2004 Scag Tiger cub 48" won't start/won't crank

rapidride2

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2004 Scag Tiger cub 48" STC48A 19KA / Kawasaki engine won't start/won't crank. It is older yet is kept indoors and has about 550 hours. This mower will now start about 1 out of every 40-50 attempts with the key. It SEEMS as if it has gotten worse. Since I've been attempting to troubleshoot it the past few days it used to start on about 2-5 turns of the ignition switch. I am just a very average shade tree mechanic.

Here is what I've checked. I have 12.8-13.0 volts at the battery. I tested the ignition switch per a you tube video? I have continuity and seemingly Checks okay (per the video?) I have 12.8v at the red battery cable at the starter and 0v at the small red wire on that same lug. I have 0volts at the green/white striped wire that is on the spade on the solenoid when it is attached. HOWEVER, With the key to "start" position when the green/white striped wire is removed from the solenoid spade I then have 12.8 volts??? When i touch the wire to the spade I have 0 volts??? Ive ohm'd out the parking brake, lever switches, and seat switch. Fuses are good as well. When turning on the key i can hear/feel the start relay clicking . I can start the mower by jumping the solenoid at the starter. I've went through the flowchart of diagnosis from the scag technical manual. It's lead me faulty wiring or connections. i have continuity and ground from the negative battery to the grounds on the engine/frame the black wire at the module interlock box, and the black wire at the ignition switch...I'm assuming these grounds are okay. I've cleaned/used dielectric grease most of the connections. I have not checked the pto switch but didn't think this was causing an issue as it has worked flawless.

It seems like its an ignition switch as it has gotten worse because i can run and park the mower and it wont start. Nothing on the mower will move and many key turns later it will then start. However the switch tests out okay. and it will switch key on power many consecutive times to the small green/white solenoid wire ONLY when it is unattached from the solenoid spade?

I really don't want to send this to the dealer only to have them guessing while racking up a huge bill. ANY HELP WOULD BE GREATLY APPRECIATED!!!!!!!
 

Mad Mackie

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Under the control panel that has the key switch is a relay that is the start circuit main control point passed the key switch. Purchase a Scag replacement for this relay as it had a diode in it. However you can use an auto parts store relay for trouble shooting. Another possibility is the seat switch, but check the relay first.
Mad Mackie in CT
 

rapidride2

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I looked at the relay. I can hear and feel the relay clicking when the key is turned to start. I've always thought that relays don't usually go bad. I do have power going to the green wire with the diode??? I will check a little further into it.
 

Mad Mackie

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Recently had the same problem with my 2008 Tiger Cub. The relay would click so I assumed that it was working, however when I had a second person assisting me, the relay turned out to be the problem. I cut the relay open and put it back on the machine and I was able to see first hand what was happening with the relay. It would click but the engine would not crank, then a tap on it would cause it to function. Another possibility is the electronic control module which compares all the safety circuit inputs and either prevents or allows engine cranking. I would replace the relay first as the module is around $100. The Scag part number for the module is 483029 which has been changed to 483599 as the modules had a high failure rate and were updated by Scag a while back. I keep one 483599 in my parts stash along with a relay 483013.
Mad Mackie in CT
 
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rapidride2

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Also, when i pull the green&white wire off of the solenoid i CONSISTENTLY have 12 volts at the solenoid wire. I suppose this tells me that the key-switch and relay are working. It's whenever i plug the green &white wire back on to its spade (or even touch the wire to the spade) i lose 12 volts. I guess this tells me I have some severe resistance somewhere else????
 

rapidride2

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Tada!!!! Thanks MadMackie... it was the starter relay... it was clicking and ticking but obviously wasnt holding in when the starter needed the extra current. At least this will allow me to maintain troubleshooting my "other" issue of intermittently dieing.... I have spark at the plugs and coils when cranking when it dies... I have replaced the fuel pump..cleaned the carburetor. I have also tested the carb fuel shut off valve in the carb bowl. It test out good but I am currently using a metric bolt in the bowl to bypass the fuel shut off valve to see if thats the problem... THANKS AGAIN....
 

Mad Mackie

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If you go to the Scag website, click on manuals, click on STC, scroll down to the Briggs powered models and download the first of the three manuals. In this manual is a colored wiring diagram that makes electrical troubleshooting much easier, you can print the wiring diagram page only. I have printed the electrical components pages along with the wiring diagram and I keep this info with my machine folder.
You have a safety circuit problem and many of the safety circuits have a dual purpose, so you need to trace this thru from a starting point. Several things you may want to check:
The seat switch is a common item and sometimes problematic.
Key switches are know to go bad.
If you machine has an electronic interlock module of either P/N 481808 or 483029 this may be a problem. They have been replaced by P/N 483599. This is a pricey component however all safety circuit inputs go to and from this module. Incorrect troubleshooting of the electrical system can damage this module.
All electrical plug connectors are suspect as they can collect dust.
Let us know how you make out with this machine.
Mad Mackie in CT:biggrin:
 

rapidride2

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If you go to the Scag website, click on manuals, click on STC, scroll down to the Briggs powered models and download the first of the three manuals. In this manual is a colored wiring diagram that makes electrical troubleshooting much easier, you can print the wiring diagram page only. I have printed the electrical components pages along with the wiring diagram and I keep this info with my machine folder.
You have a safety circuit problem and many of the safety circuits have a dual purpose, so you need to trace this thru from a starting point. Several things you may want to check:
The seat switch is a common item and sometimes problematic.
Key switches are know to go bad.
If you machine has an electronic interlock module of either P/N 481808 or 483029 this may be a problem. They have been replaced by P/N 483599. This is a pricey component however all safety circuit inputs go to and from this module. Incorrect troubleshooting of the electrical system can damage this module.
All electrical plug connectors are suspect as they can collect dust.
Let us know how you make out with this machine.
Mad Mackie in CT:biggrin:

I have downloaded the troubleshooting flow chart regarding all the operator safetys. Ill plan on running through these steps in the next few days to hopefully fix my intermittent dieing issue. I have ohmed out the lever and seat safety's but still need to check out thewires.
 

maca3731

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2004 Scag Tiger cub 48" STC48A 19KA / Kawasaki engine won't start/won't crank. It is older yet is kept indoors and has about 550 hours. This mower will now start about 1 out of every 40-50 attempts with the key. It SEEMS as if it has gotten worse. Since I've been attempting to troubleshoot it the past few days it used to start on about 2-5 turns of the ignition switch. I am just a very average shade tree mechanic.

Here is what I've checked. I have 12.8-13.0 volts at the battery. I tested the ignition switch per a you tube video? I have continuity and seemingly Checks okay (per the video?) I have 12.8v at the red battery cable at the starter and 0v at the small red wire on that same lug. I have 0volts at the green/white striped wire that is on the spade on the solenoid when it is attached. HOWEVER, With the key to "start" position when the green/white striped wire is removed from the solenoid spade I then have 12.8 volts??? When i touch the wire to the spade I have 0 volts??? Ive ohm'd out the parking brake, lever switches, and seat switch. Fuses are good as well. When turning on the key i can hear/feel the start relay clicking . I can start the mower by jumping the solenoid at the starter. I've went through the flowchart of diagnosis from the scag technical manual. It's lead me faulty wiring or connections. i have continuity and ground from the negative battery to the grounds on the engine/frame the black wire at the module interlock box, and the black wire at the ignition switch...I'm assuming these grounds are okay. I've cleaned/used dielectric grease most of the connections. I have not checked the pto switch but didn't think this was causing an issue as it has worked flawless.

It seems like its an ignition switch as it has gotten worse because i can run and park the mower and it wont start. Nothing on the mower will move and many key turns later it will then start. However the switch tests out okay. and it will switch key on power many consecutive times to the small green/white solenoid wire ONLY when it is unattached from the solenoid spade?

I really don't want to send this to the dealer only to have them guessing while racking up a huge bill. ANY HELP WOULD BE GREATLY APPRECIATED!!!!!!!

There is a relay under the ignition switch that will give trouble. The relay has a diode in it which seems to be a problem...Use another relay to trouble shoot it. I had the same problem and it fixed it. Also I would peck on the relay and it would start.
 

rapidride2

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I went and tested all of my switches except the pto switch. However i've never had any issues with the pto engaging whatsoever. Since the relay has been replaced and the machine will now start, I decided to test drive the mower with the hopes that the intermittent dieing would be fixed. So far so good. In fact I'm not sure if it's a mental thing or not but it seems to be running very smooth? I do know a green&black wire does run from the ignition relay that i replaced down to the interlock module wiring connector. At first i didn't think the start relay had anything to do with anything but the starting circuit. Now i'm not so sure??? Actually my intermittent dieing issue has been going on a long long time. Sometimes it won't die at all,, sometimes it will die 6-8 times when cutting. I need to find out more about exactly the green and black wire coming form the start relay to the module does???
 
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