VicS
Well-Known Member
Make yourself a pair of long meter leads with croc clips on the ends .......... use "exrra flexible" wire ( 55/0.1 or similar ) from Maplin or Rapid Electronics
Sticking starter solenoid - I think.
- Thread starter jsl
- Start date
Make yourself a pair of long meter leads with croc clips on the ends .......... use "exrra flexible" wire ( 55/0.1 or similar ) from Maplin or Rapid Electronics
jsl
Well-Known Member
Of course! Duh! I'd be lost without this sort of really helpful advice.
Airscrew
Well-Known Member
Third Engines, All.
I have read this, and other threads through, and rather than start a new thread, I think my problem and solution are here.
Centaur, MD11C, and I am new to this boat and engine. Engine experience is limited to minis, alfas and escorts in the 80's.
Engine normally starts well and is predictable. Yesterday the engine started 'reluctantly'. Let it run for a few minutes, did a alternator/battery check, 13.2/12.4, all good. Restart was OK. Went for a short sail, but engine wouldn't start coming back up the Hamble. Managed to sail OK onto the Warsash visitor pontoon to do some checks.
Batteries are good, 9 months old, and the smartgauge and 'plumbed-in' multi meter (by previous owner) shows fully charged.
I am now (yesterday in Warsash) thinking that the 'reluctant' start now like a starter motor windings problem.
However, on the pontoon, turning the key gives:
nothing from the starter motor, no click or sound from the solenoid, the ignition lights go out, and the temp gauge goes to zero (ie no volts to the starter panel with the key turned), but the other electrics unaffected (VHF, lights, plotter), so the 'short' is only in the starter circuit.
So now it sounds like the solenoid, but a sluggish starter motor an hour before that. Does this sound like a conflict, or is this logical? I may have two problems, not one.
I didnt have a large hammer, but tapping with a large screwdriver on the solenoid didnt help. I will return with a selection of larger hammers.
Should I have done this also with the key turned?
I only had 15mins to diagnose, as I was kindly offered a tow back to our mid-stream pontoon and then to shore. So I will go back to the boat to try and diagnose this Saturday when I have a whole day. I have a (2nd) multimeter in the tool back, but will get some long leads and croc-clips.
Questions.
Do we agree it sounds like the solenoid?
I have read TE's (quoted) text, but need some clarification and further (slower and more detailed) explanation.
The first terminal you refer to will be a +ve direct from the battery (via isolator). So this is the starter motor +ve. Yes? Should this see 12v permanently, or only when the key is turned (switched). What should I see on this terminal IF the starter motor is good but not turning and the solenoid bad? I am guessing 12v.
The 2nd terminal is the solenoid +ve, Yes? I didnt see this terminal, but it sounds like a heavy cable. Does this cable come from the starter panel or from the battery, or is there another relay between this cable and the starter panel? If I see 10 to 12v here, but no movement from the solenoid, does this show the wiring (ir connections) are good, but a mechanical problem in the solenoid?
I have looked, but couldn't find.
Can anyone send me a link to a starter circuit diagram?
Lastly, does anyone have experience of removing the whole starter from an MD11?
Access to the front (flywheel end) of the starter is good. Access to the back is poor.
How many bolts, where?
How many wires, where?
Do I need to remove anything else to do it?
Many many thanks in advance for any additional help here....
<152587>
...
Ok so all is well with other circuits, the fact when you load the control panel with the solenoid the lecky disappears indicates a high resistance somewhere in the supply to the engine panel. If you lean on the start button for say about 10-15 seconds feeling around the supply cables you may detect some warming of the cable or fittings indicating the fault. With the multimeter set to 12volts connect one end to the probe at the supply end and the other probe to the terminal at the engine panel if when the start circuit is invoked the voltage reading on the meter should be virtually zero. Do this on both cables(+ and -) If the meter reads any voltage at all subtract the indicated figure from supply voltage to calculate voltage drop.
VicS
Well-Known Member
I agree most likely a bad connection. Either on the main positive cable to the engine (not the supply from the engine to the panel though) or the negative return from the block.
No problem removing the starter from an MD11C ..If you have to. IIRC just two bolts and the electrical connections.
Big wire from battery/isolator on one terminal together with the alternator output and feed to control panel ( via fuse ) .... all should be red ??
Small white wire on small terminal
Disconnect the the battery before touching the electrical connections though... and be sure you know whats connected to what.
There is a wiring diagram in the owner's manual.
Last edited:
Airscrew
Well-Known Member
Thanks Vic, yes, I now have found the wiring diagram in the manual (only one page, so I missed it first time). Wiring and mechanics in one diag, Seeing it helps alot.
Airscrew
Well-Known Member
Thanks TE.
If I understand you, this approach is looking for heat in he switched, low power cables, and therefore a voltage drop caused by a poor connection.
From the your comments and also Vic, my plan now is:
1. Bigger hammer. Do I tap while turing the key or not?
2. Look for heat, connection problems on the low power, switched cables. Remake where needed.
3. Check and remake all connections back to the battery, both + and -ve. I will also treat this as a learning exercise, as the electrics were all redone before my recent acquision, and very neatly I have to say. Lots of camera pics on the way.
4. After the above, the problem is either internal or mechanical. Remove and take to the becnh at home, then perhaps to an auto electric specialist.
Any additional thoughts or comment??
Also, I should have added in my first post that the engine turns over by hand. So no lockage. That was one of the first things I checked.
Again, many thanks.
RichardS
N/A
Your advice about sticking brushes is spot on ..... I stripped down a motor a few weeks ago and all 4 brushes were their full length but all 4 were corroded into the brush holders and had lost contact with the commutator. The problem with this motor is that it is exposed to some rain spray through the radiator grill and that it is the third "serious overheat" engine fan and if the engine never overheats, which in the UK climate it doesn't, then it never activates so has sat corroding for 20 years. I've now put in an override link so I can activate it manually and keep the brushes moving. Obviously this is a very special case and wouldn't normally apply to any motor which gets used.
I'm not sure I would advise leaning on the start button if using it is presumably drawing enough current to shut down the starter panel and would be concerned about burning something out and making the original problem worse.
Richard
jsl
Well-Known Member
Just a word of thanks again from the originator of this thread. Solenoid was my problem: quite rusty. Revitalised by a good chap in Botley. Motor itself reported to be in surprisingly good nick for its age. Removal and re-installation needed two confident people, so I did not (much) mind paying.
Airscrew
Well-Known Member
One further, and more brutal thought.
Before checking through every connection, in order to check the operation (or not) of the solenoid and starter, is it
A. Possible
B. Sensible
C. Not at all sensible
D. Will damage other electrics, plus C,
to connect, ie with a jump cable, direct from the +ve (battery or switched side of the isolator) to the +ve post, either solenoid or starter.
Safety is one factor, flywheel and alternator belt. Spark is another. I figure I could rig this with the steps in place, running the cable back and up into the cockpit, and make the connection out in the open, ie using two jump leads on the positive side.
Before checking through every connection, in order to check the operation (or not) of the solenoid and starter, is it
A. Possible
B. Sensible
C. Not at all sensible
D. Will damage other electrics, plus C,
to connect, ie with a jump cable, direct from the +ve (battery or switched side of the isolator) to the +ve post, either solenoid or starter.
Safety is one factor, flywheel and alternator belt. Spark is another. I figure I could rig this with the steps in place, running the cable back and up into the cockpit, and make the connection out in the open, ie using two jump leads on the positive side.
Airscrew
Well-Known Member
RichardS
N/A
Certainly a common test for a starter motor/solenoid is to bridge the connections although with a pre-engaged starter it's not always possible to connect to the starter motor directly as the connection through the solenoid is not always accessible. You can however bridge the connections on the solenoid to activate it which is the usual test of whether the problem is at the starter switch. You need to know whether the starter gets its negative supply through a cable or through its casing/engine block and whether that connection to the block is switched. If it is switched you would presumably need a jump lead to bypass the switch although I'm a lot more familiar with car systems which virtually always use a common ground.
Richard
lw395
Well-Known Member
Firstly I would check the batteries.
When your engine is cranking a bit slowly, what is the battery voltage?
13.2V is low for alternator.
12.4 is not great for a well charged battery that hasn't rested for long.
It is always best to check and double check that the battery is well charged and in good order before even thinking about anything else.
A backstreet garage or tyre shop ought to be able to test it with a simple tester that draws a heavy current and checks the voltage.
If you don't have power on the pontoon, you probably want to take the battery home for a proper charge anyway, unless you have ample solar power.
Airscrew
Well-Known Member
Good points. Yes, when I go back to the boat, that will be my first port of call.
To answer
The two batteries are only 9 months old, and in good health, ie they were not run down at all in those 9 momths.
12.4 was the first check on entering the boat, after 4 weeks unused. No power, solar, etc etc.
13.2 was a typo. 13.5 was the reading, immediately after engine start and cooling water check. I have not seen a higher reading in 9 months, as the batteries have only ever been lightly discharged.
I have a 'both' setting on the smartgauge. Reverting to both made no difference, still no click from the solenoid.
Anyway, I will take down my 3rd and spare battery, fully smartcharged, to be certain..
Both batteries are excessive spec. 2x 110Ah, and 1000CCA each
And as part of the check and clean all terminals, I will include the alternator.
Thanks.
Last edited:
lw395
Well-Known Member
If you are satisfied that the battery is well charged, then the next step is to watch the voltage under load.
If the battery voltage stays above 12 when you push the start button, the starter motor isn't drawing much current.
If it falls to below 8 or so, either the starter is drawing a lot of current, or the battery is dead.
Batteries do sometimes 'die young'. Take nothing for granted!
I have personally rebuilt a couple of pre-engage starter motors.
They do vary in detail.
Most can be made to start the engine with a duff solenoid, by shorting the heavy contacts at the end of the solenoid.
The dire warnings about not oiling the helix (and yes it usually is a helix, not straight splines on a pre-engage) (aka Bendix) mostly relate to cars, where the Helix lives in the bell housing and will attract fallout from the clutch if you oil it. A very light oil should be OK on a boat.
GT85 perhaps?
AFAIK, there are replacement motors available at sensible cost for most boat engines.
25 years ago a starter for a Moto Guzzi was nearly 2 weeks wages which I didn't have, so I learned to get everything working, re-face the contacts, re-bush the linkage, new brushes.... I got another 5 years out of it.
Good Luck.
If the battery voltage stays above 12 when you push the start button, the starter motor isn't drawing much current.
If it falls to below 8 or so, either the starter is drawing a lot of current, or the battery is dead.
Batteries do sometimes 'die young'. Take nothing for granted!
I have personally rebuilt a couple of pre-engage starter motors.
They do vary in detail.
Most can be made to start the engine with a duff solenoid, by shorting the heavy contacts at the end of the solenoid.
The dire warnings about not oiling the helix (and yes it usually is a helix, not straight splines on a pre-engage) (aka Bendix) mostly relate to cars, where the Helix lives in the bell housing and will attract fallout from the clutch if you oil it. A very light oil should be OK on a boat.
GT85 perhaps?
AFAIK, there are replacement motors available at sensible cost for most boat engines.
25 years ago a starter for a Moto Guzzi was nearly 2 weeks wages which I didn't have, so I learned to get everything working, re-face the contacts, re-bush the linkage, new brushes.... I got another 5 years out of it.
Good Luck.
<152587>
...
The fact that when invoking the start circuit leads to loss of electricity on that circuit alone. The op has already stated the other circuits continue to behave normally. Come on all you experienced electricians, wake up and smell the coffee instead of steering the op red herrings to further confuse the situation.
lw395
Well-Known Member
But are the 'other circuits' on one of the other batteries?
Airscrew
Well-Known Member
All, TE, I so appreciate your help sofar.
Heading down to the boat today to investigate.
Armed with fully charges spare, and lengths of wire and crocclips.
And I have spent some time this week going through the 'Tony Brooks' website, as recommended reading in this and other threads.
Brief recap.
Engine Battery is healthy. Engine normally starts easily and predictably. Key turn produces NO CLICK or NOISE AT ALL, and the engine panel lights and temp gauge go out and drop to zero.
BUT, Can anyone (TE??) help clarify this section, as above and here.
<<<
With the multimeter set to 12volts connect one end to the probe at the supply end and the other probe to the terminal at the engine panel if when the start circuit is invoked the voltage reading on the meter should be virtually zero. Do this on both cables(+ and -) If the meter reads any voltage at all subtract the indicated figure from supply voltage to calculate voltage drop.
>>>
Which terminals are we talking about here?
Are we referring to the back of the switch panel?
From the workshop manual diagram, on the back of the key/switch, I am expecting to see pin 30 from +ve, pin 50 to the solenoid.
So, per the instruction from TE, am I looking to check for the drop from Batt+ve to pin30,and then Batt+ve to pin50, both with the key turned.
Is this correct??
And the big one.
In my mind right now, I am not clear how to deduce wether the problem is in the wiring, the switch (maybe a short?), or the solenoid?
I will see any responses today whilst on the boat.
Any help to further clarify on this would be really great.
Thanks massively.
RichardS
N/A
It's not too difficult to test the starter solenoid if you can access the terminals.
There should be one small wire connected to a terminal on the back of the solenoid which is the connection to the starter switch.
There should also be a large cable, probably red, connected to a large terminal on the solenoid which goes to the battery positive. There may also be a second accessible large terminal on the solenoid but this will be an "internal" connection to the starter motor itself.
If you bridge the small terminal on the solenoid across to the large terminal +ve terminal with a metal tool or a jump lead there should be a spark and the solenoid should click loudly and the motor should spin for a split second. Just touch the two terminals together as there's no need to hold it on. If you get the clicking and spinning then the starter switch or its wiring is faulty. If there's a loud click but no spinning motor then the solenoid is probably OK and the problem is with the motor.
If nothing happens it could be that the negative to your solenoid/motor assembly is also switched. The way to bypass this is to connect a jump lead between the battery negative terminal and either the body of the starter motor assembly or, if it exists, a large, probably black, terminal on the starter motor which connects to the battery negative via a relay. Then try the same bridging test again and see above for the diagnosis.
You can trace these same circuit paths with a voltmeter if you want to re-assure yourself that you are identifying the correct cables before you do the bridging.
Richard
There should be one small wire connected to a terminal on the back of the solenoid which is the connection to the starter switch.
There should also be a large cable, probably red, connected to a large terminal on the solenoid which goes to the battery positive. There may also be a second accessible large terminal on the solenoid but this will be an "internal" connection to the starter motor itself.
If you bridge the small terminal on the solenoid across to the large terminal +ve terminal with a metal tool or a jump lead there should be a spark and the solenoid should click loudly and the motor should spin for a split second. Just touch the two terminals together as there's no need to hold it on. If you get the clicking and spinning then the starter switch or its wiring is faulty. If there's a loud click but no spinning motor then the solenoid is probably OK and the problem is with the motor.
If nothing happens it could be that the negative to your solenoid/motor assembly is also switched. The way to bypass this is to connect a jump lead between the battery negative terminal and either the body of the starter motor assembly or, if it exists, a large, probably black, terminal on the starter motor which connects to the battery negative via a relay. Then try the same bridging test again and see above for the diagnosis.
You can trace these same circuit paths with a voltmeter if you want to re-assure yourself that you are identifying the correct cables before you do the bridging.
Richard
Last edited:
<152587>
...
Exactly that, between the pins and pos. As regards the "big one" if the fault is in the wiring the tests will show it up. the switch will be proven by the test between pins. if the solenoid is at fault this will be apparent when you have completed the test. Do not forget that leccy is a 2 way track, test the neg side as well. pm sent