Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

Sign in to follow this  
kimneric

simplicity sunrunner won't start from ignit switch

Recommended Posts

kimneric
simplicity sunrunner 8 hp front-cut was given to us and has been working great for years. recently the mower was killing during operation and upon restart found that the igntion switch has broken, key just spun and the switch itself was cracked. replaced with the correct intek replacement switch and get absolutely no response with switch turned to on position. magneto is fine can jump from the solenoid provided the ingnition switch is in the off position. safety switches are disabled. is there a way to jumper the plug/harness that the ingnition switch plugs into (although I find it hard to believe the replacement switch would be defective)? terminals are s,l,g,b,m. just don't know how to troubleshoot this or whether the ignition switch breaking did some other damage.

Share this post


Link to post
Share on other sites
kimneric
for sure it is the correct replacement switch for the model we have, the local tractor place had the exact same switch although I ordered mine off the internet. husband threw away the old switch but the tractor place was certain I had the right switch. so why does it have to be in the off position-that's the mystery.

Share this post


Link to post
Share on other sites
rokon2813
I know nothing about sunrunners, but here's my 2 cents anyway. 1, its not impossible to get a bad new part. 2, since the mower was given to you, I assume it was not new, so it is possible some previous owner changed the switch using the wrong one and moved wires to accomodate the switch. As for the markings, s should be start (small wire to the small terminal on the solenoid) l should be lights g should be ground b should be battery power m I'm not sure The wire to the b terminal should be powered all the time if the safety switches are truly disabled, otherwise that power will come through the safety switches, unless the safety switches are wired between the key switch and the starter solenoid With a continuity tester, you could test the switch itself. you should have a connection between b and s only when the key is held in start position connection between b and l with key in on position possibly b and m also depending on what m does (I still don't know) never a connection between b and g you may also have a connection between g and the steel case of the key switch when the switch is in the off position only I'm again guessing that the engine is a briggs and stratton. the g terminal would be a wire grounding the points to turn off the engine I hope I didn't confuse too much, and I may be all wrong but this is how I would guess without having the machine in front of me. I would also have to follow each wire from the plug on the back of the key switch to see where it goes to be sure they have not been moved in the plug One more thing, the bad key switch may have blown a fuse if there is one somewhere, but even with a blown fuse it should not run jumping the solenoid with the switch in the off position. That alone tells me something is wired wrong.

Share this post


Link to post
Share on other sites
MysTiK
Do you have an install guide that shows what s,l,g,b,m connectors connect to what? And same question - are they all where they should be? Can you tell us what slgbm stand for? Did you copy the connectors configuration from the old one? I can see how it might be hard to start in the off position. :D Tedious questions, yes - looking for a clue to solve the mystery.

Share this post


Link to post
Share on other sites
kimneric
m is for magneto, no points in this system. i think i said before that my husband threw away the old broken switch so i have no basis for comparison. i mean this machine has worked so well for four years i literally never had to think about it, i did the mowing on a couple of our properties it has been the best machine ever. so it worked great before, ignition switch replaced with correct part, nothing is the same. he did say there were a couple of damaged wires up in the cowl? that he patched in and replaced but he swears he didn't swap anything he is a jet aircraft inspector i am fairly confident he didn't mess up. exactly how does this ignition work? no points, five terminals if the ignition switch were working properly which of the five terminals would activate the start? again for sure get spark if short across the solenoid terminals but ONLY if the ignition switch is in the off position [img]/club2//attach/UCD/censored1.gif[/img]!!!

Share this post


Link to post
Share on other sites
BLT
M ='s magneto. The kill wire from engine mag coil is connected there and either grounds internally off the switch or needs to feed thru the "G" terminal to a frame ground.

Share this post


Link to post
Share on other sites
kimneric
i did find the wiring diagram for this machine on this site on another thread. as far as i can tell everything goes where it should go in terms of the wiring harness. previous owner was elderly family member and kept meticulous records and would never have altereded anything, although he is dead so i cannot confirm. briggs and stratton motor, yes. literally the only thing that has changed was the ignition switch. i did buy another one from the local tractor place but if i take it out of the bag i can't return it and it appears identical to the one i purchased. i find it strange that this manufacturer has no identifying markings on their switches, just the company name. but maybe they just make one with this configuration? i truly don't want to burn another switch purchase if i don't have to. how does this thing activate the magneto through the switch to get spark? sorry for being a dummy

Share this post


Link to post
Share on other sites
timflury
The mag isn't "activated" like you mention. When you shut off the tractor, the magneto is supposed to get connected to ground to interrupt the circuit and shut the engine down. With the key in the off position, There should be continuity between the "g" and "m" terminals.

Share this post


Link to post
Share on other sites
JimDk
Kim, To add to Tim's post, magnetos make their own power to create spark at the spark plug. This is done by magnets in the flywheel passing the coil as the engine turns. Battery power should NEVER be hooked to a magneto. Your switch should control two seperate circuits. One is a simple ground to stop the engine. As Tim says" With the key in the off position, there should be continuity between the "G" & "M" terminals." The other circuit is 12 volts to the "B" terminal at all times (may be a fuse in this wire). With the key turned to the start position, 12 volts power is sent to the "S" terminal to activate the starter solenoid. A simple 12 volt test probe and a continuity tester are invaluable to check your switch.

Share this post


Link to post
Share on other sites
Ronald Hribar
IS the safety module still in place? if so next to it is a circuit breaker. Do you have 12 volts going in and out of circuit breaker. You said nothing was modified, but safties disabled. All of them? seat,pto,shift lever?

Share this post


Link to post
Share on other sites
kimneric
there is continuity between the g and m terminals with the ignition switch in the off position. with the fusible link removed from the system i do get 12v to the solenoid with the key in the start position. with the fusible link in the system, get popping sound (from time delay), heat and smell from the fusible link and erratic voltage. could it just be a bad fusible link? it really seems like there is a short or something grounding out, possibly resulting in a fire just kidding but not pleasant, definitely heating up.

Share this post


Link to post
Share on other sites
Ronald Hribar
It is not a fusible link, it is the circuit breaker as shown in the schematic. It is possible that it is bad. But it sounds like it is doing its job. I would undo the fixes to the wiring around the keyswitch. When the safeties were disabled, it is possible that the wires were cut for a reason. when the mower was running properly, did you have dash lights when it was in neutral and pto was not engaged? could you start it in gear or mower pto engaged? could you get off seat when mower was running? The answers to these questions will show you what was disconnected and what was not.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

×