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

I've learned that the green and black wire running to the interlock module is indeed for the starting circuit. I also must reiterate that when my mower dies that i have spark and coil voltage when immediately testing during cranking. This is whether it starts or doesn't so i'm narrowing it down to being more of a fuel issue. I did replace the fuel pump, filter and removed the fuel cut-off solenoid in the base of the carb bowl (although this worked 30x in a row when bench testing with 12 volts) . I'll continue to keep my eyes peeled for any issues. Mt father will cut this week. If i can get through 2-3 cuts without any dieing issues I will assume it to be repaired. If not I will continue to scratch my head.
 
The relay has an electromagnetic coil which when energized closes a switch in the relay sending battery positive power to the starter solenoid. The green with black stripe wire is the grounding wire for the electromagnetic coil in the relay. When all the safety circuit parameters are met in the interlock module, then this module will complete the ground for the start relay and allow cranking of the engine. Conversely, if any of the safety circuit parameters which are in place for operation of the machine with mower deck turning are interrupted, the next sequence of the interlock module is to shut the engine down even with the key switch still in the on position. The first switch in this sequence is the seat switch. The safety system on this machine, while working thru the interlock module, is multi functional by either preventing starting of the engine or the mower deck, or shutting down the engine if any safety circuit has been compromised during full operation.
Before the electronic interlock module was used, many machines had 3 or 4 relays and all the necessary wiring to accomplish the same type of safety features. The incorporation of the interlock module greatly reduced the number of relays, connectors and wiring needed, and at the same time allowed another or more safety features to be put into the electrical system. I have serviced older machines that had 4 and 5 relays and rather than spend the time troubleshooting each relay, I would just replace all of them which usually solved the electrical problem. Most machines had several different types of relays, so no one relay would do the job. I would do this one relay at a time which helped me learn the systems and decide which relays that I need to stock for diagnostic purposes. Some of the lighting kits for these machines also use a relay so the high amperage needed for the lights isn't taken from the key switch but thru a relay.
I'm going to give you a quiz on this post!!!! HaHa!!!:laughing:
Mad Mackie in CT:biggrin::smile:
 
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If you downloaded the colored wiring diagram, notice the white wire. It comes from the engine ignition harness primary side of the coils, thru the engine harness adapter and splits. One side goes to the electronic interlock module and the other side goes to the magneto side of the key switch. Most engines make spark just by cranking the engine, so the primary side of the coil needs to be grounded in order to shut down the engine. This happens either in the key switch or in the interlock module when the running parameters of the safety circuitry are compromised.
On twin cylinder engines, the harness going to the primary side of the ignition coils is a Y and has a diode in each leg of the Y. These diodes are installed there to stop the coils from backfeeding each other and preventing electrically shutting down of the engine. The Briggs parts manual uses the term, "armature, magneto", to identify the ignition coil.
Mad Mackie in CT
 
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Mr. MACKIE.... Once again I appreciate your past insight to my starter relay issue. Now that I can start and run the mower I can continue to troubleshoot my intermittent dieing issue. My father cut today and it died 4-5 times. He stated there was fuel in the clearview filter. I have checked for spark with a spark tester probe that tests for spark while the plug is still in the cylinder under normal compression. it also senses voltage coming from the coil. That being said, it always has spark and voltage present upon cranking during a restart just after dieing. I have replaced the fuel lines, fuel pump, cleaned the carb, removed the carb over flow solenoid, cleaned fuel pump vent and blew air tthrough gas cap vents.
It dies using either tank. However once it dies if I pull the fuel pump discharge hose off and turn the engine over and pump fuel out of the pump and then reinstall the fuel pump discharge hose THE ENGINE WILL THEN START and RUN for quite some time until it does again and I have to repeat the fuel pump discharge line removal steps... it's almost as if it is vaporlocking.. however the mower hasn't been changed whatsoever from stock form nor have any aftermarket parts been used other than a fuel filter...it dies in hot and cooler weather. The mower is an 04 with 540 huurs.

ANY IDEAS ON THIS ONE???
 
At this point in time I have few suggestions and here they are;
The fuel flow in fuel filters is directional, usually there is some indication on the filter as to the direction of flow.
Check the vents in the fuel caps, make sure that they are venting.
Do any fuel hoses run close to a hot part of the engine?
Fuel pumps work on pulses of pressure from the crankcase, is the pulse hose OK and installed correctly?
When the machine is in the full operating condition, brake off, levers in, deck running, the seat switch is the main safety item. I have replaced many seat switches over the years.
Electrical problems appear as a fuel problem and vice versa.
While operating the machine and it wants to die, quickly pull in some choke to see if this carries over and keeps the engine from stopping.
Did you cut the old fuel hoses off with a knife and possibly scratch the hose fittings? Air can leak thru the scratches and the fuel pump can loose suction.
Run a temporary fuel hose directly from one fuel tank to the engine for diagnostic purposes. I have replaced several fuel selector valves over the years, but not many. Some have O rings in them and can deteriorate in time and exposure to ethanol fuel.
Mad Mackie in CT:biggrin::smile:
 
Mad Mackie said:
At this point in time I have few suggestions and here they are;
The fuel flow in fuel filters is directional, usually there is some indication on the filter as to the direction of flow.
Check the vents in the fuel caps, make sure that they are venting.
Do any fuel hoses run close to a hot part of the engine?
Fuel pumps work on pulses of pressure from the crankcase, is the pulse hose OK and installed correctly?
When the machine is in the full operating condition, brake off, levers in, deck running, the seat switch is the main safety item. I have replaced many seat switches over the years.
Electrical problems appear as a fuel problem and vice versa.
While operating the machine and it wants to die, quickly pull in some choke to see if this carries over and keeps the engine from stopping.
Did you cut the old fuel hoses off with a knife and possibly scratch the hose fittings? Air can leak thru the scratches and the fuel pump can loose suction.
Run a temporary fuel hose directly from one fuel tank to the engine for diagnostic purposes. I have replaced several fuel selector valves over the years, but not many. Some have O rings in them and can deteriorate in time and exposure to ethanol fuel.
Mad Mackie in CT:biggrin::smile:
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I have cleaned the fuel pump hose that runs into the rocker cover. However I haven't removed the rocker cover. I assumed it just lays in side the rocker cover??? Or does it fit onto a nipple in the rocker cover??? I have thought about running a temporary fuel tank to eliminate a dirty tank. My seat switch performs great when ohmed out and tested for voltage cut out... its not glitchy at all..although I may check it again. ive blown out the fuel tank caps with compressed air.Sometimes and only sometimes does messing with the choke when stalling allow it to keep running. It will stall during cold or hot engine temps. Fuel filter is on correctly. I may che k into insulating the fuel line. Ill get back in a day or 2. Thanks.
 
I have loss of fuel too. Only seems to happen when hot. If I choke it, it will keep running for a bit. Starts right back up but dies, time varies but up to 10 times on one house. Any thoughts. HELP. I replaced fuel pump and vacuum line to pump. No change.
 
HDR said:
I have loss of fuel too. Only seems to happen when hot. If I choke it, it will keep running for a bit. Starts right back up but dies, time varies but up to 10 times on one house. Any thoughts. HELP. I replaced fuel pump and vacuum line to pump. No change.
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UPDATE: I TOOK the carb back apart. Cleaned every nook and cranny with carb cleaner and compressed air about 5 times each passage. I never found anything in the bowl or passage ways that my eye could carefully see. I then reinstalled the carb. Next I used a thin air comp. Blower placed between my fingers while covering each fuel tank filler hole to pressurize the 2 fuel lines coming from each tank while they were dismantled from the selector valve. Then thru the selector valve etc all the way to the fuel pump until all lines were proven to be clear. It seems as since ive done this I have a higher lever 8n my fuel filter. Ive made 3 cuts with absolutely no problems. One more and I will call it officially fixed!
 
rapidride2 said:
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....
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Are you kidding? I am having the same problem with my 2004 Tiger Cub. When I disconnect the "juice" wire from the solenoid and test it, I get twelve plus volts. When I reconnect it, turn the key switch to start, and check the starter side of the solenoid, I get 0 volts. Standard test. Says solenoid is bad. So I replaced the solenoid with a Kawasaki OEM for a relatively enormous sum. Same problem. So I slid the "juice" wire back a little along the spade and discovered 0 volts when the ignition at start, but still 12 plus when wire disconnected. Is there some sort of feed back mechanism back to the relay under the control panel? How could there be twelve volts and then nothing depending on whether the wire is connected? I'm not doubting because I see the symptoms. I just want to know why.
 
rapidride2 said:
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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That is one of your grounds. If relay ever looses ground, then your interlock module is faulty. Quick fix...attach a wire from battery negative and attach to green wire with black stripe and relay will function normally.
 
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