I have a 10-year old rider mower with a 18HP Briggs engine. The way
it behaves mystifies me, and I wonder if anyone can suggest what is
going on.

First of all. the original battery refused to start the mower (even
after charging) after a few years, and I replaced it with a match even
though it cost some $60! Then that battery did the same thing after
another two years and so I replaced it with a cheaper battery from
Lowes. It worked fine after I hack sawed the battery compartment to
accommodate the larger battery. After two years it wouldn't hold a
charge, so I bought still another (of the Lowes type), and it is in
there now.

Having said that, I should add that all along, with all the batteries,
when I would leave the mower unused between weekly mowing's, I would
consistently find that the mower would not turn over. Since the
voltage reading on the batteries read low, I assumed something was
discharging the batteries. So I installed a switch on the battery
cable to enable me to disconnect the battery completely whenever I am
not using the mower.

That didn't work. Even though the battery voltage was holding at 12+
volts. the engine would not turn over. I found that if I connected my
10A charger just for a few minutes, the engine would turn over and
start. It's almost as if the battery needed a 'boost'. To me the
engine is acting as if it is semi-locked, and requires a strong
battery source to overcome its initial inertia. The first turn-over
always sounds like a real struggle, but if it makes it then the
subsequent engine revolutions seem easier for the engine. Then I
could then cut my lawn. Even if I turned the engine off as I was
mowing, I could re-start the mower.

This is getting exasperating! Yesterday, I charged the battery with
my 10A charger until the battery showed 12.3V. Then I left it
overnight with my trickle charger connected. This AM the battery read
12.4V. I cut the lawn (2 hours) and then checked the battery. It
read `14.1V! This tells me that the mower alternator (?) is working.
I left the mower off for two hours (with the battery cutoff switch
OFF), and the battery voltage was 13.3V!

Right now, it is some 4 hours later - the battery reads 12.3V and the
mower starts, but with its usual reluctance.

I have rambled here, and for that I am sorry. I hope I have described
things correctly. I am at my wits end as to what to do. I feel that
I could connect several batteries to get a strong start, and I'll
betcha that would do it. But golly. I can't do that.

Help

Duke