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  1. #1
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    Help with used T-Maxx

    Hello Guys,

    I bought a used t-maxx 2.5. It seems to be in great shape but I don't know how to check it out. Right off the bat there is something wrong with the receiver battery box. I put new batteries in the tx and rx but the radio doesn't respond. While checking the battery connections on the receiver I noticed there seemed to be a short. The battery box was warm. I messed with the wires and got the radio to respond but am not satisfied. I order a replacement battery box and switch and will see if that fixes the issues. The t-maxx has an easy start, I just need to get a battery. What is the best way to try getting this thing running? I have no history of what fuel was used prior. I'm not sure of the logical order I should proceed. Thanks for any help.

  2. #2
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    Never buy a nitro car without seeing it run and drive unless u have good experiance fixing them... with that being said I suggest u hit YouTube and start watching vids on running and tuning. While the traxass nitro was the most reliable out of my nitro trucks their is a learning curve to keep em tuned and running well... but have fun they are great fun. I have all electric now but still don't match up to the sound of nitro

    Sent from my SM-G950W using Tapatalk

  3. #3
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    Too late!!!!

    So anyway is there a guide on tuning the 2.5? I'm looking for a step by step guide to set up the carb.

  4. #4

  5. #5
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    With the above find a good you tube video. Tuning is done by both ear and hand...

    Sent from my SM-G950W using Tapatalk

  6. #6
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    Thanks guys. I am diving into the deep end. Looks like I need a few parts to get thing running. I need to replace the carb housing. Found one online and ordered it with all the seals needed. Also need a battery box and switch for the receiver. My switch was bad the the battery box corroded and did not make a good connection. Found this cheap online so I am replacing it instead of trying to repair the original. After these parts arrive and are installed I should be ok. I checked the links above and also found a few others on youtube. Rebuilding the carb seems straight forward. Can't wait for the parts to come in.

  7. #7
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    For the battery box issue, check the wires. Might just be stripped wires that are touching, and since there are only two wires, + and -, should be an easy fix. is the Radio 27mhz or 2.4ghz? if it's 27mhz make sure it has matching colored crystals. If it's 2.4ghz you'll need to find a tutorial on binding it. To get the thing actually running, well go to the 4 basic needs of an engine. Compression, gas, air, and for a nitro heat from the glow plug. (Would be spark instead of heat for larger 4-stroke engines). Make sure carb and air filter is clean to make sure you have fuel and air. if you're lucky enough to have your air filter disintegrate like mine did when i got my T-maxx, just start it without for now. As long as you don't run it too long you'll be fine for a second. To make sure it has compression, remove the glow plug, put a finger on the glow plug hole, and crank the engine. As long as it pushes and pulls your finger in and out, you're probably good. Finally, while the glow plug is out, plug the glow plug wire back onto it, put the end of the plug on the engine head, and crank the engine. you should see the coils get orange and hot. If all four of those things are present, the engine should be able to get running. It's all tuning after that.

    Oh, and for the ez-start, you can run it on a 2s lipo. Not gonna say it's the best idea, but it's what I'm doing since I really do not feel like spending $ 20 on a 6-cell 1800mah NiMH. Seems expesnsive to me, and the 2s lipo does the job, so I'll stick with that for now. Anyway, have fun with your truck! I got my T-maxx from a friend about a year ago. he let me have it for free, and it's been interesting. Engine was so gummed it was seized when I got it, so if it already turns without excessive force, you should be able to get this truck running again.

    And one last thing in response to Crock...
    Never buy a nitro car without seeing it run and drive unless u have good experiance fixing them
    But why not??? That's the whole fun of it, fixing an old nitro RC and seeing it come back to life. I wouldn't have enjoyed my T-maxx nearly as much if I knew it ran when I got it, lol.

  8. #8
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    Hey RC N3rd (cool name), I like the last part of your post. It's so much fun to buy something used or broken and bring it back to life. I love tinkering with things.

    So I've been pretty busy. I took most of the truck apart just to clean it up. The battery box for the receiver has a short somewhere. It is pretty corroded and the power switch is iffy. I found them online for $5 bucks and locally for same. So this is a no brainer to replace. I did clean up the original battery box and got power to the receiver. Radio is the older 27mhz but works. I bit the bullet and bought a nimh battery for the ez start and 20% nitro and extra glow plug. I took the carb off and cleaned it up real good and only adjusted the high speed screw. Took off the glowplug and it tested good. Shot wd40 in cylinder head and turned the motor over with glow plug out. Seemed ok. Put it all back together, added fresh fuel and I got the motor running!!!!! Runs alittle rough. The carb has had better days. The high speed adjustment screw has stripped threads in the carb housing which doesn't let it seal tight. I've already ordered one and will swap all parts over. The truck does run and the radio does control it. It spits a butt load of gas out of the muffler. Probably related to the carb issue. So anyway I am having a blast at messing with this thing. I can't wait to run it hard. It sounds like it will scream.

    So in conclusion, I bought a used nitro truck that needed a little tlc. I probably would have been better off buying brand new one for more money but where is the fun it that? I love the smell of nitro in the morning!!!!
    Last edited by Jack10525; 02-12-2019 at 08:51 PM.

  9. #9
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    Hey RC N3rd (cool name), I like the last part of your post. It's so much fun to buy something used or broken and bring it back to life. I love tinkering with things.
    Thanks! It is tons of fun, and sounds like you really enjoyed it.

    Cool to see the engine runs, but not surprising. It was surprising when my engine ran after being seized with gunk for probably 10+ years. Sucks the carb is messed up, but guess that happens sometimes. Once you get the new carb and dial in the engine, this thing should be a beast! Can't wait to hear of it actually driving.

  10. #10
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    Ok so I rebuilt the carb and got her running but am having issues keeping it running. I set the carb back to factory settings but they don't seem to work. I had to really add quite a few turns to each screw. It runs but rough and stalls a lot.

    Also the radio cuts out. I have the old style 27 mhz radio. It works but seems to lose signal frequently. The receiver antenna was cut so I soldered it back together. Wonder if this is causing signal loss. Should I try soldering in a new antenna, buy a new 27 mhz receiver or upgrade to a 2.4 digital radio?

    youtube video or motor running

    https://youtu.be/69dlyPtmJUk
    Last edited by Jack10525; 02-16-2019 at 02:03 PM.

  11. #11
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    Oh I forgot to mention the radio was getting alot of interference. With no radio input the steering would turn and twitch. Also my real car has a power hatchback that closed several times on its own. I think there is something really wrong with the radio.

  12. #12
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    Crystals crack or go bad. Go with a 2.4 ghz system.
    The Super Derecho

  13. #13
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    Yeah if the radio is that bad, just go 2.4 like Double G said. 27mhz just isn't worth fooling with that much. At least the engine seems to run nicely. If it keeps cutting out, try to drive around to warm it up, and then make adjustments to your idle speed. Get it fast enough that the engine won't die. Also make sure your high speed and low speed needles are allowing enough fuel for the engine.

  14. #14
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    swap out the controller. first thing when i had my nitro's as the old 27's are just to unreliable when going that fast.

  15. #15
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    Well this thing is fast becoming a money pit!!! I am uncovering all kinds of issues. The radio system is definitely needing replacement. I got the motor running better and decided to take it for a run. Runs like a beast!!! But It seems the radio cut out and I lost control at high throttle and hit a wall. Only managed to break a lower control arm but I can safety wire it on for now until a new one arrives. Bent several shocks and popped a couple of ball joints off. So a new 2.4 Ghz radio has been ordered along with the control arm and some extra screws. Hopefully after this I will just need to buy gas.

  16. #16
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    How do your receiver wires (servo wires) route through the traxxas receiver cover? My wires seem to be pinched. There is no opening to route them nicely.

  17. #17
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    Well this thing is fast becoming a money pit!!!
    LOL!!! Coulda told ya that. As a former E-maxx owner, and a current T-maxx owner I am very familiar with the MANY shortcomings of this vehicle. Don't think it'll be long before you find yourself wanting to upgrade bulkheads, shock towers, skid plates, shocks, and diffs. These are all very weak on the T-maxx and Emaxx, and I'm honestly surprised you didn't say your bulkheads broke from the runaway. My bulkheads are all completely trashed right now, from very little beating. Rear diff is ruined. All common problems. Just thought I should let ya know, not to deter you, as it can still be a very fun truck. It's just important to know what you are getting in to because it is A LOT.

    Also for the servo wires, haven't found a better way to route them. I just feed them through the stock hole in the receiver box and it's good enough for me. Not a huge concern. If you find it is pinching the wires more than you want, you could always widen the hole with a cutting tool of some sort.

  18. #18
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    Again, thanks for the comments N3rd. Wow did not realize all the things you listed were weak points. I'll be upgrading/replacing as things fail also long as I can afford it. Yep I will try widening the receiver box hole. Got a few days before parts are here. Can't wait.

  19. #19
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    Sounds cool, and yeah the Maxx trucks have a lot of weaknesses so you'll have fun fixing those. Can't wait to see what kind of beast you turn this thing in to. Also, if you find a cheap diff upgrade that's stronger than stock, PLEASE let me know. Haha

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