# Craftsman wont start



## Nathan Pierce (Mar 26, 2020)

I have a craftsman dyt 4000 and I can't get it to start. I've checked spark, fuel,compression and valve clearance and everything is good. I was using it the other day and was fine and then went out the next day and noticed the battery under the hood was laying on its side and battery acid spilt and the only thing that it got on was a few wires which I cleaned and ohmed them out and all good I'm lost on what else it would be


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## pogobill (Jan 31, 2012)

Welcome to the forum Nathan Pierce. Are you getting fuel into the cylinders? What sort of trauma did your tractor face, to have the battery flipped over under the hood?


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## Nathan Pierce (Mar 26, 2020)

Yes I'm getting fuel in the cylinder and the battery doesn't have a hold down it just sits where the battery goes and where I parked it is on a hill so I'm guessing when I stopped it it fell over


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## Nathan Pierce (Mar 26, 2020)

Also I've tried starting fluid and pulling the plug and adding fuel and still nothing


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## pogobill (Jan 31, 2012)

What kind of spark are you getting? Also, did you cross the plug wires by accident?


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## Bob Driver (Nov 1, 2017)

The theory is Fuel/Air/Spark and it's supposed to start... What that leaves out is compression. Old timer once told me "Once you mix it, you've got to mash it"

"I've tried starting fluid and pulling the plug and adding fuel and still nothing". Is it getting "mashed" enough? Compression?

Have you put a fresh plug in it? Grounding a spark plug to the block and getting spark tells you the ignition is working. It doesn't tell you if the plug is actually firing in the cylinder properly under 8 to 1 compression. It takes an in-line spark tester to detect a weak, oil soaked plug. $5 Harbor Freight....


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## pogobill (Jan 31, 2012)

"Once you mix it, you've got to mash it"

A good way to remember that portion of the process Bob.


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## Bob Driver (Nov 1, 2017)

Yep... The guy had his charming way of putting things. He also once pointed out that "50% of all Doctors graduate in the lower 1/2 of their class".

One of his favorite questions was "If you're so smart, how come you ain't rich?"


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## Nathan Pierce (Mar 26, 2020)

Yeah I checked everything and everything is work exactly like its supposed to which is why I can understand why it won't run and yes I replaced the plug and checked everything. The only thing I haven't tried is to pulley the kill wire off the coil but with the kill wire on it I still get spark I'm lost and btw it's a craftsman dyt 4000 with a 18hp single cylinder Briggs engine


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## Bob Driver (Nov 1, 2017)

I missed how much compression you said it had?


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## Nathan Pierce (Mar 26, 2020)

Its almost at 110


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## Bob Driver (Nov 1, 2017)

OHV engine? The reason I ask is that with fuel/air/spark it should start, or at least "pop, especially with starting fluid.

So what could make it not start after parking it on a hill steep enough to tip the battery over? MY mind goes to an OHV engine with a valve setting loose enough that the intake push rod has come out of the rocker seat, is cocked, not allowing full valve opening, or throwing the intake valve timing off.

You say it's got 110 PSI, but that just tells you the valves are at least partially closing on the compression stroke. It doesn't tell you the push rod travel is enough to take a full fuel charge into the cylinder, or that intake valve is opening at the right time on the intake stroke. Push rod could have come out of the seat and bent when you cranked it.

I'd pop the rocker cover off and check the intake push rod. It's the aluminum one on a Briggs (that's why they are easy to bend). Sounds crazy, but you seem to have taken a trip into the Twilight Zone with this one, and what do you have to lose.


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## bbirder (Feb 26, 2006)

Have you checked the flywheel key?


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## Bob Driver (Nov 1, 2017)

bbirder said:


> Have you checked the flywheel key?


Good call... Rarely see a sheared key on a belt drive, but maybe the reason he parked it on that steep hill in the first place was the 10" stump he hit on the way down and by the time he regained consciousness he didn't remember it.

Happened to me once with a limb on a dirt bike and trying to figure out why the bike was laying in the creek and my chest hurt so damn bad...


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## wjjones (May 28, 2010)

Bob Driver said:


> The theory is Fuel/Air/Spark and it's supposed to start... What that leaves out is compression. Old timer once told me "Once you mix it, you've got to mash it"
> 
> "I've tried starting fluid and pulling the plug and adding fuel and still nothing". Is it getting "mashed" enough? Compression?
> I bought one years ago it is a very handy tool. And cheap so it's a win win.
> ...


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## Nathan Pierce (Mar 26, 2020)

I've checked the key and is good. Also checked the push rods and looks good too. I've been using the mower to drag a pallet to smooth my yard from where I had someone grade it last week with a dozer and was trying to smooth out the track marks. Also the hill wasn't that steep just a slight hump in the yard I probably had the batter tip over from running over the track marks all day and haven't noticed it until it wouldn't start and seen battery acid all over the wires under the hood


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## bbirder (Feb 26, 2006)

As Bob suggested, have you changed the plug? I've had new plugs out of the box fire against the block but would not fire under compression. If it won't pop with starting fluid, it can't be getting fire in the cylinder. Can you describe what wires the acid attacked? It's very difficult to get all of the acid out and it continues to corrode internally. This drastically destroys conductivity. Even tho you say you ohmed the wires, i feel you probably just checked continuity.


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## Bob Driver (Nov 1, 2017)

OK... Here's the bad news. That 31p777, 18.5 Briggs Intek is about as simple as a small engine gets. There are only 5 wires that go into the engine wiring harness. Of those, the only one that could possibly have any effect on the engine not starting, as you've described in your 6 post on this thread (From battery acid?) is the magneto kill wire. It would have to have corroded the mag wire to the point where it is grounding somewhere, but you keep saying you have *SPARK*... That eliminates that scenario as a possible cause from just battery acid getting on the wiring as you've described.

Beyond that in the trouble-shooting process it becomes a mechanical issue and it's highly unlikely a simple battery acid spill would cause a mechanical issue. Fuel delivery, compression, valve timing... People have covered most of that in this thread and you keep saying "Nope I've checked that"....

The Service Manual for that engine is posted in the Manuals Section of this forum, but it sounds like you need help beyond what most guys on this forum can provide (at least me). Here's the Briggs Tech Service # 1 (800) 444-7774, if they can't help you, you're screwed

Good luck.....


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## Nathan Pierce (Mar 26, 2020)

Okay I finally got it to start I pulled the kill wire off the coil and started right up. So what should I do to fix that just leave it unplugged or fix it?


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## pogobill (Jan 31, 2012)

Is it still out there running?
I'd fix it. Perhaps you could get away with a button switch or the like, wired into the kill wire, that would shut your unit down when you are done with it. Something to make it easy. glad to hear you got it running.


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## Bob Driver (Nov 1, 2017)

_*"Yeah I checked everything and everything is work exactly like its supposed to which is why I can understand why it won't run and yes I replaced the plug and checked everything"*_..... 

Your definition of "Checked everything" and mine must be slightly different, especially when it comes to "getting spark"


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## wjjones (May 28, 2010)

If you unplugged the kill wire, and it started I'm thinking it's the ignition switch. I have had 2 different craftsman tractors that I had to replace the ignituon/ key switch on. Or the other possible culprit would be 1 of the safety switches. While your at it just to be sure give the brake bar a peek underneath, and make sure it's lining up with the safety switch. If it's out of whack it won't depress the switch for starting. There's a tab/ flat piece of metal on there to depress the safety switch button.


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