z425-briggs model 445577, 23hp

Got the valves set ,motor runs fine. I have changed the alt. under the fly wheel, the regulator and new starter. It is charging @ 13.5 and with full bat starts fine but after mowing for a couple of hours it will not turn over, put the charger on for 3 min. and it starts fine. Cked the bat and it was down. This is a new battery. The owner says this is the 4th battery since March. Need help.

Check power when the electric pto is on. Has to be a short somewhere.

Or power is being used for the PTO but alternator charge is not getting back to the battery. Broken ignition contacts, burnt fuse, broken ammeter, bad pto switch. These are all suggestions for testing only. I would also check all wiring for wear spots. I have no idea what is wrong with it.

With the battery fresh, it should test at about 12V. Engine idle, it should test at about 13.
5. What does it test at when the electric PTO is switched on?

First thing to do is check eng wiring harness & owners manual for a wiring diag of mower,some mod briggs eng have a inline fuse provided by briggs in eng wiring harness on alt(dc)output or mower mfg provided same in wiring harness.

IF you can't find fuse/blown fuse on alt output,check operation of ign sw,if alt output connects to battery thru ign sw,same may be going bad due to wear/vibration & alt output not being connected to battery internally in ign sw all the time when mower in operation.

Check new alt stator & old stator & see if you can find a pn on each,see if pn for each are the same,if you goto link below & lookup mod/type numbers of eng in briggs eng lookup you'll see four different pn alt stators & two different regulators used on your mod eng,if the DC output on new alt stator is less that orig stator or reg is not matched to stator you will have charging problems,also check that magnets in in flywheel ring aren't broken/missing & check size of magnets,depending on output amps of alt magnets were different sizes,you might want to pickup a service/repair manual for your eng from local dealer,briggs website or ebay,it will tell you how to id/troubleshoot charging system on eng,if charging system on eng checks out ok I would say problem in pto,ign sw or wiring harness on mower.
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