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Blowing fuses


cheese's Avatar
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05-12-04, 01:58 AM   #1  
Blowing fuses

This thread was originally started by Chris1, but it got sent to me in a message instead of being posted in this forum. No problem Chris...I see you are a new member and are learning how to use the forum. I moved the thread here so you can benefit from advice from everyone, and members can benefit from the information provided. ---cheese
_________________________________________________________________

Please help me.. I'm desperate..

I have an older model (atleast 8+ years) riding sears craftsman mower. (says G4000 on the front)
Everytime I begin to turn the ignition - the 30 amp fuse blows.

I have bought a new ignition switch, new solenoid, new battery and cables .. and still it blows.
Next I bypassed (basically connected the wires together) on all the switches on the mower - the clutch switch, engaging switch.. all of them and still it blows the fuse. I have gone over every single wire and all of them look good and are not grounding anywhere...
Please help.. I'm about to just throw the whole mower into the ditch.

Thank you

 
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cheese's Avatar
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05-12-04, 02:01 AM   #2  
Hello Chirs!

Look at the starter. There are wires that run next to it. If they are behind it, they are pinched and causing your problem. You'll need to loosen the starter bolts and get the wire(s) out from behind it.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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05-12-04, 03:21 AM   #3  
If the above post by cheese doesn't appear to be the situation, post back with your chassis model number. This number should be located in the seat area (you may have to lift it up to see it and it should start with 917.) and with this we will be able to check your wiring schematic and help you further, if needed. Let us know what you find with the starter wiring.

 
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05-12-04, 05:26 AM   #4  
chris1
blowing fuses

Thanks Guys.. ya I'm new at this forum.
I went to Ace and bought another 3 packs of fuses and went through all of them again last night.
My wife wants the lawn mowed !
My model number is 917255561.
I read the post by Cheese, thanks so much! I will take a close look at the 2 wires going behind the starter.. should I also be concerned about them after they dissapear into the block? Where do they go - and should I take a look at that connection also?
I swear.. I have looked at every single wire and cant see any burned or grounded wires.
The whole thing is so strange.. the mower was working fine last year.. it sat over the winter and then the first time I tried to start it this year the mess started.
I will try again tonight taking a look at the 2 wires behind the starter - after I goto Ace and pay my daily 10 bucks on fuses....
Thanks.

 
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05-12-04, 10:01 AM   #5  
You said its been sittin out all winter. You may have rust and or corrosion on battery terminals and other connections. Make sure you remove and corrosion or rust on all connection and terminals. Let us know how it goes.

 
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05-12-04, 11:31 AM   #6  
I think that what I would do is rig up a test light. Get a 12 volt automotive bulb and solder a couple of wires to it and then connect the wires across the blown fuse. The bulb will then glow brightly if there is a short. Now you can work shaking the wires looking for the short. When you find the problem the bulb will go very dim or completely out. That way you can look for your short as long as you need to, you won't blow any more fuses, and you don't need to buy an ohm meter. If you find the problem, just remove the test light and replace the blown fuse with a good one and you are ready to go. Of course, you could alway get an el'cheap'o volt/ohm meter and go looking for the problem that way. I suspect that you will find a 12 volt wire, after the ignition switch, that pinched and the insulation has been broken, and is solidly connected to ground. It takes a real good dead short to quickly blow a 30a fuse.

 
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05-12-04, 03:40 PM   #7  
re: blowing fuses

Hello Chris:

I agree with Jughead--once you have cleaned all battery terminals and carefully inspected the wiring.

I have some sophisticated VOMS and test equipment but find the old 12v lightbulb trick the easiest way to go, as it much quicker than constantly looking over to read the scale on a piece of test equipment.

Good luck and let us know how it works out.

Snowman53

 
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05-13-04, 12:20 AM   #8  
I agree with the test light way of checking. I suggest the wires near the starter because it is a very common problem area.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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05-13-04, 04:57 AM   #9  
chris1
blowing fuses

10 fuses later.. the saga continues..
Thanks to everyone who has tried to help!! I appreciate it.
What I did last night was this.. as Cheese said - I checked the wires that run behind the starter and they turned out to be ok. Next I double checked all the wires once again - no pintching or shorting. I was unable to do the test bulb senario - I ran out of solder with my gun and didnt have any in the workshop.

But.. what I did was ended up just one by one disconnecting the 5 wires that lead into the ignition switch. I didnt try the red ones since they are what provide power. I tried the white one that goes to the solenoid- nothing, then tried the black wires (there are two sets of them each with two wires coupled together) One set has one of the wires that looks like it is coming from the rear of the mower and is coupled with the one that goes to the solenoid. I disconnected that- turned the key and sure enough - the starter kicked and the engine turned. BUT.. the engine turns over only about 3-4 revolutions and then the fuse blows. So now.. I'm thinking its just a bad starter ??? I tried it about 3 or 4 times thinking the engine might be flooded or who knows.. but each time the fuse blew. I ran out of fuses and gave up.
Should I just go ahead and buy a new starter??? I'm totally clueless as to what it is.

 
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05-13-04, 09:27 AM   #10  
It does sound like to me you have a bad startor. But I just want to make sure you have ruled out everything else first, because I can gurantee you that a new starter is going to cost you around 100 bucks or more. Let us know what you find.

 
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05-13-04, 04:26 PM   #11  
It almost sounds like the starter solenoid could be stuck in the closed position. If the solenoid contacts got welded and were stuck closed and the engine was on compression I could see that maybe it would cause the fuse to blow when you first turned on the key. The other thing to look at would be the starter bendix drive. It might be stuck in the out postion and the starter pinion is constantly engaging the ring gear. Try unbolting the starter from the engine and making a few more tests to see if you still blow fuses. I might be in favor of making your own "fuses" with a piece of smaller gauge wire and a couble of clips. That should keep you from wearing out your shoes going back & forth to the store buying new fuses all the time. I've resorted to such measures when you need to get to the bottom of a tough problem and are just tired of buying more fuses.

 
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05-14-04, 01:10 AM   #12  
The fuse will not blow if you have a bad starter, and it will not blow if the solenoid contacts weld closed. The fuse is not part of those circuits. Pick up a test light at an automotive parts store and check the circuits. It will be hard to find the short without testing. Another thing to check, look at the solenoid. There is a wire (possibly two) connected near the base of it. Make sure it is not bent over at the connection and touching something, or if there are two, make sure they are not touching each other. Try unplugging the two wires near the starter (red and white wires in one rectangular connector) and see if it is still shorting. In not, you have a blown diode on the charging stator wire. (another common problem).


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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05-14-04, 05:23 AM   #13  
chris1
blown fuse

Ok.... here we go.. almost have it figured out....
I left off where I did the other night.. by just disconnecting the 5 wires one by one that lead into the ignition. I got the engine to turn a few times and the fuse blows. So..after process of elimination... I finally cut all wires that run into the engine.. there 3. The two wires that go behind the starter and then one further up that is a black wire running inside the housing to what I think is the magneto - redish round item which the spark plug wire also goes into. I replaced the spark plug with a brand new one.
I ran out of fuses... and as Jughead suggested.. made my own fuses. I turned the key.. the fuse melted away but the engine turned and started and ran !
Come to find out the engine will not cut off with the key.. I have to choke the engine for it to shut off.

What do you think? Is it the magneto? I replaced the wires going into the magneto and that did not result in any change. I assume that that wire is what would allow me to shut the engine down?
Anyway.. I finally mowed the lawn - took me about 45 minutes. Thanks for all the help I really appreciate it.

 
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05-14-04, 05:39 AM   #14  
One of the wires you removed was probably the mag wire. Usually it must be grounded to get the motor to stop. If you left it disconnected when you got the engine started that's why you couldn't get the engine to stop with the key. Like Cheese said, maybe you have a shorted diode in the charging circuit, and that's the reason you are blowing fuses. One of the wires coming out of the engine should be the charging wire from the alternator and the other should be the mag wire going to the switch.

 
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