Lawn mower battery

I have a riding lawn mower with a briggs & straton engine and when I try to crank it the battery will run down before it cranks and it has a full charge to begin with. What causes this to happen? The battery is new.

 

Does it sound like it's cranking up to speed ?
How long are you cranking it ?
Is the battery the same size as the previous one that was used there ?

 

It tries to crank, but the battery runs down before it cranks.
The new battery has more cold cranking amps.

 

Bad battery (even if it is brand new)
Starter bad/dragging

When you say the battery is brand new, is it brand new like you just put it in today & tried to start the mower for the 1st time & it ran down? Or is it brand new like you've been using it for two days/a week/a month & now its just today running down when trying to start?

Were you having the same problem before buying this new battery?

 

How old is the battery?

How do you know your battery has a full charge?

I would guess that the battery is bad. A bad battery can show full charge voltage but when a load is applied it quickly tanks.

 

The battery is a couple of months old. It started the mower on 2 different occasions and it was ok. Could it be the starter?

 

You say it starts to crank then fails to crank. Please clarify what's actually going on. Does it crank exactly one revolution and then stop cranking? Does it not crank even one revolution? Does it crank for several seconds and then stop? There are two well-known problems with some Briggs & Stratton engines that causes them to crank one time with a new battery and stop cranking. If that's the case then you either need a valve adjustment or the compression release mechanism has broken on your camshaft which will need to be replaced for cost of about 50 bucks. There is a test to pinpoint which of the two problems it could be.

 

My thoughts exactly, Airmark.