Wiring is the easiest and cheapest to start with. Take the cable off of the starter, clean and inspect it.

Forgot to mention that I have cleaned (and inspected) the connections to the selenoid and starter motor. This has not helped.

thank you --- dave

If you have a voltmeter, you can do voltage drop tests across EACH individual connection.
HAVE you checked the actual ground from starter motor to engine block to chassis ground to battery ground?
People tend to check the "RED" connections, but ignore the "BLACK" ones. They are equally important!

Excellent troubleshooting so far.

Bill is correct. Placing a volt meter accross various point will tell you quickly if there really is a bad connection somewhere.

My guess is that it is (was?) the starter. These have brushes and a commutator, so you could have worn brushes and or corrosion on the commutator (does it live outside?).

Don't forget you could have a ground problem.

I would try the following. Connect your jumper cables from the truck directly to the engine (negative) and the terminal on the starter. If this does not work, then tak eapart the starter.

If it does work, try moving the negative jumper cable to the battery and see if it still works. If not look for bad cables or conections on the ground side of the circuit.

If it works with the negative jumper to the battery then try moving the positive cable to each of the following points:

1) Output side of the solenoid

2) Input side of the solenoid (now you need to start using the key again)

Good luck

Bill and Wheelhorese are right on the money with that advice. The ground side of the circuit is just as important as the positive. I'm betting it's one or the other(starter or grd curciut) on your machine. Most computor curciuts in vehicles use the grd side to turn on and off various soleniods/etc. I've been useing my garden tractors for years moving trailers around, made a hitch for the rear lift with a 2" ball on it, don't even get off the seat to hook/unkook the trailer.

8u have a pic of that lift idear??

How about taking the starter motor off and testing it off the engine, it should try to torque out of your hand. Second how about disassembling the starter motor and giving it a good cleaning and check the brushes.

Cleaning and inspecting is very cheap, it just costs if you find something wrong.

I had a Roper rear engine rider with a 8hp briggs on it. It sounds very similar to yours. Is the battery nearly impossible to get to, requiring removal of much sheet metal for access? Mine had the engine and transmission inside a metal box and the seat was on top of that. The key and throttle was on the front side of that box, below the seat. I remodeled it into a go-kart, believe it or not.

Anyway, that engine cranked over very easily. If the thing is not cranking very fast, the other suggestions are probably correct. Either you have a voltage drop (bad connection) somewhere, or you have a bad starter. By the way, you aren't missing much without the deck. It didn't mow very good anyway.

Q: Is the battery nearly impossible to get to, requiring removal of much sheet metal for access?

A: YES - For the most part - it does sound a lot like your description. I need to remove a metal side panel from the mower in order to get to the battery - and as i mentioned - this battery starts my 20HP Scotts/J.Deere I have a high level of confidence in the installed battery.

CURRENT STATUS:
-------------------------
After snow blowing my driveway this morning I decided to have a closer look at the Old Sears clunker (i wanted to put it in 5th gear and pretend it was a quad and have some fun in the snow with it ... :)

Heres what I found - I removed the starter motor and upon disassembly i immediately noticed a lot of debris in the circular housing... it was a magnetic debris and upon removal of the rotating component in the housing I see that 3 magnets are stuck to the rotor - and a 4th seems to be epoxied to the housing....

Hmmmm... maybe this is my weak starter problem ....

For what its worth - The brushes seem to be in fair condition...

SITUATION:
-------------------------
The old sears doesn't have a mower deck or anything ... so i cant really justify spending a bunch of money for something that doesn't have a whole lot of utility to me... If im going to spend "big money" on something - its going to be a bagger for my Scotts/JD mower which is sorely needed...

QUESTIONS:
--------------------------------------------------
Since im on a low budget Im wondering if I can epoxy those magnets back onto the housing ???

what type of epoxy should I use ?

how much is a starter for an 8hp briggs?

Do people rebuild these units ?

what about a pull starter for this engine ? I still have a strong back ...

Theoretically you COULD epoxy the magnets back in place with JB Weld or an eqivalent. The catch here is: When the magnets are placed at the time of manufacture....they are oriented in a specific direction as determined by the polarity of each magnet. Unless you can determine which way that would be, you have a 50% chance of placing each of the loose magnets back with incorrect polarity orientation. This, of course, would produce a "nullifying effect" of the rotational forces that cause an electric motor to spin. When magnets are found loose or broken in this type of starter, it usually means someone has beaten the starter (into submission??) with a hammer or other tool because they hope it just needs a nudge to exorcize the "no-start demons". A competent "automotive electrical component rebuilder" might be able to determine (and repair if you like) which way the magnets need to be positioned.

JB Weld hmmm - Never heard of it ... but after looking around on the web it appears to be the stuff ... ill give it a shot ...

I was initially concerned that the heat would be an issue with whatever epoxy I selected but it appears that this stuff will work well with my situation...

Regarding the placement of the magnets:
---------------------------------------------------
Interesting that you mention this My brother mentioned the same thing When I slid the armature out of the housing the magnets where stuck to the armature and I have not removed them ... Therefore I have not altered their orientation.

I will mark them carefully before removal, cleanup and placement back into the circular housing. My brother was saying that since the starter was working sluggishly until the moment I removed it that I have a pretty good chance of getting it working as long as I don't screw up the magnet placement.

So Ill give it a shot and see what comes of it ...

NOTES:
-----------------------------
Interestingly one of the magnets is badly chipped, but in such a way that I feel the magnet is not significantly compromised. Imagine a cylinder (of this black magnetic material) which is then cut into 90 degree quarters lengthwise down the the cylinder... Well one of then is chipped on the inner surface for what might be the full length of the magnet (very strange)...

if anyone would like to see photos of what Im dealing with please let me know and I can send you some pic's. (I don't have a web server I can post them to).

QUESTIONS:
---------------------------
The armature and other internal components are black with magnetic dust/grime and such... I have used gas to clean off the brushes and end caps .... But Im not sure I should be using gas to clean the armature and windings What should I use to clean up the armature and related components???

tomorrow im heading out for the JB Weld wish me luck!

thank you - Ill keep you posted on my progress ...

The armature and other internal components are black with magnetic dust/grime and such... I have used gas to clean off the brushes and end caps .... But Im not sure I should be using gas to clean the armature and windings What should I use to clean up the armature and related components???

I used to use TV tuner cleaner to was small DC motors. You can find this in an electronics supply shop (not Radio Shack, though).

If you can't find a good electrical/electronics spray cleaner, use paint thinner or mineral spirits (but never use lacquer thinner or carburetor cleaner, they will attack the shellac or varnish type insulation that the coils are coated with...instant short circuits)
You need not look too hard for JB Weld..It is found in home improvement stores, department stores, auto parts stores, hardware stores, heck, it's just about everywhere. I can't believe you've never used it, much less ever heard of it. Go figure! But good luck anyhow. Since you did not change the polarity orientation of the magnets, I think you'll have some luck.

I found myself some JB Weld (cant believe Ive never heard of this stuff before)...

and Im gluing the magnets back into the housing and Ive foresee a problem with assembly perhaps some of you have been down this road

As I have cleaned off this DIRTY FILTHY unit the 4 brushes are now freely moving again (1 or 2 were stuck in their housings) Naturally the 4 brushes will not stay in their proper locations (within their housings) to be expected as they have springs behind them

The question:
------
The JB Weld (a.k.a. magical go-go juice) will be cured by mid-day tomorrow and I will be assembling the unit for test (I cant wait!) But I can see that re-assembling the end cap with the 4 brushes hanging out of their 4 little housings is going to be a tricky task Trying to get the 4 brush end cap over the armature is not going to be a no-brainer

Do any of you guys have any tips or tricks for holding those little brushes in place while Im trying to assemble the starter unit?

Thanks again all !

Most of these brush holders are provided with a pair of holes near the commutator end of the holder to allow a "brush retainer tool" to be inserted (read that as a round wooden toothpick or similar non-metallic item). The real trick is that most time the brush holders can be separated from the actual end cap so you can get the brushes onto the commutator first, slip out your brush retainers, and lastly fit the end cap over the brush holders. I hope this is how your starter is configured (probably close).

Ok that solved my assembly problem... Mine had no holes - But after a visit to see Mr Drill and his cousin (1/16 drill bit) the unit has 4 conveniently located holes :)

I used 4 wires from an old ribbon cable which came from a computer... separated 4 wires from the cable, cut them to about 4 inches long ... (you get the picture)...

I inserted the end cap into the housing and pulled the 4 wires and its conveniently assembled...

Results:
-------------------
After i assembled the unit all i got was a clicking from the selenoid... (and I saw some smoke come from the starter motor again - not good ) so im going to try and use a jumper cable to simply touch the negative to the starter body and the positive to the positive connector on the starter...

I guess if I see the starter motor actually work - then I should now start looking more closely at my selenoid ?

Thanks - Dave

Update:
-------------------

After fooling around with the Starter a bit i see that when i turn the ignition switch - I can feel the starter motor is trying to do something... it would seem that my efforts are for nothing...

Oh well - off to see how much a start motor is ...

Any other ideas - anyone ?

anyway - Thanks for all your help...

If those brushes were well worn down, one or more of them might be so short that it/they tilted in the brush holder and "spragued up", effectively locking the armature (rotor) and/or shorting between more bars of the commutator than the law can allow. Did you clean off the original layer of "epoxy" before putting down the new layer? If you left the old layer in place (on the field case or on the magnets) you may have decreased the gap beteen the magnets and the armature laminations enough to cause physican interference and lock up. The OEM air gap between the surface of the magnet and the surface of the steel laminations of the armature is about the thickness of 2 sheets of standard printer paper, that's why it only takes a little wear in the starter end bushings to make a starter "drag". Can you turn the starter motor by turning the drive gear (Bendix)? IT SHOULD FREE WHEEL in one direction (only one), but you should be able to turn the armature in the opposite direction (with some effort, probably need to grip the gear with pliers). If the armature WILL NOT turn, either the field magnets are touching the armature laminations, or the brushes have tilted in their holder and are locking against the commutator bars. The solenoid itself can't cause the smoke you see coming from the starter case. The solenoid is just a combination "pull-in plunger to move the drive assembly toward the flywheel and a heavy duty set of contacts to carry the electrical load of the motor. Oh well, it was worth a try and you learned a few things.

Tf your lucky this one might be the replacement starter,
I have bought several items from this guy, good prices and fast shipments.
http://cgi.ebay.com/Briggs-Electric-Starter-SINGLE-CYLINDER-394805-497595_W0QQitemZ180166315345QQihZ008QQcategoryZ50371QQtcZphotoQQcmdZViewItem
Although a lot of the older sears tractor engines horiz shaft were Tecumseh engines - and they only had sears ID on them -

Since the value of the tractor dictates your budget (same as for me) don't buy a new starter, find a used one on ebay.

It might take a while, save the search and use the auto notify option. You will find one.

Also, probably worth pulling it apart one more time to check the things mentioned above.

Best of luck.

You guys have been VERY helpful - wish i could buy you all a beer...

Turns out the engine is a Tecumseh and NOT a Briggs & Stratton ... No where on the engine did it say Tecumseh - I finally found a sticker on the side of the engine with some numbers which turned out to be sears parts numbers and then finally I traced a part number to 36680 (a tecumseh Starter motor part number)

Anyhow - i found a couple of aftermarket starters for the about $49-59 dollars a real Tec. Starter (#36680) is about $125 bucks (definitely not going to happen).

I question the value of this tractor no cutting deck, rough shape, etc. --- I would not pay $50 dollars for the tractor - So Im not sure I would spend the $50-60 to actually repair it...

As suggested - I will continue to search for a bargain starter - I know if I wait long enough Ill get it for a good price...

BUT to confuse things further
- - - - - - - - - - - - - - - - - - - - - - - -
Today I ran into someone who put out an older Snapper lawn mower with a 8hp Briggs and a 30ish inch cutting deck onto their front lawn (for free!) Its rough - but its free... (wow - that 8HP B+S engine is a lot bigger than the 8hp tecemseh engine)

Its a pull start unit (no electric starting), owner tells me it will fire up with starting fluid but wont run, it did run last spring...

So Im thinking Ill "grab her snapper" - toss the sears tractor (but keep the tecumseh motor just in case). And work the Briggs motor/carb into something usable....

QUESTIONS:
-- - - - - -- - - - - - -
1. Do any of you happen to know if theres enough meat on the back of that funky looking Snapper tractor to mount my crumy little ball hitch to drag around my trailers? The Snapper Im talking about looks roughly like this one http://www.snapper.com/rear_engine_riders.html except older i did not think to look for that when i was looking the snapper over...

2. Do any of you know if the engine mounting bolt patterns for a 8HP Tecumseh and a 8HP B&S engine are the same??? Granted the snapper has the mowing deck (but I got a scotts 2046 for mowing). The sears is a good slow mule for my intentions of moving trailers, moving stone and logs around the property Plus im gonna have to take the pully into consideration (that sounds messy)... im guessing crank diameters dont match...

3. Do you think the Snapper has a torque-y transmission transaxle (whatever it has under there) to do roughly what Im doing with my Sears? The Snapper Im talking about looks roughly like this one http://www.snapper.com/rear_engine_riders.html

Im thinking the Snapper might be a good choice Your thoughts please
Mucho Thanks - Dave

If you're talking about an old rear engine Snapper rider they were very tuff mowers but really not meant to be used as a tractor. Snapper used a flat crank plate with moveable input rubber wheel, wasn't really any transmission to it. You would have to make sure the cranks are the same lenght and diameter so the Snapper plate would fit. Mounting holes are probably a little different between the two motors but thats easily solved. My advice would be to get the old Snapper as a project to tinker on when ever you feel like it, watch e-bay for a good used starter for your present tractor. Little tinkering,little paint, maybe sell the Snapper for enough profit to pay for the starter you need. Just a thought.

Get off your pocketbook...buy a new starter.

"so i cant really justify spending" I would spend alittle money to get out of scooping snow. Snow blowing is worth every dime to me! But, you must be younger and haven't worn out your back YET! Too cheap to buy a starter, then get a pull rope housing for it. But, it will proabably cost as much as starter. Goto lawn mower & small engines - nations starter alternator www.nationsautoelectric.com/Smallengine.html and price one

Njdpo,
Where are you located, I may have a starter that will fit your engine. I used it on a 7hp Sears horizontal engine.

I used to have a 10hp RER craftsman. Ate starters for breakfast. Put around 500 hrs on it and went through 5 starters. at around 75 hrs, it would quit. I'd have to JB-weld the magnets back on, then it'd give me 25 hrs and it'd die for good. I'd then replace it for $80. Repeat five times and that was the way things went. An amazingly reliable mower except for that.

PS Mine, unlike the snapper, used a gearcase driven from the engine by a belt and to the differential by a 1/2" chain. Very sturdy. I towed my boat across the driveway with it every winter and a garden cart almost every day in the summer.