Need Help, 1974 Cub Cadet 129
 

I'm trying to get my grandfather's Cub running again. About 2 years ago when my Uncle was using it, it broke down, piston arm broke, so we got a rebuild block for the k301 engine, and had the engine repaired.
Now it ran fine for about 30 mins, then it started to act like it was running out of gas, but it had more than it needed. It would start but then it would act like it was running out of gas again, while trying to work this out that battery died.
Now the fun beings. I put a battery pack one it and it started, ran fine, so we thought just charge the battery. But today, just got back from trying to start it, ended up needing to but the battery pack on it again, it ran fine with the battery pack on, but when I took the battery pack off it stop running.
I think that proves it's NOT a fuel issue, but an electrical issue.
How do I track it down?
Is it the starter/generator or the voltage regulator? or something I have not thought of?

First, welcome to OCC..... :Welcome2:

This could be a number of things. Let's go for the simplest first. Charge the Battery up, then take it to an Auto Parts (or equivalent) and have the Battery "Load Tested". Battery weak, replace it. Battery OK, go back to the Cub. Report findings.

Thank you, Bedell for your quick answer.
some information i may have left out, SORRY.

The battery was brand new.

i will still get it checked out, because you can get a new battery that is bad from the start. and post what i find out here.
the only other stuff that has been changed, from what came with the tractor in '74 is the fuel shut off and the fuel line and one front tire.
also, the amp gauge on the tractor, never showed that the system was charging and it did not show it was draining the battery ether, just read zero.

that's all the information i have, i think.

Get it running again and check the voltage at the battery with it running.
Should show plenty of charge if the S/G is functioning as it should.
Sounds like a starter generator problem or a voltage regulator problem.

A good multi meter is handy to have and learn from.If you don't use the tractor much,a trickle charger and or a battery maintainer helps keep the frustration down when you jump on,turn the key,and nothing happens.Dont ask how I know.

Generator.
 

I second the use of a trickle charger. Here is my history on a 147.
70s, Add big tractor radio on hood, heavy draw for powerful radio
80s, generator fails, rebuilt and replaced voltage regulator.
90s, add 2 additional lights. (Tractor came with electric lift)
I can't keep up with electrical issues and always having a dead battery.
Give up on charging system and remove voltage regulator and several melted wires. Only have one wire to starter.
Put full size car (78 series) 750cca battery under seat plus the 350cca amp for the normally located battery. Remove amp meter replace with marine volt meter. Noticeable traction improvement from weight over rear axle
Put in quick attach plug on rear battery for trickle charger. (It also charges front battery)
Put charger on tractor every time I finish.
Batteries last 8 to 10 years.
Have not had a dead battery since conversion.
Run time: no lights or radio, close to forever. With just the radio, over 8 hours. Lights and radio over 4 hours.
Will run fine until voltage drops below 8 volts.

Thanks for your replies.
The battery checks out. The tractor will start, but I think it will just drain battery.
I need to get a multimeter, or new batteries for the one I have.

How do you check to see if the starter/generator is working, and to check to see if the voltage regulator is working?

thanks

Check the voltage at the Battery when the engine is running at WOT.

Remember and the fun beings, well lets say "still loads of fun to be had"

recap:
had battery load tested, V 12.7, load it rated at 150 tested at 147.so all good.

this morning:
started tractor, did not let run long, did not want to drain battery, did not have multimeter.

this afternoon:(after super)
used a multimeter check battery again, 12.7 V.
tried to start tractor, would not stay running, then need to add battery pack, still would not stay running, tried more than once, did have trouble getting it to start, also heard noise from near battery while turning over the engine, when engine would run the noise would stop. at this point i stop trying and came here to post this story of my fun to date.

also recheck the Voltage on battery, now at 11.7 V, and the battery pack needs to be recharged.
:bigthink::bash2:

Remove the ground cable at the battery. Now just touch the cable to the battery ground post and see if you get a spark. If it sparks when you touch the post you have got a short. Let us know if it sparks and we'll go from there