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Tecumseh HM80 electrical question.


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#1 IamSherwood OFFLINE  

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Posted April 29, 2011 - 05:31 PM

I bench fired up this, to check if the stator was putting out properly.
Should get about 20Vac right?
I was getting 2.2Vac.
Pulled flywheel.
I'm not familiar with this engine, or electrics period for that matter.
It was in the tractor, with an external coil, and condensor.

That short red wire standing up there should be connected to ???? or not ???

Thanks

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#2 JDBrian OFFLINE  

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Posted April 29, 2011 - 06:50 PM

Hi

I just happen to have an HM80 apart right now and have the same coil assembly sitting in front of me. Mine has the built in ignition coil. The wire on mine goes to the terminal for the points and condenser. You have 1 wire attached there and I assume it goes to the external coil/condenser connection. On mine that wire is connected to the centre wire in the 3 terminal connector. The other 2 read a low resistance between them- like .4ohms. They are the lighting /battery charging coil wires. If it reads a high resistance or open something is wrong with the coil.
According to the electrical diagram in the MF 8 manual the centre wire should go to the ignition switch D terminal and the other 2 are the AC going to the regulator/rectifier. Since your electrics have been modified there may be no need for this wire? You need to draw a schematic to figure out what's up. Check all your connections to make sure they are good. Check the magnets in the flywheel to make sure they are not damaged. You can download a troubleshooting manual from the Tecumseh site for these engines.

#3 IamSherwood OFFLINE  

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Posted April 29, 2011 - 07:15 PM

Hello


"You have 1 wire attached there and I assume it goes to the external coil/condenser connection."

Yes that green goes to the external ignition coil/condensor.

I checked the AC voltage on the outer 2 terminals of that 3 terminal connector. I'll check the resistance there.


"Since your electrics have been modified there may be no need for this wire?"

Are you refering to the center wire (in the 3 wire connector) or that red one just hanging there?

Thanks

#4 JDBrian OFFLINE  

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Posted April 30, 2011 - 06:38 AM

Hello








"Since your electrics have been modified there may be no need for this wire?"

Are you refering to the center wire (in the 3 wire connector) or that red one just hanging there?

Thanks


The wire that is hanging loose is the center wire of the connector. From the diagram I have, it seems to go to the ignition switch and is grounded(connected to the switch case/tractor chassis) when the switch is off. It looks like your tractor had the internal coil at one point and was modified to have an external coil/condenser. You may no longer need this connection depending on how the ignition switch is wired.
The voltage coming out of the coil will vary with RPM's . I don't know if it would ever be 20volts AC but it should certainly be more than 2Vac. You would need at least 10-12volts AC to charge a battery. If you have a low resistance in the coil wires and if the coils are not shorted then the other ingredient you need to generate electricity is the magnetic field produced by the magnets. Check them with a screwdriver or other steel tool to make sure they are all magnetized and roughly equal in strength. When you are measuring the voltage make sure your meter is on AC and that the connections to the meter leads are clean. Some meters may not measure the AC voltage properly at low RPM's . I hope this helps. Check the manuals section on the forum to see if the Tecumseh manual is there for downloading.
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#5 IamSherwood OFFLINE  

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Posted April 30, 2011 - 07:16 AM

Thanks for clarifying that.
I'll check all that later today.




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