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Sabre ubrubtly shut down, and will not restart

3147 Views 8 Replies 5 Participants Last post by  draaino
Ok, I have a Sabre lawn tractor with the 18hp intek vtwin. I was mowing the lawn one day and all of a sudden it quit running. I thought I ran out of gas, but no.
Now, I have been starting my lawn mower by bi-passing the starter switch. My positive battery cable at the battery is corroded and wont get a good connection. I haven't got around to replacing it. So I would just jump the starter with a jumper cable from the positive terminal to the starter.
now that we got that out of the way. The tractor was not out of gas. I checked the oil, and it was a bit low. I put oil in it. Wentto jump start it, it cranked over but would not fire, but immediately smoke came pouring from the front of the engine. Smelt like electrical. Sure enough, a ground wire fried on the front of the engine. I have no clue what it is. Fuel shut off switch? It's on the bottom of the carb. I sprayed carb cleaner in the air cleaner to see if it would fire up. It fired up immediately with more electrical smoke, I heard a bad knock during the 2 seconds it was running. I also noticed some oil leaking from the left side of the engine.I have had nothing but problems with this sabre, but never the briggs engine. It looks terminal, but who knows, maybe it's an easy fix? help is appreciated! Thanks
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Does not sound good but there are many experts on here and I'm sure they can give you some ideas of what to look at. You may want to have someone local take a look at it so you can evaluate what it would take to get it back into running shape.
Welcome to the forum.

Put away the bandaids now!

First, you have electrical problems as you well know. You've been patching along and now they are worse.

Stop right now, get a schematic of the electrical system, and check, clean and repair every connection on this tractor. EVERY CONNECTION. No loose connectors, no corroded connectors, no bare or abraded wires, etc.

Once the wiring is straight, verify you have not overfilled the oil.

Clean the engine up and look for the exact source of any leak if there is indeed a leak.

Check the condition of your spark plugs against any of the many charts available on the internet. Are you running lean, rich, hot?

Check your valve adjustment if applicable - you'll need a service manual to be sure of specs and tolerances.

I don't mean to be terse, but there is no easy fix to this problem. It's going to require a lot of work. Trying to patch along is begging for more and more serious problems.
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Your description of the condition of your tractor and the "Saturday night mechanics work" says that proper repairs aren't being done. You can't neglect equipment and then expect it to work perfectly. You may have already gone beyond what can reasonably be repaired and will need to put some serious cash into this to get it back up and running properly. D-Dogg has advised you correctly on getting the manuals and diagrams and understanding your tractor (we all have to learn this!). The service manual for a tractor is a worthwhile "investment" not an expense! Check all the wires before you cause a fire and destroy the tractor.
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Hi draaino, and welcome to the forum.

I agree with D-Dogg about cleaning up the electrical system, especially the corroded (+) battery lead.

Having said that, the symptoms you describe are exactly what one would expect if the lead to the cutoff solenoid on the bottom of the carb bowl were to short to ground. The engine would stop abruptly (since the solenoid wouldn't have enough juice to keep it energized) and the smoke would be coming from the melting insulation on the wire. Funny it didn't blow the main fuse, but some of those wiring setups only fuse the battery circuit and not the charging side, and your machine no longer has the battery side connected (hence, the requirement to fix the HOT LEAD!). I'd get this done before running it again or you risk burning out the stator and regulator as well. Why? Ask someone who can read a schematic.

I'm not sure why you think its a ground wire. My solenoid wire is black, but it carries +12 direct from the key. The solenoid is grounded through its attachment to the carb. On mine its a spade lug that pressed on a flat connector on the bottom of the solenoid. If that connection broke loose it would almost certainly ground itself somewhere nearby. It's all METAL around there!

The knocking is probably from the starting fluid. I recommend not using it to my friends, but encourage its use to my enemies ;) . What you're hearing is the engine dieseling on the ether and knocking the crap out of it.

The oil may be from the recently added dose (my be overfilled) or the engine may be toast. Fix the carb wiring and positive lead, get it running and see what other parts fall off. Just kidding. It'll probably be fine.

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Thanks for the info guys. So that solenoid under the carb is a fuel shutoff?, or does it ground the ignition? I'm going to dive into it tomorrow. I have a spare engine, which, I suppose would be the easy fix for me, but I don't want to use it if I do not have to. Rather build a wood splitter..heh
The solenoid is energized whenever the key is in a RUN position. On most machines, you can hear it "click" when you turn the key. It allows fuel to flow thru the carb when running. When the key is turned OFF, the solenoid deenergizes and blocks fuel flow. It helps eliminate run-on by positively blocking the fuel supply path. If it isn't energized, the engine just will not start or continue to run (unless it's defective and blocked OPEN).

The ignition is normally grounded through the key switch when in the OFF position (or by the interlock wiring if you try to dismount with the deck engaged, parking brake not set, etc.,). It must be opened to allow the magneto system to supply high voltage to the spark plugs.

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ah, ok. Thanks alot. I did notice the clicking when the key switch was turned on.
Ok, I fixed the battery lead. It Appears that solenoid on the bottom of the carb was cooked. The 2 wires leading to the plastic connector, nor the plastic connector were hurt or burnt. The plastic from the solenoid itself was burnt. And the burnt plastic appeared to me as if it were a burnt wire casing, the way it bubbled up. I'm off to the local john deere dealership to pick a new solenoid up.... ugh
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