# So I can't jumpstart a lawnmower



## SarahFair (Jun 10, 2014)

The battery is dead on my lawnmower from sitting in the 'on' position after a week. 

I was reading how long to charge a battery before it'll crank because jump starting off the bat isn't working when I kept seeing, "if you jump start a lawnmower with a car it can cause a battery explosion and blind you"


Really?


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## KingTiger (Jun 10, 2014)

Some mowers use a 6 volt battery, that wouldn't play well with the 12 volt battery your car uses.

Most chargers have separate 6/12 volt settings.


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## kmckinnie (Jun 10, 2014)

Maybe, maybe not. I use the 4 wheeler to do it.


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## SarahFair (Jun 10, 2014)

Well I don't have a 4-wheeler lol

The SO tells me to do it,  he has to jump start things on a daily basis,  so he'd know I guess. 


I actually got it to start and move but now it's revving kind of high and I can't get the deck to engage. 
I checked the little "pull out to push" bar and that was normal,  so? 

It also won't restart without being jumped off again.
It won't even act like it wants to start. Silent.


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## Da Possum (Jun 10, 2014)

Buy a new battery?


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## NCHillbilly (Jun 10, 2014)

I've jump-started mowers many, many, many times with no explosions so far. I would make sure it's a 12-volt first, almost all of them are.


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## prydawg (Jun 10, 2014)

most atv/lawn mower/jet ski batteries are pretty well dead once they get drained down like that. It is probably time to replace the battery.


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## Backlasher82 (Jun 10, 2014)

The charging systems aren't strong enough to charge the battery if it's dead, it's just enough to replace what was used starting it. If the battery sat completely dead for very long it may be sulfated and won't take a charge but I would try charging it overnight before I gave up on it.


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## SarahFair (Jun 10, 2014)

hdm03 said:


> Buy a new battery?


Don't get me in trouble! 




I think the battery was replaced recently. 


If it was completely dead it wouldn't even start and run,  right? 
Why won't the deck engage?


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## chadf (Jun 10, 2014)

Tell the S.O., To get out there and handle it......

To vague of post to help......


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## The Longhunter (Jun 10, 2014)

Backlasher82 said:


> The charging systems aren't strong enough to charge the battery if it's dead, it's just enough to replace what was used starting it. If the battery sat completely dead for very long it may be sulfated and won't take a charge but I would try charging it overnight before I gave up on it.



This.  You need to charge the battery.

It won't explode.



SarahFair said:


> Don't get me in trouble!
> 
> 
> 
> ...



No.  Your car battery is completely competent to crank the mower,  once it's cranked, the mower doesn't use the battery.  You can take the battery out, and it will keep running (DON'T DO THIS WITH YOUR CAR).  If you look, and take the cowling off the motor, you'll see that you can hand crank the motor (with a rope) with no battery.

Don't know why the mower won't engage.  If I had to guess, I'd guess that there is some sort of electric take off/solenoid that requires a fully charged battery to engage.

Lawnmower batteries don't hold a lot of juice.  Plus they tend to go bad fast when they are completely dead (at least that's my experience).  Depending on your personal frustration level, I'd follow backlasher's advice, and just get a new battery.

P.S. the high rev'ing is probably the motor's attempt to charge the battery.


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## StriperrHunterr (Jun 10, 2014)

SarahFair said:


> Don't get me in trouble!
> 
> 
> 
> ...



If you have a friend with a Battery Tender you could try that out, I know my NOCO smart chargers claim to be able to recondition, and desulfate the plates, but it sounds like it may just be gone. 

Of course, the deck not engaging _may_, since I'm not a lawnmower mechanic, be a symptom of the electrical system not having enough amps to take the load. I know that's what it would be in a car that dies when you turn on the AC or radio after it starts, or just doesn't stay running.


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## Crakajak (Jun 10, 2014)

SarahFair said:


> Don't get me in trouble!
> 
> 
> 
> ...


Most likely the seat safety switch isn't engaged.


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## SarahFair (Jun 10, 2014)

chadf said:


> Tell the S.O., To get out there and handle it......
> 
> To vague of post to help......


He's not available at the moment or id just let him handle it 




Crakajak said:


> Most likely the seat safety switch isn't engaged.


I hate that seat thing. 
I have no idea what's going on under there. Guess I'll do some googling and YouTube


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## modern_yeoman (Jun 10, 2014)

If the battery was dead it doesn't have enough voltage to engage the deck switch. Drive it around for a bit at full rpm and it should engage


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## Dog Hunter (Jun 10, 2014)

yep


modern_yeoman said:


> If the battery was dead it doesn't have enough voltage to engage the deck switch. Drive it around for a bit at full rpm and it should engage


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## NCHillbilly (Jun 10, 2014)

As several have said, if it's an electric switch to turn on the blades, it needs a near full charge to turn on. I don't know exactly why it won't do it with the engine running on a dead battery, but it won't. I jumped mine awhile back, and it took 15 minutes of running and charging before the blade switch would engage.


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## SarahFair (Jun 10, 2014)

Ill try that..


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## LIGHTNING (Jun 11, 2014)

The reason the blades will not engage is that there is an electric solenoid that operates a clutch to engage the blades. If you jump the mower off it will run but not engage the blades if the battery is weak. You will have to charge the battery to full if it will take a charge.


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## georgia357 (Jun 11, 2014)

SarahFair said:


> I kept seeing, "if you jump start a lawnmower with a car it can cause a battery explosion and blind you"
> 
> 
> Really?



Pay attention to the above.  When jumped off, a dead battery can explode  and battery acid can blind you.


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## Killdee (Jun 11, 2014)

Yep, a discharged battery can produce an acid gas that sometimes will  explode with a spark from the cables. This is why you are told to connect the cables to the dead battery first when jumping 1 off. I have seen first hand 2 car battery explode when cables sparked when being hooked up out of order. Riding mower batteries usually only last about 2-3 seasons before needing replacement.

If the battery is fairly new, old borrow a charger and try that first since it was cranking good before.


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## jimbo4116 (Jun 11, 2014)

Killdee said:


> Yep, a discharged battery can produce an acid gas that sometimes will  explode with a spark from the cables. This is why you are told to connect the cables to the dead battery first when jumping 1 off. I have seen first hand 2 car battery explode when cables sparked when being hooked up out of order. Riding mower batteries usually only last about 2-3 seasons before needing replacement.
> 
> If the battery is fairly new, old borrow a charger and try that first since it was cranking good before.



You can charge your Lawnmower battery using jumper cables and your car battery.

Here you go.

http://www.wikihow.com/Charge-a-Dead-Car-Battery


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## GoldDot40 (Jun 11, 2014)

SarahFair said:


> I think the battery was replaced recently.



I'd look into this. If it was, then it's possible that it's.....under warranty. Take it back and swap it!


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## rayjay (Jun 11, 2014)

It is possible to use the car battery just leave the car's engine turned off. A car charging system can zap a small battery with way more amps than the little batt can handle.

Plan B. Take out dead batt. Go to Wally. Buy new batt. $25. Go home. Install new batt. Cut grass. Finish. Turn off mower. Remove key.


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## firebreather (Jun 11, 2014)

Spend the extra money n buy an gel cell battery


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## fireman32 (Jun 11, 2014)

Batteries will EXPLODE! acid goes everywhere and it is Loud.  If it doesn't restart on its own after its been run awhile, the battery is dead. Replace it.


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