Wiring starter relay on Yanmar 2GM20F

[Cloven]

I have had a persistent problem starting my Yanmar 2GM20F and a Yanmar service centre has suggested fitting a starter relay. I have obtained the relay, a Durite 0-727-12 12v/30A and they gave me these instructions:

terminal 30 +ve power supply to relay (from starter main terminal)
terminal 87 +ve from relay to solenoid switch (replaces white wire)
terminal 86 white yanmar start wire
terminal 85 -ve (negative)

Below is a diagram of what I think is the correct wiring.

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Couple of question:

1. Does this appear to be the correct wiring?
2. Where should the relay be sited - closer to the starter motor or to the push button switch? or does it not matter - latter is easier.
3. Should I run a new +ve wires from the starter motor and solenoid to the relay or can I use the existing ones in the wiring loom? If the former, then I assume I would add a new fuse as per the diagram.

NB (I have a Blue Sea 30A Mega Fuse which I planned to use to replace the existing Yanmar one in the wiring loom anyway as it is so inaccessible)

Any advice on gratefully received.

 

[vyv_cox]

I have been experiencing problems that may well be the same as yours with my 3GM30F for several years. It was taking up to half a dozen presses of the button before the motor would turn. I suspected high resistance somewhere in the wire between the button and the starter solenoid, having experienced a very similar problem previously with VW vans. This year I investigated and found a total of four joints in the cable, some in multi-pin plugs and one or two in single barrel or spade connectors. I opened each one but found no obvious corrosion, so closed and opened each one a couple of times. This has completely solved the problem, started first time every time for the last half of the season.

 

[prv]

1. Does this appear to be the correct wiring?

Yes, I think so. The wire from the start button will be at +12v when it's pressed, and flow through the relay coil to 0v. The relay then closes, and allows heavy 12v into the solenoid. The source of that 12v doesn't need to be the starter motor, but it's a convenient point to take it from.

2. Where should the relay be sited - closer to the starter motor or to the push button switch? or does it not matter - latter is easier.

Close to the starter. That's the point of it, avoiding the solenoid current having to flow all the way up to the panel and back, losing voltage in the process.

3. Should I run a new +ve wires from the starter motor and solenoid to the relay or can I use the existing ones in the wiring loom? If the former, then I assume I would add a new fuse as per the diagram.

I'm not quite sure what the layout of the wiring loom would be - it might be possible, but simpler to just use new cable. It's only going to be short. Many would regard the fuse as optional.

Pete

 

[garvellachs]

I have been experiencing problems that may well be the same as yours with my 3GM30F for several years. It was taking up to half a dozen presses of the button before the motor would turn. I suspected high resistance somewhere in the wire between the button and the starter solenoid, having experienced a very similar problem previously with VW vans. This year I investigated and found a total of four joints in the cable, some in multi-pin plugs and one or two in single barrel or spade connectors. I opened each one but found no obvious corrosion, so closed and opened each one a couple of times. This has completely solved the problem, started first time every time for the last half of the season.

There's a link to this problem here:
http://www.tartan3500.com/uploads/3/1/1/9/3119926/starter_wiring.pdf
I don't see what the relay does to help - the solenoid is a relay in the circuit already surely? The link suggests running a new larger gauge wire parallel to the loom to improve the voltage sent to the solenoid.

 

[VicS]

I have had a persistent problem starting my Yanmar 2GM20F and a Yanmar service centre has suggested fitting a starter relay. I have obtained the relay, a Durite 0-727-12 12v/30A ..........


1. Does this appear to be the correct wiring?
.

Yes, I think so.

No . At least not as shown in the diagram

Terminal 30 should be connected to the main + terminal ( the one to which the heavy battery + connection is connected) on the solenoid

 

[xeitosaphil]

I have been experiencing problems that may well be the same as yours with my 3GM30F for several years. It was taking up to half a dozen presses of the button before the motor would turn. I suspected high resistance somewhere in the wire between the button and the starter solenoid, having experienced a very similar problem previously with VW vans. This year I investigated and found a total of four joints in the cable, some in multi-pin plugs and one or two in single barrel or spade connectors. I opened each one but found no obvious corrosion, so closed and opened each one a couple of times. This has completely solved the problem, started first time every time for the last half of the season.

This sounds like a problem I had 18 months ago now with my 2GM20,and after lots of web trawling the general idea was that the cable between ignition switch and starter solenoid was too small a CSA/ guage and the suggestion was to use a bigger guage cable cable. Can't remember what size exactly but I put in said cable and now it starts every time first time so to date has cured it.

" FOUND IT "

I saved the extracts from the article but can't remember its source. Here's the extract

" The solution: replace the 12 awg wire with a 10 awg wire from the key switch to the push button and replace the second 12 awg from push button to the starter solenoid. It was real easy and once you have all the necessary replacement parts, it takes about 15 minutes to fix ".

From the key switch there is a 10 awg wire coming in, on the other terminal there are three wires, a solid red, red with black stripe and white. The red with black stripe and solid red are for powering the fans and dash (alarm, lights and gauges). The white runs to the momentary on with another white 12 awg wire, from the second terminal, running to the starter solenoid.
I disconnected the existing wire from the wiring loom and just run a heavier gauge cable along side, and hey presto seems to have cured the problem

It's worth a go for the cost of a few feet of cable?

If you try it I would be interested to know if it works, as it seems to come up quite often with Yanmar's

Philip

 

[prv]

Terminal 30 should be connected to the main + terminal ( the one to which the heavy battery + connection is connected) on the solenoid

D'oh - you're right, of course. That's what I was thinking - the one where the wire from the battery arrives on the engine - but not what I wrote.

Pete

 

[Cloven]

No . At least not as shown in the diagram

Terminal 30 should be connected to the main + terminal ( the one to which the heavy battery + connection is connected) on the solenoid

Vic, thanks for the reply. OK, so if terminal 30 is connected as you suggest, to the main heavy battery + terminal on the solenoid, what is terminal 87 connected to? the other terminal om the solenoid?

 

[Cloven]

Thanks Philip.

Sounds like this may indeed be a solution. I had heard about this before but your extract is much more detailed. Worth giving it a go to see if it works and the additional starter solenoid may not be needed. However it only coats a few £s so no great loss.

Looking at the link posted by garvellachs (#4 above), Solution 5 seems to suggest the exact same remedy and has the advantage of pics. Looks like this may be the way to go.

Thanks all

Dave

 

[Cloven]

Hi and thanks for the link. Looks really interesting and concurs with a solution suggested in post #6 below.

Dave

 

[vyv_cox]

This sounds like a problem I had 18 months ago now with my 2GM20,and after lots of web trawling the general idea was that the cable between ignition switch and starter solenoid was too small a CSA/ guage and the suggestion was to use a bigger guage cable cable. Can't remember what size exactly but I put in said cable and now it starts every time first time so to date has cured it.

That was going to be my next move if jiggling all the plugs and sockets had no effect. Exactly what I was doing with VW vans 20 years ago.

 

[charles_reed]

I have been experiencing problems that may well be the same as yours with my 3GM30F for several years. It was taking up to half a dozen presses of the button before the motor would turn. I suspected high resistance somewhere in the wire between the button and the starter solenoid, having experienced a very similar problem previously with VW vans. This year I investigated and found a total of four joints in the cable, some in multi-pin plugs and one or two in single barrel or spade connectors. I opened each one but found no obvious corrosion, so closed and opened each one a couple of times. This has completely solved the problem, started first time every time for the last half of the season.

It's a good idea to use some contact cleaner on each of the joints.
On my 3YM the female spade connector for the exciting current has fallen off a couple of times - the result was no sound from starter or solenoid.
The first time it happened I sailed around in circles off Killini, for about 3 hours, before finding the culprit.
The problem is that the terminal is in a totally inaccessible and sight obscured position. I've now worked out a routine using two long screwdrivers, an adjustable mirror on a clamp and two LED torches.
Before some wise viewer asks why I don't replace the terminal - it's because I have to take the engine out to do so!!!

 

[VicS]

Vic, thanks for the reply. OK, so if terminal 30 is connected as you suggest, to the main heavy battery + terminal on the solenoid, what is terminal 87 connected to? the other terminal om the solenoid?

Yes the other (small) terminal. Where I deduce from the instructions the white wire from the ignition switch is currently connected.

The white wire from the key switch is then, as you correctly show, rerouted to 86.

 

[Cloven]

Yes the other (small) terminal. Where I deduce from the instructions the white wire from the ignition switch is currently connected.

The white wire from the key switch is then, as you correctly show, rerouted to 86.

Thanks again Vic. So if I understand you correctly, the wiring should be as follows:

Whilst I have said "replaces" in the diagram, I gather that the original wiring can be left in place.

As for wire size of the new wiring, I gather that something about 10AWG is to be recommended which relates to about 5mm2 or 6mm2

Does this sound right?

 

[VicS]

Thanks again Vic. So if I understand you correctly, the wiring should be as follows:

Whilst I have said "replaces" in the diagram, I gather that the original wiring can be left in place.

As for wire size of the new wiring, I gather that something about 10AWG is to be recommended which relates to about 5mm2 or 6mm2

Does this sound right?

You can use the existing white wire from the start button to 86 You might as well make the negative connection to 85 in the same size of cable ( neither need be quite as heavy as the current will be lower than it was when operating the solenoid directly but since I dont know what the relay coil current will be I cannot suggest anything else)

Id make the +ve feed to 30 and the connection between 87 and the solenoid coil the same as the white wire as it will carry the same current as the white wire does at present. Surely that is not as heavy as 10 AWG /5mm²?

 

[Cloven]

Id make the +ve feed to 30 and the connection between 87 and the solenoid coil the same as the white wire as it will carry the same current as the white wire does at present. Surely that is not as heavy as 10 AWG /5mm²?

I was suggesting the 10AWG on the basis of the link in post # 4 where the suggestion was to replace the current wiring loom with a direct feed to the solenoid but with heavier wiring. I guess if I go down the route of using the relay then a lighter wire would be possible - perhaps 4mm² or 2.5mm²?

The fuse rating is 30A. 4mm² wire is rated at 39A and 2.5mm² at 29A. Which would you suggest? (I have suggested these sizes as they are available as tinned marine wire from Furneaux Riddall)

 

[VicS]

I was suggesting the 10AWG on the basis of the link in post # 4 where the suggestion was to replace the current wiring loom with a direct feed to the solenoid but with heavier wiring. I guess if I go down the route of using the relay then a lighter wire would be possible - perhaps 4mm² or 2.5mm²?

The fuse rating is 30A. 4mm² wire is rated at 39A and 2.5mm² at 29A. Which would you suggest? (I have suggested these sizes as they are available as tinned marine wire from Furneaux Riddall)

I dont understand why the author of the article in that link does not see switching to the starter battery ( or both) for starting the engine to be a long term solution to his problem which is basically caused by trying to start the engine from a battery which a little discharged after a period of sailing. What's the point of a starter battery if its not to start the engine?

However I do agree with his logic that adding a relay, as Yamaha's Service centre have suggested to you, adds complexity, but it is a system that you will find as standard on some installations.

I'd see the alternatives, if cleaning and improving connections is not effective, as upgrading the wiring or fitting the additional relay using the exiting wiring where possible.
FWIW Volvo Penta use 1.5mm² between the ignition switch and the starter relay and 2.5mm² for the power to the relay contacts and from them to the solenoid in the 2010/40 series engines.

I would choose a fuse rating based on the wiring size rather than the other way round. VP fit a 15 amp fuse in the +ve supply to the control panel and another in the common negative.