Cranking problem with Tiger Cub

Mad Mackie

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Hi Troops,
Replaced the engine on my TC 2 weeks ago but the previous cranking problem is still bugging me!!! So today I took a color coded copy of the electrical system and with the use of three digital multimeters and assorted jumper wires, I diagnosed the cranking problem to be the Interlock Module. I went on line and did a search with "scag 483029", which is the part number of the Interlock Module and I found that this module has been problematic and superseded to Scag P/N 483599. Evidentally there has been a problem with the 483029 module and it showed up when it receives all the correct cranking circuit inputs and then supposed to send voltage to the starter solenoid which in turn sends high amperage to the starter motor. This module is found on the vast majority of Scag mowers both zero turn riders and walk behind units.
So, if any of you have a machine with a cranking problem, check the part number on the grey plastic module and if it is 481808 or 483029 and you have an engine cranking problem, this module may be the problem.
The replacement module for 483029 is 483599 and is pricey, but I'm need to buy one as my machine is out of warranty with the exception of the new engine and the intermittent cranking problem is starting to "blow up my Kilt" so to speak!!!:smiley_aafz:
Mad Mackie in CT:laughing::biggrin:
 

Mad Mackie

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So, I went to my local Scag dealer and bought a new Interlock Module, installed it and the cranking problem appeared to have been taken care of, so Mad Mackie was a happy camper!!! However after a while the intermittent cranking problem reappeared!!!:mad:I went over and asked my neighbor to assist me in troubleshooting the electrical system as four hands and two somewhat electrical savvy minds are better than one!!! After a complete system checkout, we started jumpering out components one at a time from the key switch all the way thru to the starter solenoid. Under the panel with the throttle and choke levers, and keyswitch, is a relay that is part of the engine cranking circuit. We started to suspect that this relay was the problem and I had a similar relay in my parts stash, so I plugged it in and the cranking problem went away!!! Switched back to the old relay and the cranking problem returned. I have a set of Zona hobby saws and I cut the old relay open to see what was ailing it and I found that it wasn't closing the contacts every time I put power to it. Tomorrow I will go back to the Scag dealer and buy a new relay or maybe two as I like to have spare parts in stock for my working machines, of course I now have a spare Interlock Module at $109 but education costs money!!!! HaHa!!! The Scag relay has a diode installed in it, not sure why, but my stash spare was a basic relay without a diode.
So, tomorrow I wil give you all the rest of the rest of the story!!!!:laughing:
Mad Mackie in CT:laughing::biggrin:
 

Mad Mackie

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Now the rest of the story!!!
Bought a new start circuit relay, installed it and the starter solenoid clicks every time. Reconnected the cable to the starter motor, inspected all where I had been tinkering and started the engine. I put a voltmeter on the battery to check the charging system voltage and no rise in voltage. Removed the engine blower housing so I could get to the regulator wire connections, disconnected the regulator wires and checked the stator which was OK. Fortunately I still have the old engine , so I removed its regulator and installed it on the new engine. Started the engine an voltage at the battery went right up to 14.35 VDC!!! So Mad Mackie is a happy camper with the Scag Tiger Cub up to 100% again!!!:laughing:
I'll do the new engine 5 hour oil change some time today and service the entire machine.
I'm going to order two Signal Dynamics digital charging system monitor meters and install them on the Tiger Cub and my Ingersoll 4018 GT. I should order three and install the third on the Hustler X-ONE.
Mad Mackie in CT:smile::laughing::biggrin:
 

glwilliams58

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Now the rest of the story!!!
Bought a new start circuit relay, installed it and the starter solenoid clicks every time.
Mad Mackie in CT:smile::laughing::biggrin:

Mackie....thanks for all of this insight into the Interlock Module and the Relay Switch. I am curious to know if your final verdict was that the bad relay was the problem here. Did you ever try putting the old interlock module back in after you replaced the relay?

Thanks for all the help.

GW
 

Mad Mackie

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Yes I still have the original electronic control module on my TC. The cranking relay was my problem and I keep a spare in my stash.
Another situation came to my attention a while back and it is the path of the charging system output which goes thru the key switch and when in the off position, isolates the charging system from the battery which on engines from the mid 80s and older, was necessary to prevent the charging system from discharging the battery when the engine was not running.
Now on most small engines, the regulator/rectifier internally provides isolation protection and thru a fuse can be directly connected to the battery.
Scag still wires the Tiger Cat and Turf Tiger machines with the charging system output passing thru the keyswitch, but has direct wired the charging system output on the new models such as the Freedom Z and Cheetah.
Since I've rewired my Tiger Cub, the system voltage has increased some and I feel that overall, the electrical system is functioning better.
 

glwilliams58

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Yes I still have the original electronic control module on my TC. The cranking relay was my problem and I keep a spare in my stash.

Thanks for the quick reply on this old thread Mackie. I have really battled trying to get this issue resolved. The engine will start and run if I bypass the safety system.

Having tested the key switch in every position, all safety switches individually as well as at the interlock module plug, I then replaced the relay switch. I found out that I am not getting a ground coming out of the interlock module. As I understand it, the interlock module only provides a ground if all the safety systems are compliant.

I confirmed power from the key switch on the green wire to the relay switch, but I did not hear a click in the relay. I then bench tested the new relay switch and confirmed 85+86 clicks and confirmed that 87+87a connect (have continuity) on the click. This was true of the old relay switch as well, but I wanted to eliminate the diode from being the problem, so I replaced the relay with a new one.

Recognizing that I am getting no ground out of the interlock module (green/blk) to activate the relay, I pulled the green/black wire out of the module plug and ran a jumper from my negative terminal on the battery to it. My goal was just to see if the relay would click. However, somewhat to my surprise the engine started up and runs fine. Keep in mind that the interlock module is not even on the machine right now. While it was running I also confirmed on the amp meter that it is also throwing a full charge.

So, with this bit of information, having tested all the switches, all the way to to the module plug, and now confirming that the engine starts and runs without the interlock module in place, am I safe to conclude that the interlock module is faulty?

I want to order a new one if it is, but welcome your input to advise of anything else that I should check. Also, aside from the obvious safety hazards, are there any other mechanical/electrical concerns with running the motor without the safety interlock module in place?

Thanks,

GW
 
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scagman2

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So, I went to my local Scag dealer and bought a new Interlock Module, installed it and the cranking problem appeared to have been taken care of, so Mad Mackie was a happy camper!!! However after a while the intermittent cranking problem reappeared!!!:mad:I went over and asked my neighbor to assist me in troubleshooting the electrical system as four hands and two somewhat electrical savvy minds are better than one!!! After a complete system checkout, we started jumpering out components one at a time from the key switch all the way thru to the starter solenoid. Under the panel with the throttle and choke levers, and keyswitch, is a relay that is part of the engine cranking circuit. We started to suspect that this relay was the problem and I had a similar relay in my parts stash, so I plugged it in and the cranking problem went away!!! Switched back to the old relay and the cranking problem returned. I have a set of Zona hobby saws and I cut the old relay open to see what was ailing it and I found that it wasn't closing the contacts every time I put power to it. Tomorrow I will go back to the Scag dealer and buy a new relay or maybe two as I like to have spare parts in stock for my working machines, of course I now have a spare Interlock Module at $109 but education costs money!!!! HaHa!!! The Scag relay has a diode installed in it, not sure why, but my stash spare was a basic relay without a diode.
So, tomorrow I wil give you all the rest of the rest of the story!!!!:laughing:
Mad Mackie in CT:laughing::biggrin:
Hi Mackie, have cranking problems also on one of my 2003 cubs. Installed a new ignition switch, problem persists. Removed throttle panel to expose components. With key in cranking position, tested parking brake safety switch which made relay click. During this procedure the throttle panel accidentally came in contact with the tractor frame and engine cranked. Tested this several times and cranked each time. Don't know if relay has lost ground...must troubleshoot more...but already ordered another relay...so I guess will figure it out this week. The relay grounds via ground wire within harness yet engine cranks when panel touches metal ground...go figure?
 

scagman2

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Thanks for the quick reply on this old thread Mackie. I have really battled trying to get this issue resolved. The engine will start and run if I bypass the safety system.

Having tested the key switch in every position, all safety switches individually as well as at the interlock module plug, I then replaced the relay switch. I found out that I am not getting a ground coming out of the interlock module. As I understand it, the interlock module only provides a ground if all the safety systems are compliant.

I confirmed power from the key switch on the green wire to the relay switch, but I did not hear a click in the relay. I then bench tested the new relay switch and confirmed 85+86 clicks and confirmed that 87+87a connect (have continuity) on the click. This was true of the old relay switch as well, but I wanted to eliminate the diode from being the problem, so I replaced the relay with a new one.

Recognizing that I am getting no ground out of the interlock module (green/blk) to activate the relay, I pulled the green/black wire out of the module plug and ran a jumper from my negative terminal on the battery to it. My goal was just to see if the relay would click. However, somewhat to my surprise the engine started up and runs fine. Keep in mind that the interlock module is not even on the machine right now. While it was running I also confirmed on the amp meter that it is also throwing a full charge.

So, with this bit of information, having tested all the switches, all the way to to the module plug, and now confirming that the engine starts and runs without the interlock module in place, am I safe to conclude that the interlock module is faulty?

I want to order a new one if it is, but welcome your input to advise of anything else that I should check. Also, aside from the obvious safety hazards, are there any other mechanical/electrical concerns with running the motor without the safety interlock module in place?

Thanks,

GW
Would like to know in detail exactly how to bypass the safety system...would rather do without it.
 

scagman2

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Joined
May 23, 2015
Threads
12
Messages
57
Yes I still have the original electronic control module on my TC. The cranking relay was my problem and I keep a spare in my stash.
Another situation came to my attention a while back and it is the path of the charging system output which goes thru the key switch and when in the off position, isolates the charging system from the battery which on engines from the mid 80s and older, was necessary to prevent the charging system from discharging the battery when the engine was not running.
Now on most small engines, the regulator/rectifier internally provides isolation protection and thru a fuse can be directly connected to the battery.
Scag still wires the Tiger Cat and Turf Tiger machines with the charging system output passing thru the keyswitch, but has direct wired the charging system output on the new models such as the Freedom Z and Cheetah.
Since I've rewired my Tiger Cub, the system voltage has increased some and I feel that overall, the electrical system is functioning better.

Tinkered with the throttle panel again removing all connections, cleaning then re connecting and it started right up/ That seemed to have solved the problem for now...will keep you posted. Now have a spare ignition switch and relay, chances are I'll need them later.:laughing:
 
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