter hole. Try to turn it in the running direction clockwise looking at the front, belt end of the engine, for at least one full revolution, you may feel two points where the compression makes it more difficult to turn, this is normal. You may also see the valve rockers move looking in the oil filler cap.

Q. Thank you for your knowledge so far.

Tomorrow morning I will tackle the flywheel with the screwdriver trick. If it moves albeit hesitantly at points on the wheel, then am I right in thinking that going forward from that the crankshaft/pistons etc are ok.

 

Then thinking this through, the gear box feels ok moving the lever control in forward / reverse, so my brain tells me 

The drive plate is no longer connected to the flywheel, this would also explain why the bendix pinion is not meshing with the flywheel and that's why the very loud whack/ clunk is heard because the pinion cannot engage with the flywheel ( basically it out of line from the splines and bolts on the drive plate.)

Do you think the drive plate could be no longer attached to the flywheel, bolts may have sheared off or worked loose over time.

Have you ever heard of such a thing happening before?

 

Following on from there, I could just about learn / try to replace the drive plate.

As I understand it, do the following.

Remove engine oil as as much as possible.?

Unbolt coupling from propellor, move shaft backwards to allow,

Unbolt gearbox from the flywheel, slide off the splines ,put aside presuming no problems with it.

Remove bell housing / side of flywheel. 

Inspect drive plate.

Would I then expect to see a completely unattached drive plate, where would the bolts be?

Or do you think they would just be snapped and present.?

Could the bolts be sitting in the bottom of the flywheel housing?

 

When I was turning the driveshaft earlier,  because of the splines on the gearbox/ driveplate , it wasnt moving the flywheel, and obviously the flywheel was not lined up with the starter pinion.

Hence the back to the first question!

Will the crankshaft/ pistons  be expected to move when I do the big screwdriver trick?

[Tony Brooks]

Sir N, our starter and alternator expert, has told you that the contacts on your starter is a known weak spot and that fits with the initial symptoms.

 

Tracy has told you and I hinted that even a mechanical box may not engage the gears unless the engine is running.

 

You seem to have  extrapolated from this that the drive plate is not connected to the flywheel and I can't see how you have come to that conclusions. You also seem to have  decided that a drive plate to flywheel problem will prevent the pinion engaging with the flywheel. Again, I see no justification for that conclusion. First the flywheel and pinion teeth normally have matching tapers on them so even if not 100% lined up they will still mesh, and also, often the pinion rotates as it is moved into mesh with the flywheel. Any wear on the flywheel teeth will be concentrate in two small areas.

 

Before you try turning the flywheel, forget any thoughts of the drive plate being the cause. If you can't lever the flywheel round, then it may be worth taking the gearbox and adaptor plate off to have a look before taking the cylinder head off. As Tracy has told you, it would be a good idea to take the rocker cover off  before trying to turn the flywheel so you can see what the valves are doing and compare their positions and distances moved.

 

We all hope the flywheel will move. If it does go all the way round in both directions it will indicate the start battery is flat, there is a starting wiring problem, or it's the starter solenoid contact. Less likely would be an out-and-out starter or pinion fault.

 

 

 

 

[Sir Nibble]

The pinion meshes, the contacts don't close. They're heavily worn, always are. (This is going to be the one in a million that makes a tit out of me isn't it).

There's a five sided cover on the end of the solenoid, held with 3 screws. Take it off, pull the plunger out and there they are. 

[Cheshire cat]

If Sir N is right does that mean that the contacts have oxidised while they've say there doing nothing for two years? Is there any mileage in cleaning them up to attempt to get the starter to turn the engine over? Obviously this is not a permanent solution but would prevent lots of unnecessary dismantling.

[Karen Lea Rainey]

31 minutes ago, Tony Brooks said:

Sir N, our starter and alternator expert, has told you that the contacts on your starter is a known weak spot and that fits with the initial symptoms.

 

Tracy has told you and I hinted that even a mechanical box may not engage the gears unless the engine is running.

 

You seem to have  extrapolated from this that the drive plate is not connected to the flywheel and I can't see how you have come to that conclusions. You also seem to have  decided that a drive plate to flywheel problem will prevent the pinion engaging with the flywheel. Again, I see no justification for that conclusion. First the flywheel and pinion teeth normally have matching tapers on them so even if not 100% lined up they will still mesh, and also, often the pinion rotates as it is moved into mesh with the flywheel. Any wear on the flywheel teeth will be concentrate in two small areas.

 

Before you try turning the flywheel, forget any thoughts of the drive plate being the cause. If you can't lever the flywheel round, then it may be worth taking the gearbox and adaptor plate off to have a look before taking the cylinder head off. As Tracy has told you, it would be a good idea to take the rocker cover off  before trying to turn the flywheel so you can see what the valves are doing and compare their positions and distances moved.

 

We all hope the flywheel will move. If it does go all the way round in both directions it will indicate the start battery is flat, there is a starting wiring problem, or it's the starter solenoid contact. Less likely would be an out-and-out starter or pinion fault.

 

 

Thanks Tony, I'm ahead of myself, rocker cover off tomorrow once I get the flywheel to move with a good screwdriver prying it round as best I can.

Will report back with findings tea time tomorrow. Thanks again.

 

 

[Karen Lea Rainey]

30 minutes ago, Sir Nibble said:

The pinion meshes, the contacts don't close. They're heavily worn, always are. (This is going to be the one in a million that makes a tit out of me isn't it).

There's a five sided cover on the end of the solenoid, held with 3 screws. Take it off, pull the plunger out and there they are. 

Picture is starter attached, I do believe it's a denso nippon, worked ok on battery test  earlier at home.

Hopefully a better picture of the pinion.

[Sir Nibble]

That's the one for sure. 3 small screws,  take a look. 

[ditchcrawler]

12 hours ago, Tracy D'arth said:

 

 

One possibility that has just struck me is a snapped crank. Rare but I have had it happen on a Rootes group engine many years ago. That would only turn over so far before locking up. Its certainly an odd one.

I saw a car drive into a garage with a bust crank with my own eyes. If you got hold of the front pulley you could pull it forward a bit. I didn't see it stripped down but understand in snapped in the main bearing

[Karen Lea Rainey]

21 hours ago, David Mack said:

 

It could be the water pump or alternator that has jammed. Try removing the drive belt and then see if the engine will turnover/start.

Thanks David, tried that, still no joy. Got the same whack/ clunk from the starter

[Tony Brooks]

12 hours ago, Karen Lea Rainey said:

Picture is starter attached, I do believe it's a denso nippon, worked ok on battery test  earlier at home.

 

 

 

If it worked OK at home, then that suggest the contacts are less likely to be the problem and that the motor is OK. That in turn suggests if it is starter related it's a flat start battery, dirty battery terminals or the wiring. However, none of that is in nay way certain because it could still be an engine problem and we won't know about that until you try to  lever the engine over by the flywheel. Once you have done that we and you will have  a much better idea of what to do next.

[Karen Lea Rainey]

Thank you Tony, I'm  on my way there shortly and will report back.

I will start at the beginning again, with check battery voltage, check all terminal posts for clean bright connections.

Then address the flywheel with a screwdriver leverage,  I am nervous about putting a racket socket and extension bar on one of the 3 small nuts on the end of the front crankcase, there is no central nut. Will i shear the nut off?

Remove rocker cover to see valves moving hopefully.

I have a new starter motor in hand later today, just incase the old one is at fault and has a weak bendix, worn threads and I will put that that on around teatime if all seems well before hand.

I have spoken to the previous owners this morning to clarify when the breakdown/ tow into the marina happened and they told me

it was" early last year".

So the boat has sat in the marina for over 12 months without attendance, but the batteries were on float charge throughout.

Now the truth or part of it is coming out from the previous owners.

So , start at the beginning again, check batteries, and take it from there.

 

Will report back later.

[Tony Brooks]

5 minutes ago, Karen Lea Rainey said:

Thank you Tony, I'm  on my way there shortly and will report back.

I will start at the beginning again, with check battery voltage, check all terminal posts for clean bright connections.

Then address the flywheel with a screwdriver leverage,  I am nervous about putting a racket socket and extension bar on one of the 3 small nuts on the end of the front crankcase, there is no central nut. Will i shear the nut off?

Remove rocker cover to see valves moving hopefully.

I have a new starter motor in hand later today, just incase the old one is at fault and has a weak bendix, worn threads and I will put that that on around teatime if all seems well before hand.

I have spoken to the previous owners this morning to clarify when the breakdown/ tow into the marina happened and they told me

it was" early last year".

So the boat has sat in the marina for over 12 months without attendance, but the batteries were on float charge throughout.

Now the truth or part of it is coming out from the previous owners.

So , start at the beginning again, check batteries, and take it from there.

 

Will report back later.

 

You can't really check the battery without the starter in place unless you have a high rate discharge tester suitable for the battery size and type, so lever the flywheel first. If it goes round two revolutions in both directions, refit the starter. Then leave the voltmeter on the battery while you try cranking it. The voltage should stay above about 10.8 volts. If it drops more, then the battery is suspect. In that case, get someone to hold the meter probes on the lead battery posts rather than the terminals. If the result is the same, then it confirms a flat/faulty battery. If  the voltage does not drop as much, clean the terminals.

[Tracy D'arth]

I cannot believe that the previous owners did not find out what was wrong with the engine when they towed it in.

To have an engine that failed overnight and then to just sell the boat off at a reduced price without exploring the reason for the breakdown or the cost of repairs does not ring true with me at all.

 

You have bought the boat, so why can they not be honest now and tell you what is wrong with it?

[MtB]

My own reading of it is the sequence of events was perhaps slightly different from what they remember. I'd guess what actually happened was the engine spontaneously stopped running late in the day (probably overheated) so they moored up for the night, hoping it would start again in the morning.

 

But when it didn't start they called a breakdown bod who after a cursory check established the engine was seized and with no further investigation told them a new engine costing £10k all inclusive was required. Hence the tow back to the yard and selling it cheap. 

[Tony Brooks]

24 minutes ago, Tracy D'arth said:

I cannot believe that the previous owners did not find out what was wrong with the engine when they towed it in.

To have an engine that failed overnight and then to just sell the boat off at a reduced price without exploring the reason for the breakdown or the cost of repairs does not ring true with me at all.

 

You have bought the boat, so why can they not be honest now and tell you what is wrong with it?

 

I suspect they don't really know and if they told some engineers what they thought was wrong  in terms like the OP did here they may well have been given a worse case price, and it may have been an "I don't want the job" price. Could be enough to tip them towards just getting rid. Although I very much doubt it, at this stage we could be talking a new engine if a crank has broken. What would that be professionally fitted £8000 to £10,000?

 

Seems Mike and myself have similar thoughts

 

Edited August 12, 2021 by Tony Brooks

[BEngo]

Sorry all but we seem to be barking up the wrong tree here.

Sir Nibble has proven over the years that he knows his stuff.  He says the starter motor contacts are likely to be knackered, and wil give just the symptoms the OP is reporting.  Motor turns, pinion engages, loud clunk as it does, main contacts don't close   so no power.  It won't turn the engine over but will turn apparently happily on the bench.   Apply Occams Razor.  What is the simplest possible cause of the problem?  THE STARTER!

 

The starter notor contacts check is simple so that is the next thing to do, before chasing interesting but unlikely and harder to check possibilities.

 

N  

[Tony Brooks]

6 minutes ago, BEngo said:

Sorry all but we seem to be barking up the wrong tree here.

Sir Nibble has proven over the years that he knows his stuff.  He says the starter motor contacts are likely to be knackered, and wil give just the symptoms the OP is reporting.  Motor turns, pinion engages, loud clunk as it does, main contacts don't close   so no power.  It won't turn the engine over but will turn apparently happily on the bench.   Apply Occams Razor.  What is the simplest possible cause of the problem?  THE STARTER!

 

The starter notor contacts check is simple so that is the next thing to do, before chasing interesting but unlikely and harder to check possibilities.

 

N  

 

Except the OP did say the motor got hot - open or resistive contacts = no or reduced current flow, She also says it so no or less warming of the motor. She also said it ran OK at home.  I agree that does not totally rule out resistive contacts or that she may have mistaken the movement caused by the pull in coil current as sufficient  but we can't be sure.

 

The motor heating seem a bit more consistent with low battery voltage at the starter than contacts, but a seized engine would also cause the motor to heat.

 

I agree about Sir N, but the odd thing does not seem to be consistent with the motor contacts. We need to establish if she can lever the flywheel round and she will report back on that.

[MtB]

1 hour ago, BEngo said:

Sorry all but we seem to be barking up the wrong tree here.

Sir Nibble has proven over the years that he knows his stuff.  He says the starter motor contacts are likely to be knackered, and wil give just the symptoms the OP is reporting.  Motor turns, pinion engages, loud clunk as it does, main contacts don't close   so no power.  It won't turn the engine over but will turn apparently happily on the bench.   Apply Occams Razor.  What is the simplest possible cause of the problem?  THE STARTER!

 

The starter notor contacts check is simple so that is the next thing to do, before chasing interesting but unlikely and harder to check possibilities.

 

N  

 

Yes that Occam bloke is probably right, but with the starter out it is only about a minute's work to use a big screwdriver engaged in the teeth of the starter ring to see if the engine rotates at all, and if it does, to see if it goes round two whole revolutions. 

 

This would rule in or out SO MANY possibilities. Dear OP, please do this and report the result.

[Cheshire cat]

I'm surprised you are advocating turning the motor over using a screwdriver on the flywheel.

 

I wouldn't have expected it would be possible to overcome the compression. I've done it on a petrol engine but that would have a lower compression and it's always possible to take the plugs out.

 

It will be interesting to read tonight's installment.