1872 starter and pto problem
 

I'm totally new to owning a cub and semi proficient in troubleshooting, but I sure could use your expertise. I picked up an 1872 gas cub for a song and really want to get it going. When I first brought it home, it wouldn't start with the key nor would it jump via the solenoid. I was able to put a jump pack directly to the starter to get it to start. I mowed my land with it and I was happy. Being lazy,I jumped the starter a week later and began cutting the grass again. After about 30 minutes I noticed that the the blades quit running. I thought I bumped the pto switch, so I attempted to re engage it with no results. Since I had been cheating to get it started anyway, so I figured that maybe the PTO switch had been my starting problem in the first place and finally the switch crapped out on me. Easy enough, I replaced the PTO switch. Still no good. I tested the seat switch and it has good continuity. I tested the brake switch and it has good continuity. I tested the ignition switch and it has good continuity in the off position, run position and start position. Any ideas?

What is the battery voltage with engine stopped? then running @ full throttle?
Should be 12.5 V. stopped and maybe 13.5-14 Volts running.
If not you have a charging issue.
Also look @ fuses
I don't have a wiring diagram here to see if you have a forward/reverse switch or if your system has a PTO relay that may be bad or???
All things for you to check.
You need to start @ the reason it will not start by following the power path through each component.:beerchug:

12.84 volts at stop and 12.84 volts running. Having said that, I sure could use some further help in determining what is associated with the charging system as I am ignorant on these. Thanks in advance.

I would be looking at your Ignition Switch. The Ignition Switch effects both the starting and PTO circuits.

Not sure where to start as it seems pretty expansive or a troubleshooting task. Any advice would be appreciated. I believe it's a charging issue.

Things I've replaced today and still haven't solved my problem: starter switch pigtail, starter switch, battery, starter selonoid. Tractor still starts when I put a jump box directly on the starter, but PTO still won't engage.

Did you get the correct switch for the 1872?

Yes. Ordered it from the cub cadet dealer. It showed up today. Still won't start with the key and PTO still doesn't engage.

@ this point it sounds like you are throwing parts @ it in hopes of winning the lottery.
Possibly you need to follow the wiring diagram, systematically eliminating each
circuit till you find the no power area and fix it.
This is not an electronic magic box thing, it is a simple electrical system.
follow the power till it stops and find out why and correct it.
Not trying to sound like a jerk here, a simple $5 meter and test light should do just fine.:beerchug:

yep need to chase the power thru all the switches and find out where its dropping out.