YM240 starting issues

/ YM240 starting issues #1  

Cjessee

New member
Joined
Jun 9, 2020
Messages
5
Tractor
Yanmar YM240
I have a YM240 that I use as a lawn mower. I am having a no crank issue. It does not even click when turning the key to the start position. If I use a jumper cable and put power to both the key switch terminal and battery positive on the starter solenoid it will crank just fine and start. Even when running and with the key in the run position I have no headlights, turn signals, or horn. Even the dummy lights do not come on now.
I do not have a shed to store my tractor inside out of the weather. I think that the ignition switch may have went bad. Asking for any advice from those of you who may have run into this problem before. I really do not want to just start throwing parts on it. I would prefer to diagnose the problem, if anyone has the knowledge and schematics to help. I would greatly appreciate any help offered. Thank you
 
/ YM240 starting issues #2  
Have you checked the integrity of your wiring? Critters seem to love building nest under the dash and wiring frequently ends up compromised.

If your battery is good, you should be able to jump terminals at the starter to get it to crank.
 
/ YM240 starting issues
  • Thread Starter
#3  
Wiring seems good. Battery is less than a year old. I will give it a good charge and see if that changes anything. Thank you
 
/ YM240 starting issues #4  
I think CP means jump the big terminals at the starter solenoid, not at the starter itself.

But it's probably the ignition switch. They are known to have a limited lifespan in the weather. I mean, look at how the switch is designed.....

They angled the opening to the weather to allow it to fill with water, but forgot to put in a drain. Plus it is stuffed with carbon steel (rust prone) springs and various different metals for the contacts and circuits in close proximity inside. If you add rain water and a bit of air pollution the darn thing is almost a battery....and if that isn't enough, it is actually hooked to a real battery. The wonder is that that the ignition switches last as long as they do.
rScotty

I have schematics if you'd rather....but if it were mine I'd check the fuses first and order an ignition switch second.
 
/ YM240 starting issues #5  
I had problems with my starter not long after buying it. YM2000 same as you 240. Finally ended up taking it to a Auto Elec. shop and they rebuilt it. Your need ****. volt meter.
 
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/ YM240 starting issues #6  
I think CP means jump the big terminals at the starter solenoid, not at the starter itself.

But it's probably the ignition switch. They are known to have a limited lifespan in the weather. I mean, look at how the switch is designed.....

They angled the opening to the weather to allow it to fill with water, but forgot to put in a drain. Plus it is stuffed with carbon steel (rust prone) springs and various different metals for the contacts and circuits in close proximity inside. If you add rain water and a bit of air pollution the darn thing is almost a battery....and if that isn't enough, it is actually hooked to a real battery. The wonder is that that the ignition switches last as long as they do.
rScotty

I have schematics if you'd rather....but if it were mine I'd check the fuses first and order an ignition switch second.

I am not a fan of the throw parts at a problem mindset. 1st it can get expensive quick. 2nd if you have either a bad connection or bad wires, throwing parts will not help and see #1.

It may well be the ignition switch, I have seen them busted apart from water freezing in them, but again I prefer to do a bit of checking personally. These machines are pretty simply although confined spaces often to work in. A few checks visually and a few more with a volt meter gives confidence.
Checking the fuses is such a routine process that I failed to mention it. Good catch rScotty!
 
/ YM240 starting issues #7  
Get a voltmeter or at least a 12v bulb in series with a wire.
Check if 12v is arriving at the 'ignition' switch.
If yes, and no 12v comes out of any of the terminals, replace the switch.
If no, trace the 12v circuit to the switch.

YM240 diagram:
31855d1104721271-1610d-volt-reg-wells-vr728-557466-yam240elec-gif
 
/ YM240 starting issues #8  
My YM240 had an unreliable ignition switch and the prior owner had botched the clutch safety switch, and replaced the starter, without improving anything. Don't do this.

After replacing the switch I tore it apart and found it packed solid with dead pillbugs.
 
/ YM240 starting issues #9  
Have you disconnected the battery cables and cleaned the battery posts and terminal ends? Corrosion can and does build up and does block the connection. It happened to me twice over the past 15 or so years. The last time I coated the battery terminals with dielectric grease and have not had a reoccurrence.
 
/ YM240 starting issues #10  
Have you disconnected the battery cables and cleaned the battery posts and terminal ends?
He said it cranks fine if he jumpers the starter solenoid. But no headlights etc. So the problem has to be no power arriving at, or going through, the ignition switch.
 
/ YM240 starting issues #11  
He said it cranks fine if he jumpers the starter solenoid. But no headlights etc. So the problem has to be no power arriving at, or going through, the ignition switch.

Or burnt contacts in the starter solenoid?
 
/ YM240 starting issues #13  
Just from a trouble shooting/diagnostic perspective, that couldn't cause 'no headlights'.

oops, I didn't see that bit of info. I agree; it's the ignition switch. Has anyone ever rebuilt their ignition switch?

rScotty
 
/ YM240 starting issues #14  
Has anyone ever rebuilt their ignition switch?
You would need one of those specialty tools used by instrument repair techs, that bends and seals a fresh replacement ring around the edge of gauges, speedometers, etc. My switch didn't look too bad inside after I scrubbed all the dead pillbugs out but there was no way (without a fresh ring and that tool) to re-seal it, or to hold the front/back halves together.
 
/ YM240 starting issues
  • Thread Starter
#15  
Thank you all for all the suggestions and assistance. I will check the ignition switch and go from there. From what I have gathered from your replies, the ignition switch sounds like the probable culprit. Does anyone know of an automotive style replacement or should I just order a switch from Hoye?
 
/ YM240 starting issues #16  
I've wondered about that tool. What does it looks like? And why doesn't anyone I know have one?
I've got as many weird tools as anyone I know, but I've never seen one & don't even know if that crimper tool has a name.

And for us curious types, how do you think that pill bugs get into the switch housing? Don't they seem a little too large to fit through the key slot?
It couldn't be as youngsters, or could it? ..... although wouldn't that require that switches are manufactured with pill bug chow inside?
 
/ YM240 starting issues #17  
Does anyone know of an automotive style replacement or should I just order a switch from Hoye?
Just get the Hoye replica. You need the spring-return 'twist left for Thermostart' feature which isn't included on an automotive switch. And you need the size, and terminal labeling, to match what's in there now. Hoye's price is as good as anyone for a quality switch.


I've wondered about that tool. What does it looks like? And why doesn't anyone I know have one?
I've got as many weird tools as anyone I know, but I've never seen one & don't even know if that crimper tool has a name.

I've seen it. A specialty instrument repair shop opened near my Jr Hi and I was fascinated to see them seal up expensive gauges after they re-calibrated them. As I recall it worked similar to can opener. An English Wheel might be the closest familiar tool. It knurled various size rings that they stocked.


And for us curious types, how do you think that pill bugs get into the switch housing? Don't they seem a little too large to fit through the key slot?
It couldn't be as youngsters, or could it? ..... although wouldn't that require that switches are manufactured with pill bug chow inside?
There was a small hole (drain?) on the back edge of the switch. Maybe the plastic innards were an attractant? Maybe, like rats, they ate newcomers and grew, when they couldn't find the way out. There must have been a swarm living under there while the tractor was abandoned for a while by a previous owner. I found several signs of dis-use. The worst sign was obviously years-old rancid fuel plus lots of minor electrical gremlins like what Cjessee is tracing now. After a month of maintenance and remedying neglect, its been reliable for 17 years now.
 
/ YM240 starting issues
  • Thread Starter
#18  
Interestingly my YM240 has a push button switch mounted on the steering column below the dash to operate the thermo start. It seems that the switch must have been an issue before I purchased it and is now getting to the point of no return. The little tractor has had a rough life apparently. When I purchased it 3 years ago for $1000, it had been shot a few times. Left rear wheel shot. Left headlight shot. Alternator and radiator were also shot. I had the radiator repaired. I replaced the alternator and installed led headlights. And I have also replaced the steering column. It shows about 960 hours on the clock. After I get the starting issue fixed, I plan to attempt to fix the lift. The lift is stuck in the up position. I have read a thread about it and will attempt to remedy it when mowing season is over
 

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