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Simplicity sunstar 20 no crank


simpcataha

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simpcataha

One of my sunstar M20's has been giving me a fit.  I have a no crank situation. I have a few of these tractors, so I've been able to do a bit of part swapping to help me figure it out, but I've had no success. My solenoid always clicks when the ignition switch is turned to the start position with a butt in the operator's seat. I then have 12 volts delivered to the terminal at the starter, but no crank. I've swapped the starter with a good spare w/ no luck. The starter case has good continuity to ground. All of this leads me to confusion. I have little to no voltage drop from battery positive to starter terminal when attempting to crank. Am I missing something?

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simpcataha

I believe the battery is grounded to one of the intake manifold bolts. My starter case has good continuity to the negative post on the battery. I forgot to mention that one earlier.

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Ronald Hribar

When you measured voltage to starter solenoid 

where did you place test leads?

if you cross between the two large posts on the solenoid 

will the starter engage?

 

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SmilinSam

Two tests I do when in a no crank situation in addition to checking the voltage at the connections.

 

One is what Ron said to do above. Jumper wire from one side of the solenoid to the other ( hot side to starter side - use a heavy wire of battery cables)). If it does not crank that generally tells you that there is something wrong with the starter of starter ground.

The other test is to jump directly from the battery ( can use hot side of solenoid) to the small actuating terminal on the solenoid. If it doent crank generally either the solenoid is bad, or theres not enough voltage through the safety circuit to actuate the solenoid while turning the key.

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simpcataha

I just did another test that may or may not have told us anything.......I put a heavy weight on the seat to mimic an operator and moved the ignition switch to crank. I can hear and feel the solenoid click with my hand when energized. There is next to no voltage drop across the solenoid when energized, and also next to no loss at the cable lug on the starter when energized. The starter does not engage. The starter case has perfect continuity with the negative post on the battery............I can get the starter to engage and crank when I add an external ground cable from the case to the battery negative while the solenoid is energized.

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simpcataha

I agree, but unfortunately my starter case shows 0.00 ohms of resistance to the negative terminal of the battery. That's why I'm so confused. The negative side of my battery has good continuity to the frame, the engine, and the starter. 

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 zero resistance at the tiny voltage of an ohm meter don't mean much. Pulling enough amps to make the starter work is another story. I'd clean the ground cable at both ends.

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simpcataha

You guys are spot on. I wasn't thinking about the huge difference between the multimeter amp signal for resistance checks vs. the real amp draw of a starter. It's not fixed yet, but I'm confident it will be within the hour of me being home from work now that people put some sense into me.

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Ronald Hribar

By any chance

does your solenoid have two small terminals on it?

one for positive signal from ignition switch

the other  a ground signal

that goes thru your safeties?

 

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simpcataha

That is exactly how my solenoid is. The solenoid is definitely doing its job, so that must mean the interlock box sees all of its necessary criteria to then ground the control side of the solenoid. The solenoid always clicks, and always delivers 12 volts to the starter, but the big starter amperage can't get back to the negative side of the battery. I'm pretty sure you and Tarheel have it all figured out. As soon as I get home from work I'll be cleaning the connections on the main negative cable, and I'm nearly certain it will then crank over. I've basically made a mountain out of a mole hill by overlooking the simplest and most likely culprits in a problem like this.

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simpcataha

Big fat thanks goes out to the simplicity/12 volt experts. My small sunstar 20 fleet is now all running and ready for tractor chores. I had to cut about 2 inches out of my main negative cable to get rid of the green wire strands and crimp a new connector. It's now a runner. Thank you guys for the help. 

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Ronald Hribar

If nobody had problems .we would not need this site.

i have learned a lot here

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If the terminal you crimped on the cable has a sealed end on the bolt-hole size, put some adhesive-lined heat shrink tubing over the exposed wire part and seal it up. It'll stay nice and corrosion free for years like that.

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