Engine How does my solenoid work? Unable to start.

[Fish]

I worked at a Scag dealer for a while. And as far as testing relays or that module, I originally sat on hold with the Scag techs for an hour, only to get some 24 year old kid fresh out of school, that actually has never worked on anything, going through a stupid troubleshooting chart, saying to put your test leads here, read the resistance, test here, etc, etc,,,

When you did all of that bull, he may tell you part #x is likely faulty, so replace it. If not, then try this:.............. After going through all of this bullchit, the machine still
won't crank, so you get frustrated and go grab that frigging module off of the self, plug it in, and the mower starts!!!!!!

Then your next problem is now to try and justify your wasting a hour or two on the phone somewhere so you don't get fired!!!!!! Bill the customer????


The problem with a lot of folks here is that they have no experience in the real world. A tech on the phone is not earning the dealer anything, and the dealer don't like that!!!!!

Same with warranty!!!! If the tech is on the phone for hours, no one makes money, and the dealer blames the tech!!!!!

As far as taking a commercial mower to a Scag dealer to swap out parts?????? Will not happen in any universe!!!!!

Just my take on things......

 

[Fish]

Yeah, the techs at a big dealership are always on the clock to earn that big dollar!!!! The last big dealership I worked at, I got in trouble for performance/dollar amounts.

Off course I was under the gun for being the Stihl/2-cycle guy

If a customer came in with anything out of the ordinary, it seemed to fall on my bench. But when I dealt with it, it subtracted from my labor dollar earnings, since I would be on the phone with some one. An electrical problem, or a warranty problem, my bench......

And all of that time on the phone with the dist. or mfg., well, tough tittae!!!!

Those techs that can only change oil on Honda pushmowers, well they deserve t be paid better!!!!!

So sneaking into the parts dept. and fixing the damn thing quick by swapping, hell yeah!!!!!!

 

[reynoldston]

Well, you keep stepping into this thread, saying that part swappers have no idea what they are doing and shouldn't be here. Have you made 1 post that might even
slightly help the original poster and his problem?

Any help with these "small potatoes"??????

You are right I haven't made one post to diagnose the OP problem. If you look at my pass post I don't do that anymore. The person doing the job has to diagnose their own work and as soon as I make any suggestions no one agrees or understand what I tell them. Then on top of that someone jumps in and arguers or gets mad at me. I have the feeling everyone knows much more then me so go at it. My attitude if they don't know what they are doing take it to a person that dose. All this forum is to me anymore is entertainment. I need wiring diagrams and service manuals myself or I am lost.

 

[Fish]

Well, we agree there!! Which is why I always request the unit's model numbers and put up parts lists and wiring schematics if at all possible.

One goes way out on a limb to try to help folks on these forums, as the crappy info from the original poster is usually most of the problem, but one also has all of the
forum's "young guns" waiting in the wings to try to prove you wrong, because you step up and try to help. And of course, you have about 5 pissed off "old guns" that
do not like newcomers......

Either way, it is a fun ego winterfest!!!!

 

[exotion]

Part swappers can be quite efficient I have boxes of parts from scrap. And about 50% of the mowers I buy and sell are generally fixed with spare parts. The free mowers I get if they aren't even worth fixing I take the engine off and chuck the rest makes for fast diagnosis

 

[Carscw]

I agree with all of you.

 

[John Ambrosia]

I don't know your electrical expertise, but you need to be very careful, as you can burn up a relay quickly if you touch the wrong terminal. I shouldn't do this, assume, but I think the relay you are talking about is like the center compression relay in this attached picture. A relay is just like a solenoid, one electrical circuit controlling another. In this case the circuit between terminals 30 and 87, is controlled by the circuit between terminals 85 and 86. If you hook a continuity meter (your VOM set on Ohms) between 30 and 87, and apply 12V across terminals 85 and 86, the switch should close and you should see continuity or 0 Ohms on the meter, indicating the relay is good. If you don't have is type of relay, don't try this test. BE CAREFUL AND DON'T ATTEMPT IF YOU DON'T FEEL CONFIDENT IN DOING THIS. If you do test the relay and it is good, then you must continue to check voltage across each of the safety switches as I posted before. I know you said you checked them for continuity, but I always check to see that voltage is going through. NEVER ASSUME ANYTHING. If everything tests good, I would take the unit to your Scag dealer and ask him if he would swap out the module, as this is one electrical part that once it leaves the store 99.99% of the time is nonreturnable.

Success!!!!!! I followed the solenoid wire to the relay where it is part of a four wire wiring harness. I unplugged the harness from the relay and checked the voltage at the harness plug-12.5 volts. Next I checked the relay. I connected a 9 volt battery to the relay across the 85-86 terminals and got the tell tale click of the switch deploying. With the switch deployed, I checked for continuity across the 30-87 terminals and found I had it. However, when I checked the resistance across this interval, I got 8 ohms. I compared this to the 30-87a terminal resistance without the battery connected and this registered 0.2 ohms. So even though I had continuity across the relay with the switch activated, the high resistance was keeping it from functioning. As a final check, I pulled the relay out of my other mower and plugged it in the bad one and the mower fired right up.

Man thanks a ton for all your help and encouragement. This tread is an excellent tutorial for how to deal with trouble shooting this problem and will hopefully help others who encounter it. Yes the thread is 6 pages long but a lot of that is musings, personal opinions, and philosophy. And there's nothing wrong with that either! Well, time to buy a new relay. Thanks again-bye.

 

[Mad Mackie]

Most if not all newer Scag machines have a relay in the cranking circuit. This relay is usually located close to the key switch. When all the safety circuits are in the correct position for engine cranking, the electronic control module will ground the relay and when the key switch is in the start position, the relay will close and allow electrical power to go to the starter solenoid which in turn will close the high amperage switch internal to it and sends battery power to the starter motor.
On the Scag website on the left side is a link to manuals. You need the model and serial number and search thru to get the correct manual for your specific machine. Toward the end of the parts portion of these manuals is a section of electrical systems and then wiring diagrams.
Most of the cranking problems on these machines can be traced to the cranking relay or the seat switch.
Mad Mackie in CT

There you go!!!!
Scag operators take note!!!!
Mad Mackie in CT
Mackie has left the building!!!

 

[Rivets]

Glad to hear of your success, I can tell by your tone that learning to electrical troubleshoot has given you a lot of confidence. Even though it took a lot longer than you thought when you started, I'm sure your feel good that you only have to replace one part. I'll bet that beer tasted real good last night.