a-100 no spark anymore

[russellmc301 600]

we ran it once and then parked it and started the restoration.

 

we got done and we thought we hook all the electric back up the same way. i kept cranking and then we gave up and i forgot  to turn the key off for it was on run. we sat and looked at the wiring when smoke comes out from under the engine cover.  so what could be the problem? some of the safety switches were disconnected and the wiring looked jerry ridged. but why the 1 st time and not after the restore?

 

there are 2 wires that come out from under the fly wheel that we don't know what they connect too

 

forgot something 

Edited March 17, 2016 by russellmc301

[953 nut 51,877]

The two wires coming from under the flywheel go to your voltage regulator/rectifier, you didn't have power connected to them did you? As for the no spark, presuming you have a battery powered ignition system you may have burned out the ignition coil by leaving the key on. 

Go to the manuals section and download the wiring diagram if you haven't already done so.

[russellmc301 600]

there are 2 sets and them seem to be connected 1 that comes out by the starter and a set coming out by the Magneto Armature and it ran like a queen without them hooked up but we ran it once though. the thing is it doesn't have 2 of the things you are talking about it has a Briggs & Stratton 251707 and no ignition coil or regulator/ rectifier.

 

the only thing is it might have been the magneto since that is the only thing under there.

 

i would post pic but it says they are over 2.1mb

 

we looked at all the wire diagram and labeled the wires. 

 

i'm thankful for your help 

Edited March 18, 2016 by russellmc301
forgot stuff

[953 nut 51,877]

Here is your Manual, I was thinking Kohler, don't have much Brigs background; hope the manual will help you.

 

[gwest_ca-(File Mod) 10,509]

A-100 produced in 1976 using model number 62-10BP01 and 1977 using model number 72-10BP01.

Both used the B&S 251707-0161

 

There is a wiring diagram in this 1977 tractor manual

A poor tractor parts list but all we have

Engine manuals

B&S alternator wiring

Garry

[russellmc301 600]

Thanks guys i have all that stuff, i'll look at it to see if I find anything else.

 

The bad thing to having an A-100 is that i have only found few active members with them.

 

but that makes rusty even better

Edited March 18, 2016 by russellmc301

[pfrederi 17,164]

Don't have an A series but looking at the wiring diagram the pair of wires are for the lights unregulated AC and the "charging system"  3 amp DC  (just like some Kohlers).  The third wire to the engine from the switch kills the magneto by grounding.  Disconnect it from the key switch and try starting.  (If it runs you can stop the old fashioned way screwdriver to top of the plug.)  that would indicate bad key switch.  Still no spark ...There may have been voltage on that wire and fryed the magneto.

[russellmc301 600]

My neighbor ( the one that letting me help him) called his mechanic and later tonight his friend is going to call him.

 

He is a small engine teacher at the local trade school. hopefully he steers us in the right way.

 

Thanks we check the wiring 5 times or more and we think it is the magneto, i mean it is only 50 years old 

[Save Old Iron 1,563]

On 3/18/2016 at 8:23 PM, russellmc301 said:

 

The bad thing to having an A-100 is that i have only found few active members with them.

 

 

This fact alone does not make the model more difficult to repair. This style electrical system is used in hundreds of different models of lawn tractors over the last 40 years. Your issue will be diagnosed in 10 minutes by someone who has the experience to understand how this simple system functions. One good rule of thumb, when you see smoke and don't know basic troubleshooting, reach back and open your wallet. Good luck with the vertical Onan - very pricey replacement parts. Sorry - you did mention this is a Briggs engine.

 

 

 

15 hours ago, pfrederi said:

Don't have an A series but looking at the wiring diagram the pair of wires are for the lights unregulated AC and the "charging system"  3 amp DC  (just like some Kohlers).  The third wire to the engine from the switch kills the magneto by grounding.  Disconnect it from the key switch and try starting.  (If it runs you can stop the old fashioned way screwdriver to top of the plug.)  that would indicate bad key switch.  Still no spark ...There may have been voltage on that wire and fryed the magneto.

 

 

Excellent advice. For that matter. disconnect all three wires as none are required to crank and run the engine.

 

The wire with the "bulge" in the the charge wire.

The wire leading to the magneto is the kill wire.

The reaming remaining wire is the headlight wire.

Edited March 19, 2016 by Save Old Iron

[russellmc301 600]

What is a vertical onan and reaming head light wire  and  the wire with the bulge were does that come out of. 

the engine turns over and all we need is spark to get it to go.

I seem to be good at trouble shooting but i have a lot to learn. i know the magneto is fried I, just i need to know how it got fried.

this also my first wheel horse restoration so i love help.

[Save Old Iron 1,563]

5 hours ago, russellmc301 said:

What is a vertical onan and reaming head light wire  and  the wire with the bulge were does that come out of. 

the engine turns over and all we need is spark to get it to go.

 

forget I mentioned the Onan - I have been working with another member on a different tractor with a different engine - looks like I mentally got my wires crossed.

 

The pic below is a very typical Briggs configuration of two wires that support charging and headlights.

The "bulge" in one wire is a diode that supports the charging circuit and the "remaining" wire is the headlight wire.

 

The mag wire should be the third unidentified wire - disconnect this wire from the magneto, crank the engine and observe if a spark is present when the engine cranks over.

 

Since you saw smoke and the engine doesn't fire up, it would be a reasonable guess the magneto has burned up from touching a battery powered wire to the mag kill wire.

 

 

 

 

 

 

 

Edited March 19, 2016 by Save Old Iron

[russellmc301 600]

thanks,

when they put a new silinod on they messed with the wiring some so it doesn't have a male and female connector.

 

i have another 9 hp brigs and ill look at that.

 

Is that a snapper? looks a lot like one from the picture.

 

[Save Old Iron 1,563]

14 hours ago, russellmc301 said:

Is that a snapper? looks a lot like one from the picture.

 

 

No idea on that observation, I just pulled a random picture from a Google search to illustrate the bulge.

 

Once again, you don't need either of these connections functioning to check for spark.