I have a 07 Scag TC that keeps burning up solenoids...I get 12 volts on the ignition wire coming into the solenoid and after unhooking the feed wire to starter I get 12 volts there as well. My local dealer said there is a diode in the ignition portion of the wiring. The wiring diagram also shows a diode coming off the relay there. I don't see it though. Could I be getting backfeed through a diode that might be actually in the relay or do I just need a good heavy duty car solenoid? Perplexed...
Solenoids going bad
Lasko's Lawn Service
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I have a 07 Scag TC that keeps burning up solenoids...I get 12 volts on the ignition wire coming into the solenoid and after unhooking the feed wire to starter I get 12 volts there as well. My local dealer said there is a diode in the ignition portion of the wiring. The wiring diagram also shows a diode coming off the relay there. I don't see it though. Could I be getting backfeed through a diode that might be actually in the relay or do I just need a good heavy duty car solenoid? Perplexed...
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Dear Perplexed....... Hehe
There is no diode in the relay, Make sure the cable on the starter is clean and not rusted/corroded. Also clean and lube the starter to reduce possible excess drag, You can give a heavier duty solenoid a try as well but check the other things first......
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Man it sure looks clean....the connection that is...the starter is brand new...the new solenoid will fire the engine right up...but over the course of a couple of weeks the clicking continues and the solenoid eventually goes bad.
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Well that's what I'm going to try...I start the thing probably 4-5 times a day...
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Well I only get like 8-9 volts when I crank the engine on the ignition wire at the solenoid...but I figured that was the drop in voltage because of the draw from the starter...when I disconnect the starter feed and test there when I'm cranking the engine I get the full 12 volts...but I'm just not sure there should be that much fluctuation when I'm cranking...is 8-9 volts enough? I keep thinking no, but I'm no expert...maybe that's whats throwing the copper bar in the solenoid up and down?...
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Here's what ya do bud.
You wire in a standard cube type relay to fire the solenoid. Absolutely will cure what ails ya.
Follow along: Remove the starter switch wire at the solenoid and connect it to terminal# 86. Wire term. # 87 to ground (this will activate the relay).
Wire term. # 30 to the terminal on the solenoid that the heavy battery cable is attached to. Finally, wire term. # 87 to the solenoid terminal that you removed the starter switch wire from.
Here's how it works: When you hit the key start switch, you send 12v to the cube relay coil. The contacts close and send 12v to the solenoid.
You want to keep wires as short as possible. you can prolly just use a cable tie to secure the cube to the heavy bat. cable or any handy place.
The cube relay terminals : 86 & 87 are the coil. 30 is common. 87 is N.O. 87A is N.C.
You wire in a standard cube type relay to fire the solenoid. Absolutely will cure what ails ya.
Follow along: Remove the starter switch wire at the solenoid and connect it to terminal# 86. Wire term. # 87 to ground (this will activate the relay).
Wire term. # 30 to the terminal on the solenoid that the heavy battery cable is attached to. Finally, wire term. # 87 to the solenoid terminal that you removed the starter switch wire from.
Here's how it works: When you hit the key start switch, you send 12v to the cube relay coil. The contacts close and send 12v to the solenoid.
You want to keep wires as short as possible. you can prolly just use a cable tie to secure the cube to the heavy bat. cable or any handy place.
The cube relay terminals : 86 & 87 are the coil. 30 is common. 87 is N.O. 87A is N.C.
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Here's a link to the relay:http://www.delcity.net/store/5-Pin-Relay-with-Mounting-Bracket/p_73576
You can get em at any auto parts store.
You can get em at any auto parts store.
Here's a link to a thread in a tractor forum that explains how to do it and contains photos and diagrams. I have the link saved so when I need it I can reference it.
Hope it helps.
Starter Assist Relay Assembly and Install
Hope it helps.
Starter Assist Relay Assembly and Install
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That is the voltage drop from the starter draw and it looks too low, It should be no less than 10 volts 10.5 being even better. I'd be checking into the battery closer and possibly going to a higher cranking amp battery.
Fish...... If there's already a starter relay in the system why add a second ?
Also..... This style solenoid does not require full 12 volts just to activate the plunger.
With the added info above, IMO..... Battery voltage drop (from weak/bad battery) while starting (after engaging the plunger) is what's burning the plunger disc and post contacts up......
Nice link. Thanks!
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Yeah this relay has definitely got me interested...I'll check the battery again...thanks for the information...it definitely gives me more to play with and think about.
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Listen to Rob. He's on the right track. I should have pulled a wiring diagram for the Tiger Cub before confusing the issue.
He's right. There is already a starter relay in the circuit.
I looks like Scag put suppression diodes around all of the control coils in the circuit to protect the modules (safety and fuel management on the Briggs). That's probably what your dealer was talking about. I don't believe they are causing your issue.
Look at your battery and try a different source for a new solenoid. Purchase a quality starter solenoid. There are some real cheapies out there that don't last long.
Q
He's right. There is already a starter relay in the circuit.
I looks like Scag put suppression diodes around all of the control coils in the circuit to protect the modules (safety and fuel management on the Briggs). That's probably what your dealer was talking about. I don't believe they are causing your issue.
Look at your battery and try a different source for a new solenoid. Purchase a quality starter solenoid. There are some real cheapies out there that don't last long.
Q
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REDUNDANCY!!! Much like when ya drive a chevy, ya always need to carry a set of jumper cables with ya!
Or not. No need for a relay if it already has one!!
As was mentioned, ya need to address both positive and ground batt. cables/connections.
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I will do a load test on that battery but its only 1 year old...worth checking...I also went to NAPA for a heavier duty car solenoid but they told me that it wouldn't work because a lawnmower solenoid is internally grounded so that it functions correctly...didn't make sense to me since there is a specific ground wire on the lawnmower solenoid...????
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Tell them to stop thinking and give you what you just asked for.
Generally speaking there are 2 type of solenoids most mower use.
They all have 2 large posts for the battery in and out.
Some have a single small post for the control coil in the solenoid. Those are internally grounded.
Some have 2 small posts. One post for each side of the control coil. Some manufacturers wired the safety system into the ground side of the control coil on the solenoid.
If you have a solenoid with the extra small post and it's not used, just create a jumper and run it to ground. I doesn't matter which post you chose.
Q
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Yeah..that's what my buddy told me to tell them too! I have the last solenoid pictured...It has two large and two small...the two small posts are the ground and the ignition wire...
ML
ML
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Big Fish...the circuit does have a relay in the control panel...does this same relay act as a starter assist relay...like described above? Anyway to test that to see if its working correctly and putting the 12 volts out?
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If it wasn't putting out ample voltage the solenoid would not engage the plunger when the key is turned.
As you found out from JimQ, There's no difference in auto and mower solenoids other than auto being heavier duty, Most auto parts people are nothing but computer operators.......
Oh...... Batteries are like tires, They can be good one second and bad/flat the next......
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