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exp2ex

Ignition Question

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Ok. got the beast to run just fine, BUT ......

It will only start with the key if I have a line going from the hot side of the start solinoid to the - side of the coil. I then have to make sire the points are not closed when it is not running.

Any ideas as to what would let it start like this and not when the wire is not there ?

Thanks,.

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:thumbs:

sounds like the start solinoid is shot

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That would be my guess also.

Bob

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Sounds like the coil isn't getting power when the key is in the on position. This could be the key, or wiring from the key switch to the coil.

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Ok.

Replaced the start solenoid.

sat on the tractor. turned the key and ............................

Presto ! engine turned over without the jumper cable from the solenoid to the coil.

Engine did not start because I was so stinkin happy that it turned over.

Went to turn key again and .............................

Nothing.

Reattached the jumper cable and it turns over.

YOUR THOUGHTS !!!!!!!!

Thanks.

Degan

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Does this tractor have the ammeter in the center of the vertical console? If so, disconnect the 2 wires going to it which are only spade terminals and check the meter for continuity. If this doesn't read 000 on the meter than this is most likely the culprit.

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Does this tractor have the amp meter in the center of the vertical console? If so, disconnect the 2 wires going to it which are only spade terminals and check the meter for continuity. If this doesn't read 000 on the meter than this is most likely the culprit.

Ok., Checked the wires. I have no reading on the meter itself. there is 000 for cont. between the two. (meter does not beep) While running the 20v setting on the meter reads 1.25 at 1/3 throttle.

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Sorry I guess you already did that. Did you take the battery in and have it tested? Autozone is generally a god place to put it thru it's paces.

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Sorry I guess you already did that. Did you take the battery in and have it tested? Autozone is generally a god place to put it thru it's paces.

Battery is good.

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Next, I would check the ignition switch in different positions for continuity next. I would also check the starter and brush conditions. Does the bendix move freely? I would also acquire the wiring diagram and check continuity at every wire. Check the harness at the back of the ignition switch.

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Next, I would check the ignition switch in different positions for continuity next. I would also check the starter and brush conditions. Does the bendix move freely? I would also acquire the wiring diagram and check continuity at every wire. Check the harness at the back of the ignition switch.

Ok. Will do.

I am not that strong in the electrical knowledge of engines.

This is my classroom so to speak.

So here are some more questions.

THe start solenoid has a hot line on it all the time ? Yes ? Direct from battery.

The other large lug is for the line to the starter ? yes ?

The small lug is for a line that comes from the switch which when turned to start will trigger the solenoid to feed power to the starter ? ?

Why would a line from the + side of the start solenoid to the - side of the coil let me start it just fine with the key ? I am confused.

What does the line that goes to the - coil side do and where does it come from. ?

The + side of the coil has the red line that goes to the points and the small condenser ?

If I check continuity of my battery + and - should there be any ?

Should there be continuity between the + battery terminal and the frame of the tractor ?

How can I bypass all my safety switches (seat, trans lever, brake, & lift lever) ? Maybe there is one I don't know about .

Bendix moves freely. and i did check the switch for continuity through all positions.

I need a schematic. I will get one tonight.

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OK..... this isn't right.

First of all, the power from the ignition switch "I" terminal needs to go to the POSITIVE (+) post on the ignition coil.

The condensor lead and the wire to the points both attach to the NEGATIVE ( - ) post of the coil.

You are currently able to get it to turn over because you are backfeeding power through the wire TO the ignition coil back to the switch by hooking up your jumper wire.

You need to establish the power feed from the battery side (small gauge wire with a large ring terminal on the big post with the battery cable) of the starter solenoid to the "B" terminal on the ignition switch. This wire is actually "split" at the ammeter. (wire from solenoid to ammeter - wire from ammeter to "B" terminal on switch.)

Once you have battery power to the ignition switch, make sure the switch is good.

You should get power at the "S" terminal when the key is turned to the start position.

You should have power at the "R" and "A" terminals when the key is in the on position.

You should have power at the "I" terminal when the key in is both on and start positions.

If one or more of the above connections do not work, you need a new switch.

The wire from the "I" terminal on the switch eventually (passes through safety switches) supplies the power to the ignition coil.

The wire from the "S" terminal on the switch eventually (more safety switches) supplies power to the small post on the solenoid.

Running wires directly to those two places will bypass all safety switches and should get you back in business. Bypasssing the safety switches is not advised, but if you choose to do so, do it at your own risk. (disclaimer on my behalf)

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Ok. Great. Thanks for all the info.

I am plowing over the manuals and schematics that I have.

I changed the coil wires

I have tested the switch harness. While I am sitting on the tractor with all safety switches in the correct position to have it run.

I am not getting any power to any wire in the switch harness.

I am pretty sure there needs to be power to the switch.

Thanks all.

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You need to establish the power feed from the battery side (small gauge wire with a large ring terminal on the big post with the battery cable) of the starter solenoid to the "B" terminal on the ignition switch. This wire is actually "split" at the ammeter. (wire from solenoid to ammeter - wire from ammeter to "B" terminal on switch.)

Did you check for power at the ammeter connections? One of those two wires should have power. If the ammeter is "good" the power should travel through it and feed the ignition switch.

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You need to establish the power feed from the battery side (small gauge wire with a large ring terminal on the big post with the battery cable) of the starter solenoid to the "B" terminal on the ignition switch. This wire is actually "split" at the ammeter. (wire from solenoid to ammeter - wire from ammeter to "B" terminal on switch.)

Did you check for power at the ammeter connections? One of those two wires should have power. If the ammeter is "good" the power should travel through it and feed the ignition switch.

I have power to the ammeter but did not have power at the switch harness.

Problem solved.

bad connection outbound to the switch.

TT , thanks.

I have really enjoyed trouble shooting this issue and thanks to all who have helped.

I went from wanting to well this c121 2-3 weeks ago to buying another and getting this one going with jumping the switches.

Thanks again.

Degan

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Excellent! :banghead: Glad I could help.

You did switch the wires around on the ignition coil, didn't you? :thumbs: :WRS:

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Excellent! :banghead: Glad I could help.

You did switch the wires around on the ignition coil, didn't you? :thumbs::WRS:

Yes. My son just drove it all around in the rain.

Started up quickly and seems to be just fine. Very large smile here.

I have owned this c121 for 7 years. Have only put about 20 hours on it before things went south. Then put her away 4 years ago and decided to sell it then decided to get it going. I am thankful for all the help to get her going again and for a better understanding of electrical systems. The lights work now as well !

Thanks again.

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It won't be long now until you buy another to keep the C-121 company. :thumbs:

Uhhhhhhh.

Got another one 3 days ago.

66 656 from Bethlehem PA. Found it online and made the fellow a offer. Really bought it as a spare 12hp for the 121 just in case I ever need one. Came with cutting deck in very good condition, and a snow plow that looked like never used.

Even has wheel horse rubber on it. $400

Has a 12 Kohler in it but also came with the orig 6hp. Runs great.

I am looking for a new engine cover for the 121. The cover that the coil attaches to. After that the 121 is good to go.

Thanks.

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