Sabre 1438GS - stalls when trans or blade is engaged

eyoung

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Hey all,

I'm hoping someone may be able to help me out before I throw up my hands with this mower. I bought a 2000 Sabre/JD 1438GS 38" last week. I have two acres and have been using a walk behind so believe me when I say I want this thing going! Engine issues were a known when I bought it but everything else was supposed to be good as of early last season. Good news: I've got the engine running. Bad news: Nothing else is working.

Bear with me... I've always worked on my own cars/motorcycles but lawnmowers are a bit of a new world.

Engine:
It's a Briggs and Stratton 14.5 hp Intek OHV (287707). I'm going straight to the starter / frame to jump it to avoid anything in between. I adjusted the valves; the starter was bad so I replaced; sparkplug; etc. The solenoid is clicking rapidly when trying to start from the ignition so I'll likely replace, but for now the short story is that with fresh gas, a shot of starter fluid, and jumping the starter, the engine now fires up and runs like a top. Problem solved! I went to take a victory lap around the yard and here's where i'm now chasing my tail.

Transmission/Brake issue(?):
With the engine running and 'in gear' when I release the brake (whether slowly or quickly) it stalls out almost immediately. I can rescue it if I depress the brake right away. The reason 'in gear' is in quotes is because no matter what gear is selected and whether or not the brake is on still rolls freely, or spins freely if lifted as if it's in neutral. I can confirm that the linkage appears to be engaging the trans appropriately when shifted. Looking underneath while releasing the brake, the engine IS engaging the belt which seems to be causing the stall. No clue what these things could be symptoms of besides a shot trans, but that's the reason I'm asking you fine folks :wink: I would love to be wrong on this but to my knowledge there is no transmission release. I've looked everywhere.

Deck issue(?):
Attempting to either eliminate an issue or discover a new one, I tried to engage the deck while the engine was running and the brake was depressed. since they're on different spindles/pulleys I figured it should engage regardless of the trans. Same issue... It stalls, but If I disengage right away I can rescue the engine from stalling.

I was trying all of this testing while seated on the mower with all four tires on the ground. Currently, I have it jacked up with one of the rear wheels off for access. I also have a jumper attached to the seat safety switch to eliminate a variable while I test this thing out.


If you all have any thoughts I'm all ears! I can take pictures of anything, if needed, as well.

Thanks!

Ed
 
Last edited:

bertsmobile1

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First thoughts were a jambed belt but as the engine stalls out under load I am inclined to go down the duff governor path or missing main jet.
You will need a 3rd & 4th hand for this.
Start mower, watch the governor shaft as some one else engages the blades, it should move to open the throttle to compensate for the load.
If it did not move, repeat while moving the governor by hand to open the throttle some more.
Watch where your toes are when you do this, deck fully down.
Governor might be out of adjustment or broken.

Watch the exhaust as the engine stalls out under load.
If you get some black smoke as the engine stalls then the main jet is missing or enlarged
Go around to the other side and with noting other than the engine running slowly mover the governor to open up the throttle.
The engine should accelerate smoothly. Dont go overboard as excessive over reving can do a lot of damage.
If the engine dies out like it is running out of gas, then that is most likely what is happening .

Pop an in line spark tester on the plug.
If the flashes go out when the brake is let off and when the PTO is engaged then the seat switch is faulty.
let us know what happens
 

eyoung

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Thanks a ton for the advice - about to head out for the day with the missus but I'll be able to try those out later on today / tomorrow morning. I'll update after trying!
 

eyoung

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Here's what I did, and here's what worked/didn't.

With the inline sparkplug tester in place...

Deck:
Apparently I didn't try to engage the deck while using the seat switch directly as originally stated, only jumpered. This was a big miss on my part, which I thought I had tried. I lowered the mower and had the missus sit on tractor with the switch jumpered and when she tried to engage the deck, NO LIGHT. I then tried it with the seat switch plugged in and tried again - the deck engaged perfectly; no engine bog at all! So now we have a working engine and working deck.

Trans:
As with the deck, the first attempt yielded no light since the jumper wasn't working. With the seat switch back in place the light remains on and engine doesn't stall. Taking a look underneath, when the brake pedal is released the belt tensions and engages the trans, but it starts to smell quickly of hot belt. It looks like the trans pulley isn't moving, but didn't stick my hand in there to fully confirm :smile:

So the remaining issues are:
When shifting (no matter the gear) the axle spins freely. When the brake is depressed (which is attached to the trans) the wheels/axle spins freely. Any thoughts besides a new trans? Doing some googling it doesn't appear that it has any sort of release.
 

bertsmobile1

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There is a bypass valve on the tranny so you can push the mower.
Occasionally they get activated by stuff you run over, vibrations , sticks & stones etc.
Sounds like yours might be open.
If you pushed it onto the trailer to get it home, the vendor probably opened it so you could push it.
They get hidden all over the place so get under the mower and look for a small lever with a thin control rod on it , not heading foreward towards the pedals.
Follow it to where it comes out.
Some JD's hid them behind one of the wheels.

or

The pulley on the tranny sits on a fine spline which is prone to stripping out.
The belt should get warm, but not too hot to touch and definately not smell burning.
That usually happens when a pulley is running against a belt that is not moving.
Occasionally you get the burn smell form a bent running over a frozen pulley but generally you can hear it objecting as a squeal.
 
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