Yanmar starter problems

[snowleopard]

When I press the starter button, there is a click from the solenoid and the panel lights dim indicating a heavy current draw but 19 times out of 20 the engine doesn't turn over. when it eventually turns it cranks vigorously and starts easily.

the problem is identical on both engines and has been getting progressively worse since new to the extent that now, after 1200 hours it's sometimes impossible to start the engine at all.

the batteries are fully charged, cleaning all the terminals in the battery circuit makes no difference at all.

has anyone met this problem or better still solved it?

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[paulrossall]

I would look at the starter motor. I had the identical problem on my Volvo car and a new starter motor fixed it. Paul

<hr width=100% size=1>" there is nothing-absolutely nothing-half so much worth doing as simply messing about in boats".

 

[William_H]

The problem common to two engines indicates that there is a problem in the wiring circuit from the battery to the starters. Is there a common isolation switch? If so try bypassing the switch by bolting the wiring terminals together. Try alternatively using car jumper start leads from battery positive to starter solenoid battery terminal and also battery negative to the engine frame.
You could also use a voltmeter (multimeter) to look for volt drop from the battery positive (try to contact the battery lead terminal itself) to the solenoid terminal. The voltage drop measured when trying to crank the engine should be only one volt or so Use a voltmeter also to check the battery voltage at the actual battery terminals when trying to crank the engine Faulty wiring or isolation switch will mean that when the engine is trying to crank (and failing) the battery voltage remains near 10 to 12 volts while the lights go very dim. Good luck will

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[John7]

I found a lose connection in the main 3 way power switch was causing problems once. Being lose it had arced and was in need of a good clean. When reassembled with contact grease went OK afterwards.



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[Gunfleet]

This happened to me and I discovered the solenoid was sticking. It was pretty easy to take apart and give a wash and brush up.

BTW if you or anyone else ever finds the solution to the Yanmar dodgy water pump vane please pass it on.

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[paulrossall]

John, I read somewhere that a dodgy batch of water pump impellors had been manufactured for Yanmar some time ago and the problem was spotted. I understood that all the faulty product was recalled from distributors but some customers either fitted, or had spare, faulty impellors. I do not think it is a problem today. I have just had the end plate off the water pump from my 2GM20 skimmed at a cost of £3 and it has made a significant difference to the amount of water being pumped.
Paul

<hr width=100% size=1>" there is nothing-absolutely nothing-half so much worth doing as simply messing about in boats".

 

[uforea]

This has to be an electrical fault as it is common to both engines.If there is a poor electrical connection it will be hot even though the bolts etc are tight. you need to check the positive connections on the solenoids aand also the negative connections on both engines. I suspect that it is the negative connections that are faulty. Just because the connections are tight does not mean that there is a good electrical connection. I assume that you are using the decompressor levers before starting, these should be used so that the starter can easily spin the engine up to max revs. when the levers are then moved to the "run pos." and the engine will then start easily. This helps ensure starter and battery life.

Good luck and let us know what you find.

Ted.

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[Gunfleet]

Thanks for that Paul. I must have bought most of 'em. I hope the latest replacement is one of the new bunch. At £15 a throw they ought to work! I replaced my end plate with a speedseal, which works well and is somewhat easier to replace, but still not that easy unless you want to go rolling around the bilge in a seaway. I sailed onto a mooring and replaced the vane.
PS Where's the boat now?
John

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[alan]

A friend of mine had the same problem and it lasted about a year until we found the culprit!! It seemed like an electrical problem but we gradually replaced the batteries, switch, starter button, wiring e.t.c.
The engine would always start if the solenoid was bi-passed, so we replaced the solenoid ............ still the same problem.
In the end it was a lever which goes from the solenoid into the starter motor and causes the pinion to engage/disengage from the fly-wheel ......... it was "consumed" at the end inside the starter motor.
Dismantle the starter motor and replace this lever - you can get them seperately from motor factors, you do not need to replace the whole starter motor!!


Alan.
Nettuno, Italy.


<hr width=100% size=1>Alan Cloke

 

[Oldhand]

Have had a very similar problem with a Yanmar starter. Eventually had the starter motor ovehauled. Although it was reported no problem found with the motor, it has operated perfectly since re-installation. I guess it doesn't take much to make them stick and the cause was removed on disassembly without it being noticed.

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[snowleopard]

further developments...

connected the house & engine batteries together and put the charger on, then tried to start with 14v showing on the voltmeter - instantaneous result. answer must be low voltage so take the engine battery to be tested - absolutely fine. so now i'm looking for losses in the circuit but every connector shines so you can see your face in it.

guess the next step is to strip a starter motor and see what's inside!

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[uforea]

Re: further developments...

Chris, as you have a Cat. where are your batteries stored. If they are in a central position they will be a long way from the starters and there could be a big volts drop.???

Ted.

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[oldharry]

The symptoms you describe fit exactly a failing starter motor. However the fact that both engines are equally affected suggest a wiring fault, or there could be a combination of both.

If the batteries are a long way from the engines, this could be the problem itself. At several hundred amps, the voltage drop along the cables - as well as through the solenoids and switchgear - can be significant. This in the longer term will cause the motors to overheat, damaging the coils and reducing their ability to turn the engines over.

There is a very simple way of checking for voltage drop: connect a voltmeter - preferably digital - to the positive battery terminal. Make sure you have a 100% sound connection to the battery terminal, i.e. not via the connector if you can avoid it as this itself may be faulty. Take the negative voltmeter lead to the POSITIVE terminal of the appliance under test, making sure you have good sound connections. Switch on, and the voltmeter reading is the voltage loss over the length of the cable in question.

Next do the same with the return path. Connect the starter motor metal casing back to the Negative on the battery via your DVM, and again switch on. Add the two readings together and you have the total wiring voltage drop.

You may be quite surprised just how big the drop is! Starter motors are designed to run at around 8 - 9 volts on load. Anything much below 7 volts will increase the current draw on the battery - possibly exceeding its capacity and damaging the plates, and will certainly too heavy for the motor windings, causing overheating and further damage. This ends up with a catch 22 situation where the current required to operate the motor is causing damage all round - resulting in a higher and higher demand for current.....

If one side of the feed / return circuit clearly has a large voltage drop, then this suggests a faulty component or connection, and it is simply a matter of probing each connection under load to find the fault. It is important to take readings at working load, as faults rarely show up with the thousandth or so of an amp required to work the meter!

Note that if you have to extend the DVM probe leads, make sure you do so with good quality wire, and good firm contacts.

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[snowleopard]

Re: further developments...

cranking batteries are in the engine comartments, total cable run a little over a metre. there are no common components so whatever is deteriorating is doing so equally on both sides. definitely think i've got to bite the bullet & strip one of the starters down.

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[tome]

Re: further developments...

I'd take Oldharry's advice before stripping starters. The fact that it is happening on both engines should give a clue, and I'd bet it's a poor common return connection or switch.

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[snowleopard]

Re: further developments...

no, there is absolutely nothing shared between the two engines. it has to be something that has deteriorated at an equal rate on both sides.

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[Jools_of_Top_Cat]

Re: further developments...

have you tried starting it by putting an old spanner across the solenoid.

This will at least negate the wiring and starter buttons?

<hr width=100% size=1>J

<A target="_blank" HREF=http://www.topcatsail.co.uk>

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[snowleopard]

Re: further developments...

no dice there i'm afraid - it's a pre-engaged starter so the solenoid engages the pinion as well as switching the current to the motor. a short with a spanner wouldn't move the pinion.

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[uforea]

Re: further developments...

You are quite right about the spanner across the starter terminals. You need to connect the main batt. cable on the starter to a small terminal on the solenoid which will either be a spade fitting or a threaded stud which takes an 8mm spanner. This will bypass the wiring from the switch on your panel and energise the solenoid directly.

Ted.

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[floatything]

Re: further developments...

Hi Chris - just a thought - could a fault in just one starter motor cause a voltage drop which then also affects the other. Perhaps you could try disconnecting / bypassing one starter, and see if the other works OK on its own, then do it the other way round.

Best regards

Chris (nearly ready Floatything)

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