Help - 1872 won't start and might be eating batteries
 

I am new to all things mechanical and purchased a very used, but currently running 1872. After I got it home, it did not want to start. (It went Wah Wump Wah Wump etc. I kept at it, eventually the battery died and it just clicked) I fixed it with a new battery and new battery cable to the solenoid.

A few weeks later, same problem. Checked the wires - everything is still snug. Lights still work. Checked the battery volts and got 6.2. Hooked up a tender for 3 days. Checked volts again - 12.9 - but Still won't start. Solenoid audibly clicks, but the engine just goes wah wump, might sputter once, and then the pace slows.

Someone mentioned it might be grounding out, but I have no idea how to check for that.

Where do I start with troubleshooting this thing. I have zero skills, but want to learn.

- James
Woodbine, Maryland

check how much voltage is getting to the starter stud while cranking. make sure you're not losing power thru a connection.

I'll do that tonight. After i posted yesterday I went and looked at the old battery cable I took off and the plastic was melted and black at the battery terminal side. I don't know if that means anything or could have been caused when I first tried to jump the old dead battery. The new cable still looks fine.

Also, I noticed that on the solenoid there is a small red wire coming off the bottom right post that does not have a nut securing it in place. I have no idea what that is yet but plan to try and find a nut that will hold securely.

Regarding your suggestions, I assume I should be able to reach those posts by taking the metal shielding off from the side of the motor? Once I find the starter, do I check the voltage while trying to crank or just while the key is in the on position? Should the meter stay around 12v or is it normal to get a significant drop at the starter.

Also, would it be wise to try and jump the tractor from the starter posts or is that a bad idea?

Thanks for the help.

It means you had a "high resistance" connection. Possible causes are: loose, dirty, and/or corroded connection.

That is the power wire that energizes the Solenoid when you put the Ignition Switch into the "start position" There needs to be a nut on there and snug tight.

OK first thing I'd do if it was my tractor is to pull the engine out, remove the tins and give it a good cleaning. Then you can check out the starter. They are a major PITA to get at in the tractor. Look at all the electrical connections. Make sure they are clean and tight. Cubs are notorious for crappy electrical issues. Battery on an 1872 is under the seat and they run the ground cable to the frame. I'd run a ground from the battery right to the engine block. You can try a quick and dirty test to see if you have a bad ground problem by taking a jumper cable, connect it to the negative terminal on the battery and the other end to the engine. If it spins over the way it should then you know you have a crappy ground. OK maybe I'd do this before pulling the engine. If that doesn't do the trick then go for pulling the engine. Easy way to do this is to remove the engine with the plate that it's bolted to. Six 3/8" bolts that you get at from under the tractor. Two of them are up over the top of the axle. Don't be surprised if you find a mouse condo under the engine sheet metal like this one had.

Suggest that you download the service manual.
http://www.onlycubcadets.net/forum/s...ad.php?t=25397

Thanks for all the help so far.

I opened the tin covers, cleaned everything I could reach. It was mostly pretty clean.

I tried to jump the negative terminal to the engine without any change. I checked the volts at the post on the starter and it read 6v when cranking.

The starter is engaging the main gear/wheel thing and turning it, just not very fast. I also tried to jump the starter with a different battery directly. I think had I left it on, the tractor would have turned over, but sparks started to fly and it made some unnatural clunk sound (possibly the starter retracting?) so I pulled out. It definitely sounded like it was about to turn over though.

Soooo... I am figuring that I have a wiring problem, not a starter problem. I assume my next step is running new wire from the solenoid to the starter? I am looking at the wiring diagram and it looks like a straight run, but is there anything to look out for when I do it? I am hoping I can just pull the wire though the existing wiring shroud.

Is there anything else I am not considering?

Are you sure this thing hasn't tossed a rod or some other serious engine issue?
You may want to pull the spark plugs and see if you have compression on both sides. :bigthink:

Sam Mac - how do I test for compression? I did pull the plugs and made sure they were sparking (they do). It is possible I flooded the engine at some point I guess and I know that can screw up compression. But since the problem persists day to day, I assume that's not my issue.

Why are you thinking mechanic as opposed to electrical?

Because you said "and it made some unnatural clunk sound"