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And found out , no spark. I have been waiting for for this problem to happen, because of all the stuff I hear about the ignition system on these engines. So, any ideas, thoughts. I am not a good electrical guy, but understand some stuff.

Thanks for any help, Noel.
 

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What engine is in that tractor? Not familiar with MF but thought they had Tech engines.
 
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Discussion Starter · #3 ·
Hh120 Tecumseh. Cast iron engine.

Noel
 
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I have a 14 hp in my G12. Runs OK. Guess they all have a draw back one way or the other. I still like the Briggs.
 
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Do you have a copy of the service manual? There is a section in it that will take you step by step on what to check in the ignition system. It does note that you should check the ignition switch before any parts are replaced. I would also check the safety switches too. I have had problems with the ignition switch and the safety switches in the past both keeping the ignition from firing.

Good luck.
 

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Discussion Starter · #8 ·
I don't have a copy of the service manual.

Noel
 
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I had a bad wire going to the solid state ignition on an HH120 in a 69 Sears Suburban. I fixed the wire and and the tractor ran fine for a month or so. I eventually got intermittent weak spark and changed out both parts of the solid state ignition. The tractor has been fine ever since. Just check the wire that runs along the side of the block to see if it is cracked or worn through. A crack in the wire insulation can be hard to see sometimes, but it will arc and short out the ignition.
 

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Take the blower cover off, take the wire off the side of the ignition module that goes to the stator, check it with an ohm meter, put on lead on the wire you took off and the other to ground, should have 470 ohm s on a ten amp stator and 137 on a 20 amp stator. If it is showing an open circut the stator is bad, also check the wire that goes to the stator for cracks . The will Crack and arc off the cooling fins, . You may have to remove the flywheel to check it. There really is no good way to test the ignition module other than if all the other stuff is checked okay it probably is the module in which case you can fix you self with out buying the kit. Tahoe has a link that discribes the ones you can buy and the one s you can make
 

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I have had about 6 hh and oh tecumsehsk50 that people thought the ignition module was bad and it turned out to be the wire, when you check it check it good they break inside the casing too wiggle it all around with the meter on it. They break about two inches down from the terminal where it attaches to the ignition module and there break right at the clamp where they go into the stator
 

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There is also a 3 wire plug comming out of the blower housing, unplug it, that separates the engine from the tractor wiring , then check for spark, a 20 amp system has a plug with all three pins in a row. A 10 amp system has 3 pins but the middle pin is above the two others like a triangle that's how you tell the amps
 

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I don't have a copy of the service manual.
Noel
there is also a service manual on here for them it's is tecumseh techniciano hand book. But the stator test ohms are wrong don't go by them it says 400 ohms it's good for the 10 amp and 400 it's bad , I think they made a typo . And it doesn't say 137 for the 20 amp system.
 

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Discussion Starter · #17 ·
I found the manual. Thanks.

Noel
 
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Those stator resistance numbers seem very high to me. That must indicate a bad stator. In order to supply high currents the stator resistance would normally be low. Typically you would have a low reading or an open circuit for a bad stator, unless some other component is in parallel with the stator.

If that wire is such a common issue I would just replace it, unless it's difficult to do. On a 40yr old engine the wiring inside the tin has been baked enough to be pretty well done!
 

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I am not a fan of any small engine with electronic ignition. Seems the manufacturer does not make them so they can be diagnosed without tearing the engine half apart and give little correct information. Then they quit making the replacement parts. A points unit is a lot easier to work on and find out what is wrong. Adjust the points right and a new capacitor and they will usually run. Just my opinion.
 
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