New Buggy with OEM Battery Issue

[Bluexrx]

I ordered my Trailmaster 300 XRX last-month from Moto-Buys, my first ever Go-Kart. Anyhow, ordered it on the 5th and received it on the 12th. Set it up several days later and fired it up. Had a difficult time getting it started, but was able to run for 6-10 minutes on 3 occasions before it overheated and shut down.
Then, after several days of not being able to start it, it fired up again. I ran it around my house for two miles. After that it wouldn't start again for two-weeks. I removed and cleaned-out the carburetor, reassembled & remounted it today and sure-enough it fired up!
I ran it for a mile or so before realizing that the red-light (overheat) light was on again and shut it down. After two hours I attempted to start it again, and nothing. Turn's-out the battery is dead. I had always noticed that whenever I attempted to start it during those previous two-weeks, the "Battery Tender's" red light was on, just from the starter engaging. Should I replace this battery, or might it be a component failing to re-charge it while it runs?
Any suggestions/recommendations from experienced Buggyist's, would be very much appreciated...

Thanks in advance..!

[Gummerfan]

Did you do the assembly/setup yourself? Did you have to fill the battery? Was it fully charged initially? You may have a short somewhere thats draining your battery. I have a 300xrx and if you run it at low rpms for a long time with the lights on, that can drain the battery. Other than that I don't know.
The overheating thing concerns me. The only time mine has ever redlighted was during a prolonged period of low speed operation. (we were poking along a mountain trail and my wife was looking for rocks for our fish pond),and even then it was just a brief flash, but picking up speed and getting some airflow cooled it right back down.I've heard some owners have had trouble with bad temp sensors, you may want to check that.
Hopefully Sycarms or somebody with more knowledge can chime in.

[Bluexrx]

Yes, I had it delivered directly to my home and performed the set-up myself. I filled and performed the initial-charge as well. During the 20 minutes or-so that the buggy ran yesterday, I did my best to vary the speed I drove it at. Initially though, it sat idling inside my garage for 5 minutes. When I noticed the overheat-light (Red) I turned around and noticed that the fan was on.

I decided to take the Battery to Auto-Zone last night to have it tested, and they confirmed that it was no-good.
I replaced it with a new Battery while there, brought it home, made sure it was at full power and connected it to the buggy. When I turned the key, nothing happened. No ignition, and the starter never engaged. The horn and lights won't work either so now I'm completely stumped.

I suppose it's an electrical issue, but I don't know where to begin troubleshooting. Any advice from those with electrical experience would be very much appreciated.

Once again, any suggestions are appreciated...
*Just checked the buggy this morning and noticed the red-light glowing on the Battery Tender. Seems as though it was drained while connected overnight.

[Bluexrx]

Recharged the battery. Replaced the thermo-switch with a new one. Located a loose connector and secured it. Buggy fired-up so I put two miles on it before the red (overheat) light came on again.
Pulled it back into the garage and shut it down. Then I turned the ignition switch on, and nothing, again. No ignition, lights or horn which puts me right back where I started with it.

Any educated guesses would be welcomed, and thanks in advance for any feedback..!

[SYCARMS]

Is the battery connected correctly? It's common to reverse polarity especially if the replacement battery was reversed. Make sure you have pos. to pos. and neg. to neg. Not sure why your overheat light come on with the fan. Have you checked the coolant level. China ships their buggies with alcohol based coolant which you do not want for it induces corrosion. Drain the coolant and replace with a high quality glycol based coolant.

[Bluexrx]

Battery polarity is correct. I will be changing the coolant, as I was unaware of the alcohol-based product it arrived with. Thanks for the heads-up...

[SYCARMS]

Get your volt meter and start checking at ign switch. If it is a 5 wire switch you should have one wire with 12v all the time. Turn the key on and wire to ign. should show 12v, then turn the key to start and the wire to solenoid should have 12 volts. Now you have to be careful with the cooling system for it air locks very easy. Many even at the factory will fill until coolant is at neck. If an air bubble forms which it 90% of the time does the coolant will appear to be full but the air pocket will keep the coolant from circulating and the engine will overheat. When filling pour very slowly stopping often to allow the air to escape. If this is not done air will be trapped in the system and will not be able to escape. With the radiator filled just short of top of fins and cap off start and run engine until it reaches operating temp then shut off and let cool then check and add coolant barely to top of fins and repeat until fluid stays constant then top off to bottom of neck and lock cap down.

[Bluexrx]

After the buggy ran last, I removed the rack above the motor in order to check each of the electrical connections individually. And while browsing older posts from former 300xrx owners, tried to learn of the issues they'd experienced. I disconnected each of the multi-wire plastic connectors and applied a small amount of dielectric grease to them, and re-crimped all of its bullet-connectors.
I cut off the glass fuse casing and soldered-in a micro-fuse holder in its place. Not being able to read any numbers I referred to the manual to find the fuse amperage, which it clearly stated to be 10 Amp. I purchased a pack of 10 Amp micro fuses and put one in the new fuse holder installed on the buggy.
I buttoned everything back up again, turned the key and still had no response. This went-on for the next several days, causing me a lot of frustration. While reviewing the electrical diagram, I couldn't make out the amperage written above the fuse, and decided to take a closer look at the original glass fuse. Sure-enough, with a magnifying glass I was able to read a one-five/250V. I replaced the 10 Amp fuse directed by the manual with a 15 Amp fuse, turned the key, and the speedo-light immediately illuminated.
I also took the time to replace the coolant, with a quality glycol-based product. Once it actually fires up I hope to resolve any air-lock issue that may exist (thanks Sycarms). Although the starter engaged when I tried to fire it-up, I quit trying after a dozen or-so attempts. 100 degrees ambient temp, and didn't want to cook the starter...

[SYCARMS]

Unless you had a bad fuse 10a or 15a should not make any difference. All my buggies weather 150 or 250 use a 10a fuse for the ignition. My Blade kept blowing the 10A fuse and since on a ride only a 15 was available. After installing it the next occurrence was burned wires. It turned out to be a bad ground from in the electrical box to the cvt cover which grounds engine to chassis. I replaced the ground to engine directly from the battery.