Yanmar starter problems questions

[BobnLesley]

I'm sure I'm not the only person whose starter simply 'clicks' on occasion; I reckoned the cause was voltage drop in the long cables to the start-switches between the Solenoid's A & B terminals? When I checked for this I was surprised to discover that the worst offenders were the key & push-button switches themselves, rather than the cables.

My 'plan' to cure the problem is two-fold: First I hope to renew the switches, so question 1 is - rather than a one-turn switch and push-button, is there anything to stop me wiring in a two-position sprung switch (like a car ignition) instead. Secondly, it strikes me that rather than send the 30 amp starting-current from engine-bay to the control panel and then back again, I could put a short heavy gauge wire via a relay, between the solenoids A & B terminals and just have the cables to/from the control panel carrying that relay's energising power (a lot less amps through a small cable). Am I correct in my thinking and can you foresee any problems with the idea?

 

[Spi D]

Your suggested use is exactly what relays are designed for.

Very good idea to off-load the push-button and make it manage the controlling power for the relay only. I'd check peak current needs as 30A (@ 12 volt makes only 480 watt) sounds too low for the starter's consumption while cranking.

What engine is it?

 

[earlybird]

30A (@ 12 volt makes only 480 watt) sounds too low for the starter's consumption while cranking.

What engine is it?

I think the OP is referring to the solenoid current, not the starter motor.
A relay will overcome voltage drop. My Beta is so fitted, recommended for extended harnesses of over 4 metres.
Although fitting a relay will do no harm, except introduce slight extra complication, is it your real problem? if the relay is clicking, it suggests it's working, and the non-operation of the motor might be due to poor connections in the starter motor cabling to the battery.

 

[richardabeattie]

I had this problem with my 2GM20 and john@cutlermarine.com at Thornham Marina installed a modification which fixed it. Something in the wiring - he said it was a well known solution but don't ask me!

 

[Spi D]

Ahh. Then 30A capacity sounds plenty.

Agree on the main issue. If the relay clicks and power gets through, a starter rebuild might be coming up. A lot less expensive than a new starter, btw.

 

[pvb]

Secondly, it strikes me that rather than send the 30 amp starting-current from engine-bay to the control panel and then back again, I could put a short heavy gauge wire via a relay, between the solenoids A & B terminals and just have the cables to/from the control panel carrying that relay's energising power (a lot less amps through a small cable). Am I correct in my thinking and can you foresee any problems with the idea?

Where did you get the idea that the solenoid draws 30A? I'd be surprised if it draws more than 10A. Your problem is most likely to be the result of a faulty solenoid, or poor connections in the wiring loom, possibly as well as worn switches. It would be easier to start by cleaning all the connections in the solenoid circuit. If you need a new switch, there's no reason why you couldn't use a two-position sprung switch.

 

[grumpygit]

Where did you get the idea that the solenoid draws 30A? I'd be surprised if it draws more than 10A. Your problem is most likely to be the result of a faulty solenoid, or poor connections in the wiring loom, possibly as well as worn switches. It would be easier to start by cleaning all the connections in the solenoid circuit. If you need a new switch, there's no reason why you couldn't use a two-position sprung switch.

Volt drop could be the problem, but. The solenoid has two coils wound within it's little ole body. The first to energise is the pull in coil that is high amperage (around 30a) all be it brief. The second is the hold in coil is of very little current draw. If I was fitting a relay I would go for greater than 30 amp. One because it's border line for the pull in coil amperage and two, because if it's a bigger one will have a lot better mechanical durability.
One other thing to check is the pinion (drive gear) and armature shaft. The pinion needs to have just about full travel along the shaft before the main solenoid contacts make, so check for seizure of rust or debry.

 

[Tranona]

Where did you get the idea that the solenoid draws 30A? I'd be surprised if it draws more than 10A. Your problem is most likely to be the result of a faulty solenoid, or poor connections in the wiring loom, possibly as well as worn switches. It would be easier to start by cleaning all the connections in the solenoid circuit. If you need a new switch, there's no reason why you couldn't use a two-position sprung switch.

A known weak point for poor connections is the multipin connector in the wiring loom and the fuse , also in the loom.

 

[pvb]

Volt drop could be the problem, but. The solenoid has two coils wound within it's little ole body. The first to energise is the pull in coil that is high amperage (around 30a) all be it brief. The second is the hold in coil is of very little current draw. If I was fitting a relay I would go for greater than 30 amp. One because it's border line for the pull in coil amperage and two, because if it's a bigger one will have a lot better mechanical durability.

Fitting a relay is papering over the cracks. If a relay were needed, Yanmar would have fitted one.

 

[davidej]

Sorry if i am being stupid but isn't a solenoid just a heavy duty relay?

So fit a relay to operate a relay?

 

[pvb]

Sorry if i am being stupid but isn't a solenoid just a heavy duty relay?

Not exactly. A starter solenoid does have contacts for the starter motor current, but it also has a plunger which operates to engage the starter pinion.

 

[Jaramaz]

This is a Yanmar classic issue. And, no, it was not solved by Yanmar on the old engines. The solution is as OP proposes, a relay.
I had exactly the same problem on my 3GM30F, installed a relay close to the starter, since then NO PROBLEMS.
The key contact can easily be dismantled and cleaned. Doesn't hurt to do that, it consists of a rather massive copper plate.

/J

 

[grumpygit]

Fitting a relay is papering over the cracks. If a relay were needed, Yanmar would have fitted one.

Mmmm you may be right in what you say but I don't think Yanmar have carte blanche on being perfect. One of the main reasons may be the balance sheet. Fitting a relay would de-stress the loads of the starter circuit, as in solenoid, switch and wiring circuit.

 

[ctva]

A known weak point for poor connections is the multipin connector in the wiring loom and the fuse , also in the loom.

I had this same problem over the last few years and eventually got around to sorting it last winter. It involved nothing more than putting conductor grease (can't remember the name but I got it from Maplin as recommended on this forum) on the two multi connectors, one at the switch panel and the other at the back of the engine. No problems so far this season.

So before any expensive or Heath Robinson wiring, try that.

 

[blackbeard]

Some really good points on this thread. There have been other threads on the same issue.
If my 1GM is anything to go by, it will start eventually after several attempts, but clearly it's not an ideal situation and can be infuriating.
The "30A" arises from the 30A in-line fuse in the wiring harness, this is purely to protect the wiring and electrics. The starter motor is rated at 1 kW which suggests a starting current (allowing for some volts drop) around 100 A although I suspect it could be more to begin with. This via a separate (unfused) cable, of course.
You will see some ideas on likely trouble spots and cures in previous threads, for the moment it's enough to say that just about every electrical connection in the starting circuit is suspect! including in-line fuse and fuse holder, starter button and "ignition" keyswitch. Almost anything you do will cure the problem - for a time. Most of my suspicions hover around the keyswitch, which cannot be opened; if you open it and catch 2 springs and 2 ball bearings which fly out, clean the contacts and re-assemble, it may help. Also, when switching on, make sure key is rotated all the way.
A multimeter is your friend. With everything turned off, check resistance of keyswitch and starter button.
I really think that a relay is a counsel of desperation but I might try it one day. Shouldn't be necessary, but might be a practical solution.
If the charging/oil pressure lights dim substantially on pressing starter button, it's likely that the trouble is resistance somewhere in the starting circuit.
I am intrigued by the idea of bypassing the keyswitch in favour of an ordinary automotive switch capable of handling a reasonable current. Can't think of any reason why not.
While the solenoid or starter motor might be at fault I suspect that resistance somewhere in the starting circuit is a more likely source of the trouble, and cheaper to fix too. Incidentally it's quite cheap to get the starter motor checked out.

 

[Jaramaz]

Well, I did measured the resistanse over keyswitch and starter bottom. Before cleaning the keyswitch (yes, it can easily be opened and later on re-assembled), it was more than 1 ohm, after cleaning in the order of 0,1 ohm. Starter bottom had low resistance.
Agree that the full circuit has to be considered, wires and multipin connectors. The way to go around it is to use a relay.
Relay cost less than 3 £. A new starterswitch which includes a starter position will cost considerably more, and if made for cars it will not last.

/J

 

[Appledore]

"Incidentally it's quite cheap to get the starter motor checked out"

I had the 'clicking - not engaging - sound on my Yanmar 1 GM 10. (Yes, several earlier threads on this). In my case it WAS the starter motor, and nothing else. 2 years later the engine starts on the key/button. I had it cleaned and new brushes for £20.

 

[Topcat47]

Carp crimp terminals are a constant source of trouble. I took my harness out a couple of years ago and replaced them all with soldered terminals and a shrink wrap cover. It made quite a difference. I also replaced the Yanmar in line fuse-holder with something a little more robust. I had the starter motor and alternator "touched up" by a local auto electrician at the same time. Can't do much about the switch though...it's not first quality. Never thought to try another relay.