Yanmar starter switch

[richardabeattie]

My panel has a key to switch on the ignition and a seperate press button to start the engine. Sometimes when I press the button nothing happens at all. Then a couple more presses and the solenoid does its stuff. I have put a multimeter across the two terminals on the back of the the key switch and that has total resitance when off and zero resistance when on. I expected the same result on the two terminals on the back of the press switch. But I found that although I got zero restistance when it is pressed I got only a few milliohms resistance when not pressed. So I took the press switch out and found that when it was disconnected from everything it has full restance until pressed and then none. So I put it back into the panel and got the same low restance when not pressed. Baffled.

 

[Playtime]

I expected the same result on the two terminals on the back of the press switch. But I found that although I got zero restistance when it is pressed I got only a few milliohms resistance when not pressed.

When not pressed, I think you are measuring the resistance of the starter solenoid.

 

[ksutton]

Earlier this year I had the same problem, occasionally when pressing the starter button nothing happened. This seemed to only happen when the engine was hot and trying to restart it. Because it only happened while hot it was difficult to test or diagnose, but I suspected a drop in current from the button to the starter solenoid while wiring was hot.
I fitted a 12v relay near the starter solenoid with its coil energized from the starter button.
A separate 12v feed was connected through the relay contacts to the solenoid.

Problem fixed.

 

[Cloven]

My panel has a key to switch on the ignition and a seperate press button to start the engine. Sometimes when I press the button nothing happens at all. Then a couple more presses and the solenoid does its stuff. I have put a multimeter across the two terminals on the back of the the key switch and that has total resitance when off and zero resistance when on. I expected the same result on the two terminals on the back of the press switch. But I found that although I got zero restistance when it is pressed I got only a few milliohms resistance when not pressed. So I took the press switch out and found that when it was disconnected from everything it has full restance until pressed and then none. So I put it back into the panel and got the same low restance when not pressed. Baffled.

I have had this problem and this is worth a try before you start to pull anything apart. I spent a lot getting marine engineers looking at the solenoid & starter motor - even bought a new starter motor - and all to no avail. I then sorted the problem myself

My engine is the Yanmar 2GM20F and has a similar key & push button to yours. At the back of the switch panel the wires go into a big multiplug. On my boat this this wiring loom goes round the engine bay and into another mulitiplug just before it gets to the engine. I opened up the multiplugs, cleaned the contacts and sprayed in a little WD40 in before pushing the plug shut - problem solved for about 18 months. Problem recurred - solution the same. Now I do this at the start of each season and have no problems.

Just read ksutton's post and this could be the same problem - a voltage drop due to poor contacts - but solved in a different way?

Hope this helps

 

[Yacht Yogi]

Yanmar starter wiring

I had the same problem with the starter doing absolutely nothing when warm but if I kept trying maybe 5 or 6 presses it would suddenly work. Boat is off the water at the moment for winter maintenance. First task was to sort out a number of wiring issues.

I found an alien wire connected into the back of the start button with the original disconnected. This wire ran all the way around the engine bay and eventually, via a dodgy splice up onto the starter solenoid. The quality of the end terminals and splicing left rather a lot to be desired. I tested it all with a multimeter and determined that this was indeed the starter wire. I cleaned it and re-made the terminals and it all worked fine again.

Then I thought that maybe the original wire was just suffering from bad connections too. So I set off to trace it with a multimeter to establish at which point it went dead. For dead it surely was. I found a plug break on top of the engine, tucked in behind the air inlet spout and just below the cooling water filter thing mounted high up on the side of the engine compartment. Plenty of corrosion in evidence here. I dismantled the connector and crimped a splice to join the starter wire. I then cleaned all the ring terminals. So now that works just like it was supposed to.

I have disconnected the alien wire but left it run through the boat in case I ever feel the need to use it again.

So the message is that a damp and salty engine bay is no place for electrical connectors. You are going to get damp and corrosion on them. Cleaning and protecting the electrical junctions and terminals will just have to be a part of your routine maintenance.

 

[misterg]

The Yanmar wiring loom (1GMxx & 2GMxx) has an in-line fuse holder hidden in it (look for a bulge somewhere near the alternator). This corrodes and causes exactly these symptoms. The fuse only supplies the instrument panel and starter solenoid.

It is item 7 on the Yanmar wiring diagram.

(Yacht Yogi - I think you found the remains of the fuse holder!)

Andy

Edit: This wire should be fuse protected - it is fed directly from the alternator (& hence battery). The Yanmar diagram shows the fuse as 30A.

 

[richardabeattie]

Many thanks - I'll ckeck the multi plugs and fuse

 

[bikedaft]

check your battery terminals also (apologies if its buried in the answers above)

(just had the same problem on our yanmar)

 

[eagleswing]

add a momentary switch ?

on a lot of yanmars the start panel is in the cockpit and the hot feed goes up to the panel thru the key switch, then pressing the start button sends the volts down to the starter solenoid. 1st thing i'd check is whether the voltage available at the hot battery terminal is close to the volts received at the starter solenoid. if there is a big voltage drop , look for corrosion at the back of the panel , or wires broken or corroded on the solenoid. as another poster suggested, corrosion at the key switch or start button at the back of the B panel results in not enough volts getting to the starter solenoid. at yanmar school at mack boring, the chief mechanic suggested you could add a properly fused 'momentary' start switch near the engine start battery/engine compartment to supply voltage directly from the engine start battery to the starter solenoid, thus bypassing the key switch/start button wiring to and from the cockpit.(and its voltage drop..) this switch is useful for an emergency start or when you wan to turn over the engine momentarily from the engine bay , without running up to the cockpit .. (but NB the engine instruments , oil pressure, temp gauge etc wont be energized if you do use this momentary switch bypass to start it... )

 

[pissativlypossed]

My panel has a key to switch on the ignition and a seperate press button to start the engine. Sometimes when I press the button nothing happens at all. Then a couple more presses and the solenoid does its stuff. I have put a multimeter across the two terminals on the back of the the key switch and that has total resitance when off and zero resistance when on. I expected the same result on the two terminals on the back of the press switch. But I found that although I got zero restistance when it is pressed I got only a few milliohms resistance when not pressed. So I took the press switch out and found that when it was disconnected from everything it has full restance until pressed and then none. So I put it back into the panel and got the same low restance when not pressed. Baffled.

We had a similar problem with our new boat, the engine is a 2010 4JH5E, the starter switch would only work intermittently, a new switch was fitted under warranty (the fault being recognised by Yanmar)

 

[blackbeard]

For some time I've had this problem when trying to start my 1GM. Sometimes it starts instantly and at other times several starter button presses are needed, although it always starts eventually.
Typically there is a noticeable dimming of the oil pressure / charge lights on the panel, and an audible click from the solenoid, and not a lot else.

I have tried pretty well everything - cleaning up the obvious contacts and terminals, checking earth connection, getting the starter motor looked at, changing the solenoid, opening up the unopenable plug connection, cleaning up the 30 A fuse and holder (there are 2 fuses, incidentally, one in use and one spare), checking the resistance of the starter push button and the key switch (the key switch can't be opened, I opened it up and cleaned and reassembled - if you try this watch out for springs springing and balls rolling).

On each occasion it functioned perfectly for a few weeks and then reverted to old habits. I will keep trying.

Thanks to everyone who has posted on this thread. Now I know that I am not alone.

 

[Cariadco]

The engine will start...!

on a lot of yanmars the start panel is in the cockpit and the hot feed goes up to the panel thru the key switch, then pressing the start button sends the volts down to the starter solenoid. 1st thing i'd check is whether the voltage available at the hot battery terminal is close to the volts received at the starter solenoid. if there is a big voltage drop , look for corrosion at the back of the panel , or wires broken or corroded on the solenoid. as another poster suggested, corrosion at the key switch or start button at the back of the B panel results in not enough volts getting to the starter solenoid. at yanmar school at mack boring, the chief mechanic suggested you could add a properly fused 'momentary' start switch near the engine start battery/engine compartment to supply voltage directly from the engine start battery to the starter solenoid, thus bypassing the key switch/start button wiring to and from the cockpit.(and its voltage drop..) this switch is useful for an emergency start or when you wan to turn over the engine momentarily from the engine bay , without running up to the cockpit .. (but NB the engine instruments , oil pressure, temp gauge etc wont be energized if you do use this momentary switch bypass to start it... )

Good idea except for one thing. The engine will start if it's cranked like this, as the fuel solenoid will be de-energised and so allowing fuel into the pump. Also, the stop switch, up in the instrument panel, will need the ignition switched on, for it to work, to energise the the solenoid and so stop the fuel supply and stop the engine.

 

[alan]

I am not sure which Yanmar you have ..... but will post this anyway as it may help! I have a 3YM30 and had similar symptoms for a couple of years; every time I cleaned something or touched the wiring the problem would go away for a few weeks or even a month or so, and then for no apparent reason return!!
In the end I was talking to a charter company mechanic whilst I was on holiday (in Procida) and he showed me a relay (black round job) situated on the rear of the engine and not obviously anything to do with starting; however on looking carefully at the wiring diagram this relay was shown. This mechanic very kindly sold me a spare one for list price (there was no Yanmar agents near the port where I was) and I set about fitting it. As I was separating out the wiring from the cable tie one of the wires to this relay dropped off!!!!!! So, I remade this connection and no problem since then; I kept the spare relay just in case. Apparently, Yanmars have had problems with these relays fgailing closed and this cause the starter motor to be permanently engaged and burns out the motor........ very expensive!!!!

Anyway, just in case your engine has another relay which you do not know about!!!
Alan.

 

[Stu Jackson]

Multiplug connectors are usually used for trailer lights. We have found them on the factory wiring connections for all of our boats. They are a fire hazard when they bleed through. I urge you to remove them and hard wire the connections. Your engine will start better, too.

 

[vyv_cox]

the chief mechanic suggested you could add a properly fused 'momentary' start switch near the engine start battery/engine compartment to supply voltage directly from the engine start battery to the starter solenoid, thus bypassing the key switch/start button wiring to and from the cockpit.(and its voltage drop..)

This situation will be well known to owners of air-cooled VW vans. The length of the connections from the battery in the rear to the starter switch forward and back to the engine in the rear leads to severe loss of volts at the starter. The emergency dodge is to short the starter connection and the main battery lead on the solenoid with a screwdriver, which bypasses the starter switch. Having done this a couple of times, usually in the rain and with heavy traffic passing close to my feet as I lay under the van, I eventually led a wire from the starter connection on the solenoid into the engine compartment, where I could touch it to the battery terminal on the few occasions that the starter would not turn over.

Later still I ran dedicated wires to a press-button on the dashboard. A relay would have been better but the buttons were very cheap.

 

[stewartkinsman]

Yanmar Starter Problem.

I have read this whole thread with interest as I spent a large proportion of my summer sailing season trying to rectify identical, intermittent problems with my Yanmar 4JH-DTE(BENETEAU 44CC). I suspect the previous owner had similar problems, as there have been some wiring alterations. Several times, I thought I had rectified the problem(including, unnecessarily, changing the starter battery) only for it to return. It does seem that improving the conductivity of the circuit(cleaning contacts/terminals, new battery, even fiddling with the wiring, or allowing the engine to cool down) has a beneficial effect, albeit only temporarily. Thanks to all the contributors to this thread, I will now return to Turkey in the Spring armed with a whole raft of new ideas!