Scag Tiger Cat - no start - fuel cut off solenoid?

bjaspud

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
I have a 8 year old Tiger Cat with a 26hp Kohler and a no start condition. For the past year or so I've had an intermittent start problem where I'd have to turn the ignition key multiple times before the mower would 'catch' and attempt to crank and fire. Once the mower makes 'contact' it fires up just fine. The problem is certainly electrical in nature. I was thinking it might be the ignition switch or the park switch or the seat safety switch and was about to start trouble shooting those devices until I took a closer look and discovered that when I turn the key I get a very weak 'click' sound from the fuel shut off solenoid. My question is ... does a bad fuel shut off solenoid keep a mower from cranking and attempting to start? I want to see if I'm headed down the right path. The solenoid itself is a $12 part so I've gone ahead and ordered one. I'm just looking for confirmation that it could / should be the source of my problem. What is your opinion? One last bit of info....on occasion, after an extended running time, the mower will backfire upon shutdown. Does that indicate a intermittent operation of the fuel shut off solenoid? Or am I totally barking up the wrong tree? Thanks in advance for your input.
 

bertsmobile1

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
IF you machine has the "Tiger Eye" hour meter, that is most likely where the problem will lie.
If not then one of the safety switches is not making proper contact , usually the parking brake.

Computer chips are very cheap, cheaper than 10" of copper wire so in place of complicated wiring to make the safety switches do 2 different jobs the current trend is to slip a chip into the hour meter to control the consequences of various switches.
IT also means that every safety switch is a simple 2 wire switch, again cheaper .
Cranking circuit is generally
key > PTO switch > brake switch > solenoid
Some latter models also toss the seat switch in as well.
Test the solenoid by energising the trigger wire/s with some jumpers
Only one will be a power wire.
two will be a power & a ground and it does not matter which way you hook them up .
Test the wiring by checking the trigger wires for power ( one wire ) or power & ground ( two wire ) .
 

bjaspud

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
No 'tiger eye' I'm glad to say. The fuel cut off solenoid is just one wire. Can I assume the red feed wire is the positive and the body grounds through the carb / motor / chassis?
 

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bertsmobile1

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
Yes
But again this just blocks the main jet pick up passage.
So it will stop the engine from starting, but has no effect on cranking ( spinning on starter motor )
 

ILENGINE

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
The faint click from the fuel solenoid when the key is turned on sounds like it is working, but will not prevent cranking. How about providing which model of 26 hp Kohler you have. I am suspecting that the start solenoid is mounted on the starter and you are getting a distinct clunk when you hit the key, and after several clunks then the engine will start. If that is the case then you are having a problem with the starter. May require removing the starter and servicing it but that requires disassembly which I won't recommend. the other option is complete starter replacement.

Scag uses the seat switch as part of the start circuit. Could also be an issue with the brain box which is not a cheap replacement so have to rule out all other possibilities first.
 

bertsmobile1

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
Was there a chip fitted prior to the Tiger Eye ?
 

ILENGINE

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
Not sure when they started the Tiger Eye, but that ECU safety interlock module has been used at least 10-15 years.
 

bertsmobile1

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
OK, we get a different version down here
 

bjaspud

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
Here is an update. Using a multimeter I've checked the condition / operation of the park brake switch, the seat switch, and the left and right steering arm switches. Everything checks out fine. With the ignition key in the run position the cutter blade switch (yellow pull switch next to the ignition key) makes a large audible clunk when I pull it on. The clunk tells me that switch is working. Still, when I turn the key to crank the mower the only sound I get is a faint click from the fuel shut off solenoid. What is my next step? I have not done any trouble shooting in relation to the starter and the starter solenoid. How do I go about checking those items? Thanks
 

bertsmobile1

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  • / Scag Tiger Cat - no start - fuel cut off solenoid?
You start by getting a wiring diagram and posting it so we all are working from the same information.
From memory there is a cranking relay
 
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