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Discussion Starter #1
Hi everyone my names Michael. I am from sunny Australia.

I have just picked up a couple of really cheap Rover ranchers and one has had a partially finished Techumeh conversion.

The mechanical side of it was basically bolt on but the wiring is doing my head in.

I hooked up a battery to the starter and it fired up but I was unable to turn it off.

The techumseh engine has only got 2 wires comming from the voltage stabilizer and neither of them kill the engine when the key is switched off or when they are grounded to the body.

I have a Rover manual and it indicates that there should be 3 wires (for a briggs) from the engine. 1 yellow to the lights, 1 red to charge the battery, and the third one escapes me.

The 2 wires coming from the techumseh are red and green.

The engine is a Tehumseh VH100.

Any help would be greatly appreciated.

I look forward to getting to know all of you and to be able to draw on the wealth of info on these pages.

Cheers guys.

ps. this thread would contain pictures but photobucket is doing maintenance or something..
 

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I might be wrong, but looking at a parts diagram of the engine, I see 2 wires coming out of the coil. Might 1 go down to the carb linkage area, so that when you would push a throttle setting to "kill" it would short out the ignition? That would be easy to convert if that is the occasion.

Welcome to the forum, and please do try and get some photos up. Have fun on your visits.
 

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Discussion Starter #4 (Edited)
heres the rig itself


heres the only 2 wires I can find comming from the motor. I know one of them is a charge wire for the battery.


And heres the wiring from the mower body that would normally connect to the engine. The big fat one is for the starter (obviously) the longer green yellow one is for the lights. and the Plug with 2 wires should join to the engine.

I have tried just connecting these 2 to the 2 from the motor in various orders but I am still unable to turn it off.


on a side note, the engine will start and run fine with no wires attached at all. (except for the heavy red wire on the starter motor)

The ignition switch is grounded fine and all seems well.

I cannot for the life of me find any other wires on the engine. I am aware of the switch that is sometimes attached to the throttle plate on some mowers but it is absent in this case.

The only other wire on this engine is the one from the coil that disappears underneith the flywheel.

But it does not matter if I ground it to the engine it will still run..

And lastly there is this red stragler, but I think it was from a weed sprayer that had been fitted previously..



thanks guys any help will be greatly appreciated.
 

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Discussion Starter #6
thanks for that mate. I degreased the whole thing and the main wire from/to the coil is a bit damaged. I will investigate further.

thanks again
 

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Discussion Starter #7
I had a dig around at the wiring and I have found the green wire that I am assuming is the kill wire has a fuse type thing in it that is broken. It may be a diode or something.

Is this a must have ?

cheers
 

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I would say it is a must have especially being a solid state ignition system. Can you get a photo of the broken part and where it connects?
 

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Discussion Starter #9
I will pop the flywheel off tonight and have a look. I may be able to solder it on again. Will have to wait and see.

thanks again.
 

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Discussion Starter #10
POP the flywheel off aint that the truth. It bounced up about a foot. It dinged the stator up a little bit when it landed too. I hope it still works.

As it turns out it was this little fuse thing that is broken. Can anyone identify it so I can get me a new one?

heres a couple of pics?

 

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That looks like a wire-wound resistor, not a diode.
Ditto. Looks like a wire wound ceramic resistor. I do not see any resistors in the service manual. :confused:

I Googled and found a list of parts manuals for the VH100 based on the specification number.

Tecumseh VH100 Engine Models

I opened a few random manuals but still did not see any resistors. Might check to see if any of those specification numbers match anything on your engine.
 

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Discussion Starter #13
well as it turns out I managed to connect the only 2 wires I have access too around the wrong way after I removed above mentioned resistor. I blew a fuse now I have no spark.

As it turns out if the resistor had been there I wouldnt have cooked my coil.

I can detect some current coming from the stator.

So I reakon I broke the coil. dammit.
 

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Discussion Starter #15
does anyone know of a good way to test the coil and the stator?

I have read the online manuals but I dont really understand how it works and the measuring resistance thing with my multi meter...
 

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does anyone know of a good way to test the coil and the stator?

I have read the online manuals but I dont really understand how it works and the measuring resistance thing with my multi meter...
Well, I've been reading the manual along with you trying to figure out what makes it tick. :D Right or wrong this is my basic take on it and if anyone comes along that sees it differently by all means feel free to jump in with corrections! :)

What I normally would call the ignition coil they are calling the "ignition unit" which is the part the high voltage lead to the spark plug is connected and also apparently contains the solid state switching (electronic points). The coil (ignition generator coil) and stator (alternator) unit are one piece yet two separate windings on the flywheel. The ignition generator coil is used to generate power for the ignition module. The stator (alternator) coil is used to generate power to charge the battery and feeds voltage to the regulator and rectifier module.

(It does add to the confusion since the manual shows the setups used with 10amp and 20 amp alternator for battery charging along with setups with no alternator for battery charging.)

The coil resistance check is done on the "ignition generator coil". On units with a 10amp charging circuit, over 400 ohms is good and less then 400 ohms is bad. (Meaning it probably has a shorted winding(s) in it.) The part that bugs me here is a coil reading over 400 ohms could also be open. They should give some top end number like over 500 ohms bad etc.

On units with the 20 amp charging circuit, ignition generator coil resistance between 115-171 ohms is good.

If resistance readings are good on the "ignition generator coil" then the odds are it is the "ignition unit" that has failed. Without a special tester to power the module and trigger the solid state points to generate the pulsed high voltage output there would be no way possible to completely check this part. (Testing 20KV coils with a resistance meter using at most a 9 volt battery often proves a futile task. ;) )

The other test for shorts they are talking about I believe is only to test to see if the ignition key switch is shorted and shunting 12 volts back into the "ignition unit" shutdown lead.

Clear as mud now, right? :D
 

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Discussion Starter #17
stroke of luck good chaps..

I found a lawnmower place that had had a genuine brand spanking new coil sitting on their shelf for 25 years.

He said back when he bought them they were worth $250.

He sold it to me for a pricey sum of $60.

There is a few second handies on ebay for $200....

I couldn't thank the guy enough.

I have wired it up and shes a runner again.

I went as far as wiring in a kill button from the mag to the body so I dont have to juggle the factory wiring and risk blowing the SSI again.

If I did that again my only option would be a new mower.

One last question, from the pics and diagrams I have read the wire from the alternator (thingy) goes directly into the head light switch.

Would this facilitate the "trickle charge" for the battery that I need?

The only other wire I have is the yellow and green one thats supposed to be the kill (more like kill your SSI, in my case atleast) wire.

but she goes... I just have to come up with some kinda fuel tank and pump system for it.

I also have to make an exhaust, I am thinking something extravagant and as quite as humanly possible... why have lights if you cant mow at night because its too loud?.

I have a tube bender so the skys the limit.

thanks for the huge post mark-O-High-O
It cleared it up well for me.
The manual was so round a bout for some reason...

thanks for the warm welcome guys..

I will post some photos of my NOS SSI

Quite impressive indeed..
 

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Great to hear you have it running again! :cool:

...One last question, from the pics and diagrams I have read the wire from the alternator (thingy) goes directly into the head light switch.

Would this facilitate the "trickle charge" for the battery that I need?

The only other wire I have is the yellow and green one thats supposed to be the kill (more like kill your SSI, in my case atleast) wire. ..
Alternator thingy? You mean the rectifier/regulator box? The red wire with the fuse? Looking at the diagram the two yellows would be unregulated AC voltage. The red should be regulated 12V charging current through a fuse to the battery. What kind of voltage do you have on the wire both with the engine running and not running?

 

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Discussion Starter #19
yes I am refering to the thick red wire that comes from the stabilizer.

I dont have a spare red wire with a fuse to attach it too. I know the wire you speak of and it runs to the switch.

The only wire I have that I think I could put current into is the wire that goes to the lights.

I think this wire loops back to the ignition switch, so that might make its way back to the battery .

the red wire has current when the motors running and so does the wire that isnt the kill switch.

IDK
 

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...I think this wire loops back to the ignition switch, so that might make its way back to the battery .

the red wire has current when the motors running and so does the wire that isnt the kill switch.

IDK
Just make sure with your resistance meter that it never loops back through the switch into the kill wire in any of the switch positions. I know you don't want to revisit that issue again. :D ;)
 
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