Post the Sears 917.xxxxxx number.

You're saying that even at higher engine speed that you have to hold the key to the START position or else it will die?

It might actually be a seat switch/OPR issue, but one has to look at the proper schematic.

I have to hold the key at the start position for 10-30 seconds to get it to run. If I dont do this the engine will die as soon as I let go of the key. However, if I hold the key long enough, I can let go and the engine will run fine. It appears to be just an issue with getting it started, once it runs, it stays running and the idle/running speed is just fine.

Post the Sears technical model number (as suggested) because only that number will permit someone to view the proper wiring schematic online.
LT 1000 is nothing but a marketing model number and there are no specific documents to be had using it.
It s like saying Chevy Impala and not giving any year model or trim info or etc. And knowing the year of an LT 1000 is no help either.

Its model # 917.272082

What happens if you keep the brake/clutch pedal pushed in?

There is a bit of "non standard" circuitry in your schematic.
I have a hunch the problem may be something a bit obscure such as-
Key switch has a "sluggish" return from start to ON position and "possibly" the A1 terminal of the switch is having it's continuity disrupted?
Seat switch is making marginal contact.
OPR's "making marginal contact.".

I'd make sure the connecting plugs to the key switch, OPR's, seat switch are making good contact. Unplug & plug a couple times.

It would be helpful to determine if you are losing 12V to the carb solenoid, or if the OPR's are grounding the kill wire.
Temporarily removing the OPR's would eliminate the latter.
Jumping 12V direct to the carb solenoid would eliminate the former.

Keeping the brake/clutch is the only way it will get started. So that is what allows it to even turn over. I noticed that in the On position, if I turn the key a little, it turns the motor over, if I turn it all the way there is a Clack noise (or perhaps an electrical crack?) I know, I know this guy is describing noises his starter makes on the internet...

Please indulge me - what is an OPR? Operational presence relay?

How would i jump 12 to the solenoid?

Are you suggesting I bypass the OPR to see if they are grounding out?

Are there other possibilities for this issue? I noticed that in the fall, it started to get like this, then in early spring was fine then has really crapped the bed, starting wise.

Is there a good resource for diagrams, or better yet, a shop manual?

After reading your description of the key switch behavior, and Bill's account of the switch, I am suspicious that it might in fact be the cause of your troubles.
It is possible for material (actual pieces of metal) to shed off the moving contacts inside the key switch. The small pieces can then wreak havoc with normal functions of the switch, causing things to happen when they are not supposed to (or vice versa).
Make sure you use only the exact replacement part switch.
Many switches "look alike" respective of the number of terminals ad such, but can be configured differently in how those terminals function. So stay with OEM switch only.

"Keeping the brake/clutch is the only way it will get started. So that is what allows it to even turn over"
BUT- what happens IF you KEEP the pedal depressed?
Same thing or different?

OPR is Operator Presence Relay.
You have 3, but OPR 1 is the one in question.
It has to be powered by A1, through the seat switch to keep the kill wire from being grounded and killing spark.
This also powers the fuel solenoid in the ON position.

You could try one of these 2 things- (for test purposes)
Remove OPR 1 and see what happens.
OR
Jump across the seat switch terminals.

They do different things, but it may start us down the correct fork in the road-

Do you have the OM with the schematic in it?

Thanks for the suggestions.

The mower doesnt have anythign other than the brake clutch, so I have to keep it depressed till Im ready to drive it anyway. If I keep it depressed, the mower will start, eventually.

Ill look and see if I have the OM. I bought it used from a family member, so Ill have to check to see what I got.

So is there a reason that it may do this that isnt electrical? The only reason Im skeptical about electrical or switch issues is that it seems to need the electric start to keep running till its been going for a little bit. Maybe a coincidence? But once its been running, powered by the electric starter, it runs fine.

I mean, I can take it to the small engine repair guy, but I really like fixing stuff myself. Before the kids came along I rebuilt vintage scooters and british motorcycles. If I can breathe life into british iron, I can fix a damn mower...

That's a lot of reasons things happen.
We're trying to narrow them down, in spite of your reluctance.

Here's a link to a schematic. It's not exactly the same tractor, but the schematic is identical.
Page 33/64

http://www.managemyhome.com/mmh/lis_pdf/OWNM/L0804227.pdf

I tried both suggestions with no results. I disconnected the seat switch and jumped it, same starting issues. disconnected A1 with the seat switch jumped and not jumped and still the same.

Any more suggestions?

Disconnecting A1 will guarantee a no start. No power to the carb solenoid, which you could easily see on the schematic. No skill required on that.

Are you sure it was OPR1? Disconnecting all 3 won't hurt for test purposes to make sure.

Are you sure the choke is fully engaged when cranking?
Throttle cable might have slipped.

***" disconnected A1 with the seat switch jumped and not jumped and still the same."***
I fail to read where Bill suggested "disconnecting A1".

I meant OPR 1, I disconnected OPR 1. Ill try to disconnect all three and will check the throttle cable as well.

I don't believe you understand the significance (function/purpose) of the things going on here.
You CANNOT disconnect A1 at any time.
In fact, the circuit that is supposed to be powered by the key switch terminal A1.............might not be getting energized by the key switch at all right now (defective key switch).
This may get complicated (my explanation), so try to bear with me.
The key switch internal contacts that serve terminal A1 must be "hot" in the RUN position AND in the START position.
To do this, the rotary part of the switch contact has been given a very long stationary contact strip so A1 circuit does not lose its connection when the key is turned to the START position.
BUT! Circuit A1 is not powered ONLY by key switch terminal A1...................Circuit A 1 ALSO receives current directly from the voltage regulator output wire (feed path is through OP3 terminal 30).............but this "secondary" A1 power source DOES NOT come available UNTIL the engine RPM comes up enough to cause the alternator/regulator to make electric current.
So here is what I believe might be happening with your tractor now.
The key switch has a "dead zone" in the long stationary contact causing a loss of continuity to circuit A1 in the RUN position. But when the key is turned to START.....the rotary contact of A1 in the switch moves to a spot that DOES provide continuity........and so the fuel solenoid is energized and opens. And the engine starts. But, when you let go the key immediately, and it returns to the RUN position, A1 circuit becomes dead again. And because the charging system has not yet produced any "real" current yet............the fuel solenoid closes.....engine dies.
Holding the key in START position for long enough to allow the charging system to come online and substitute for a sound A1 circuit from the key switch may be "key" to ciphering how this unusual circumstance is manifesting itself in this case.
Testing this (this theory) could be as simple as providing a separate (temporary for testing only) source of power to the fuel solenoid that would eliminate the A1 portion of the electrical system by running a fused jumper wire to the fuel solenoid from a battery positive source (such as the battery + terminal on the starter solenoid).
I do not suggest you do any of this unless you actually know how to do real automotive electrical work! Having ever had your hands on Lucas Electric components does not count :^)
If the engine starts and does not die as soon as you let go the key with a proper test jumper wire connected to the fuel solenoid............you have cornered the problem.

Mownie - That makes TOTAL sense! Thank you for this suggestion/hypothesis. For the record, I mistakenly reported that I removed A1.

OK - I will take your advice not to jump electric to the solenoid. SO what other options does that leave me? I suppose I could remove the key switch and test continuity. Could I jump the wires coming into the switch?

If I cant/shouldnt jump the wires going into the switch and if there is no good way to test the continuity, then my only option, I guess, is to buy a new switch. Luckily they arent much $. Interestingly, your explanation lends credence to the electric crack sound I hear when I move the key around in the starter.

You have cautioned me to get OEM parts - Sears only offers a substitution

http://www.searspartsdirect.com/partsdirect/part-number/163968/0071/917?pathTaken=directMatch&filterPart=&pop=flush&prst=0amp;shdPart=163968

Is this sufficient?

Lucas electrics seems to only be surpassed by Sears electrics...

For Sears parts, Google-
AYP part#

You'll find parts for Craftsman, Husqvarna, Poulan etc., since they are/were made by the same company.

OK Mownie, I think you won the prize! I got home from work, pulled the ignition out, took the back off it and cleaned up the contacts inside the switch. It started right up! Ill play around with it some more later tonight when I have some more time but it seems to have fixed the problem, and for free to boot!

I sure hope that stays fixed.
I would not have suggested someone open a switch except for "autopsy " purposes because not everybody has the patience or skill to handle that. And some switches aren't intended to ever be opened and resealed either.
But anyhow, you know what the insides looked like and that is worth knowing, plus the results seem to be good.
Salooooooot!
When I say to get OEM parts I mean that you should buy parts that are a sound match for the components that come from the factory.
My cautionary advice is to keep someone from just picking out a switch because it "looks like my switch".
The switches all look very similar but the internal contacts and their corresponding terminals may not match in function, even though the harness plugs right up to it.
If Sears is offering a "substitute", that might simply mean they had problems with the original design and came up with an improved version, or it could mean they have changed suppliers for the switch or other reasons.
Point is that if Sears is selling you the switch based on accurate information from you (model number) the switch should work for you.

This post was edited by mownie on Wed, Jun 26, 13 at 1:08

Note: If you have ever worked on, or were exposed to Lucas electrical products--you would know why Mr. Lucas is called:"The Prince of Darkness! RJ

Note: If you have ever worked on, or were exposed to Lucas electrical products--you would know why Mr. Lucas is called:"The Prince of Darkness! RJ