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McGaw 04-27-2008 05:25 PM

How to hot wire?
Hi there,
I have a really old, like 50's model, case lawn tractor. 10 hp 46"? cut. Just wondering if anyone could tell me very easily how to hot wire it, or if they could provide a diagram? That would be very helpfull. Thank you very much.

47_47 04-28-2008 08:49 AM

Why do you need to hot wire? Have you lost the key?
What does the tractor do?
No crank?
Crank/ no start/ no spark?
Do you crank the engine with the key or does it have a seperate switch?
6 or 12 volts? Positive or negative ground?
Starter relay or solenoid?
Do you plan on mowing with this tractor or just need to move it?

McGaw 04-28-2008 12:57 PM

My neighbor was interested when I told him how old it was and told me I should hotwire it, make sure it works.
I put the key in, turn it, press the starter button, the starter will spin. It won't "roar to life" though. It's moving fast enough. It is a hydrostatic and we had to re-align the pump. I'm just not sure what to do next. I'm going to try a new spark plug. It does have a seperate switch. It's 12 volts. I beleive it is negative ground. I plan on mowing with it, as well as pulling with it. I've got a couple of pics and I will go out when it stops raining to take some more.

McGaw 04-28-2008 01:31 PM

1 Attachment(s)
pic 1

47_47 04-28-2008 02:32 PM

Hydrostatic should be for just the drive, mower or PTO and should not have anything to do with the engine not starting.

Four primary reasons for this not to start.
No/ weak spark
No/ contaminated fuel
No air
Compression/ timing

All areas must be in reasonable working order for the tractor to start. I would follow a systematic approach and check them one by one. Below is what I would do.

Inspect/ replace the plug. Check for spark by removing the plug wire and attach it to a spark tester. You can use another spark plug as a tester, connect the wire to another spark plug and ground the plug to the engine. Have a helper try to start the engine and you notate if you have a blue spark. Do not use this homemade tester near fuel or vapors. If you have spark, hot wiring will not help, the ignition system to the plug is fine.
Hot wiring in your case would be to run a wire from the (positive battery, if negative ground) to the + primary terminal of the coil, turn the key to run and push the button to crank the engine. You are appyling full battery voltage to ignition system.

Remove the air cleaner and spray a small amount of carb cleaner into the carb. Do not use starting fluid, it strips all internal lubrication from the cylinders. Try to start the engine. If it sputters or seems like it wants to fire, best results are to hold the throttle almost wide open and repeat. Do not allow the engine to over rev, your oil will need a little time to circulate.

Check the engine compression with a gauge. I do not know what it should read, but older engines should be around 60-80 psi. If the compression is low, you may have a stuck ring. Put a 1-2 table spoons clean engine oil into the plug hole and allow it to set over night.

If you narrow it down to an area, I'll try to help you further.

Sweet machine, take a few picture under the hood.

McGaw 05-02-2008 04:35 PM

6 Attachment(s)
I think I figured it out. Put a new spark plug. Still nothing. My friend told me it's probably because I have to run a wire to or from the points or something. He's got a case so he said he'll take a look under teh hood of his and see where the wire should go. We'll see if that works.
I did manage to take some pics.
Model is 155
No. is 9616075
Manufactured in U.S.A.
J.I. CASE Company

McGaw 05-02-2008 04:37 PM

1 Attachment(s)
One more.

47_47 05-05-2008 07:46 AM

Check for battery voltage with the key on at the + terminal of the coil with a test light. If you have power here, the primary side of your ignition is ok up to the coil and hot wiring will not help. That is the one you would need to apply battery voltage to hot wire. I would remove the spark plug, ground the metal shell, not the ceramic insulator to the head and have a helper try to start the engine. You could either hold it to the head with insulated pliers and do not touch any other part of the tractor or use a jumper wire. If you have spark, then the reason for a no start is probably elsewhere.
Are you getting fuel to the carb? Remove the 1/4" line and check. Is the fuel fresh?
Let me know.

McGaw 05-06-2008 09:14 PM

With some work, we got it figured out. Found out the wires were just switched around. haha. Thanks for all your help. Runs like a champ now. Well except we need some speed clips(?) for the throttle and choke.
Think I might just tack them on with a welder.
Anyone know where I can get them though?

47_47 05-07-2008 06:45 AM

Glad to hear you got it running. Do not weld the cables in place. You will also weld the inner cable to the outer sheath. I'd phone auto parts stores, or small engine / lawn mower repair shops. A lot of people generally buy new mowers in the spring and you may find something at the curb that would work.

McGaw 05-07-2008 02:03 PM

Ok. Thanks.
I've called around to every shop I could think of or find in the phone book. Noone had any or they said I would have to buy the whole motor. A few people said they've never heard or seen of them.
It backfires. Any way of stopping that? Or tuning it somehow so it doesn't consume so much gas?

47_47 05-07-2008 03:20 PM

Not really a small engine tech, but is the choke plate open and not fully closed as in your pics? Trace the wire from - side of the coil and let me know where it goes. It should go to the points or similar primary triger mechanism. Pics of this area will be helpful.

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