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Stx 38 (or 138?) Won't Start

16K views 14 replies 7 participants last post by  New.Canadian.DB.Owner  
#1 ·
I have a chance to buy an STX38 that won"t start. Their mechanic says it won't start because the tranny won't go into neutral so the safety switch won't reset. Is this a "run away as fast as you can" or quick fix? Is there a quick way to tell?

It should have a 12.5 or 13 hp Kohler. The mechanic also says the compression is low (60psi) which tells me he ran a compression test, not a bleed down test, which tells me he may or may not know what he is talking about. Any thoughts on that?

The owner claims it is an STX138. I can't find the 138 on the web anywhere. Is there an stx138 and an stx38?
 
#2 ·
if he is an automechanic he may not be aware of the compression release on these small engines.make sure the tractor is in neutral and blade disengaged then, find the kill wire to the engine and disconnect it and the motor should start if the safety is the only problem.be aware that you just disabled the way you shut off the engine . i would be most concerned why the tranny wont go into neutral.
 
#3 ·
I would definitely proceed with caution on that one. Like rexknightly said, my biggest concern too would be why you can't put the transmission in neutral.
 
#4 ·
It's an STX38. We see a fair number of them up here. It's a Peerless 920 transmission I think and I would be very cautious on this one. Potentially the engine is worn out and the transmission broken. It could be a linkage problem if you are lucky. Otherwise you have a more serious internal problem.
 
#7 ·
So here are the pictures. It is a yellow deck STX38. JDBrian was right, it should have the Peerless 920. It has a few problems beyond not starting & a dead transmission, but for $75 how could I say no?

As I expected, the transmission lever "free floats" (there is zero resistance when it is moved through the gears). I expect this means the shift rod & fork has snapped. I'll know more once I split it open.

I ran 12v to the starter terminal, and the engine does turn over but not fire. That could be because it is missing the seat switch. I hope that is what was connected to the wires marked "710". They are located in the battery compartment. Anyone know for sure?

I looked at the starter interlock circuits, but don't find a transmission neutral switch. Anyone with a better wiring diagram, or more knowledge, is encouraged to share ;}.

Here is a stupid question: the toggle switch on the right console just forward of the key, is that the electric PTO switch? If not, where is the electric PTO switch & what is this switch for? Never thought to ask the seller.
 

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#9 ·
So, I pulled and split the transmission today. Pretty painless. A couple of 1/2" bolts & it is out. Seventeen 3/8" bolts and it is split. Finding the 17th bolt was the hardest part. It was hiding under the input pulley.

Turns out the tractor is a 1988 & it has a Peerless 915 012B. I hear that it isn't uncommon for different parts to appear in the first model year. Anyway, the problem is the same: snapped Sift Rod and Fork.
 

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#10 · (Edited by Moderator)
I ordered a replacement shift fork & rod (AM117597) from John Deere on Tuesday, and it arrived on Friday. It has been beefed up at the point of breakage. I had to drill out the cap screw (M78560) as the previous mechanic had rounded the head. It is just a 1/4" - 28 x 3/4" bolt.

More later.
 

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#11 ·
I reinstalled the transaxle today. The wires marked "710" are for the neutral switch. Go figure. It turned over but just briefly. Sounded like a dead battery, but the battery is good. I think I'm going to do the relay assisted start mod I found on another forum. More on that later. Here is the diagram.
 

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#13 · (Edited by Moderator)
In the pic, it says to "disconnect the battery before starting". Don't you need the battery to start it?
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Guess that means to disconnect before starting the installation. Glad it worked! Need to file that away (but I would probably forget where I put it!).
 
#14 ·
"Here is a stupid question: the toggle switch on the right console just forward of the key, is that the electric PTO switch? If not, where is the electric PTO switch & what is this switch for? Never thought to ask the seller"

Not a stupid question the electric PTO is controlled by a toggle switch on these tractors I had an stx38 it was a great little tractor my switch was located on the fender rt side near the shifter.