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  1. #1
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    t-maxx 2.5runs off ground but not on ground

    I know nothing about nitro and have a question, I have always used eletric

    I was given a T-maxx 2.5 truck and when I give it throttle it will move a foot and die, but if I pick it up off the ground and hold it and give it throttle it will run no problem. So in the air runs but on the ground goes a foot and dies. I set the needles to factory settings.

    When truck was given to me it had cracked bulkheads and a broken a-arm. Man, those were fun to fix broken/bent screws.

  2. #2
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    Make sure the fuel tubing coming from the exhaust isn't nicked. Sounds like it's leaning and dieing. Also make sure the fuel tank isn't cracked, causes the same thing. These depend on the exhaust to pressurize the fuel tank and push fuel to the carb.

  3. #3
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    change out the glow plug and put new fuel lines on it, leak test the fuel cell... how does the compression feel in the engine when you turn it over by hand turning the flywheel "with the glowplug installed"...
    Traxxas is good, but so are other Manus

  4. #4
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    Sounds like a clutch issue to me, Check the condition of your clutch shoes
    and your slipper pegs while you're at it, just for fun.
    Bash, Crash, Upgrade, Repeat..

  5. #5
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    Quote Originally Posted by NitroTrout View Post
    Sounds like a clutch issue to me, Check the condition of your clutch shoes
    and your slipper pegs while you're at it, just for fun.
    well if his clutch was locked to the bell it wouldnt die itd take off and keep going... and on his spur it wouldnt die either it would either be really tight and work fine, or itd be really loose and just rev the engine and not move but still wouldnt make it die...

    pretty wierd issue for sure this op has..

    i think its a prob with the engine...
    Traxxas is good, but so are other Manus

  6. #6
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    I have the truck on its side and just noticed that the exhaust pipe is dripping a dark brown in middle and yellow on the outside liquid

  7. #7
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    Quote Originally Posted by razbus View Post
    I have the truck on its side and just noticed that the exhaust pipe is dripping a dark brown in middle and yellow on the outside liquid
    thats old gummy fuel, its prolly not burning the fuel very well, might be why it dies easily...

    you could just stick a new glow plug in and have a go see if its any better

    personally id tear the engine down and clean the hole engine incase there is a bunch just sitting in the crankcase and id tear the carb down and clean it as well. replace all the fuel lines, also id clean out the fuel tank to make sure there isnt more gummy fuel that will go right back into the engine when you go to start it after the engine/carb are cleaned and new fuel lines are installed. but thats just me i dont play around and will tear into any part of my RC's at the first sign of trouble...

    if you need help with something, visually, youtube is your friend for nitros, even if its not the same rc vehicle as you own most are very similar...
    Last edited by kuskye25; 03-15-2013 at 06:43 PM.
    Traxxas is good, but so are other Manus

  8. #8
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    Just got back from lhs and the guys there said I would have less headaches in the long run if i just got a Dynamite .19T engine. They said it is a direct replacement for mine and tuning will be easier because if it is gummy gas, then I will need to rebuild the engine and get a anew carb

    I did pickup the lines and stuff, is there anything that I could possibly add to the fuel to help clean out the engine

  9. #9
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    Quote Originally Posted by razbus View Post
    Just got back from lhs and the guys there said I would have less headaches in the long run if i just got a Dynamite .19T engine. They said it is a direct replacement for mine and tuning will be easier because if it is gummy gas, then I will need to rebuild the engine and get a anew carb

    I did pickup the lines and stuff, is there anything that I could possibly add to the fuel to help clean out the engine
    no additives that i know of for the fuel, as i said id tear the engine down and clean it with wd-40, you could use a dyna .19 i believe it is as they said a direct replacement "dont quote me but pretty sure it is". i doubt youd have to get a new carb on your 3.3, the engine/carb prolly just needs cleaned and a can of wd-40 will do it all, lot cheaper alternative then a $110 engine or whatever the dyna .19's are going for nowdays...

    however i cant guaranty you that cleaning your engine will fix it, it just seems from what youve said thats the issue, its possible the engine maybe be wore out i just dont have enough info.. unless i could personally mess with it and diagnose it..

    also use fuel and clean your fuel tank so it doesnt have gummy fuel in it either that will shoot into a new engine or a cleaned engine that you put back on the truck
    Last edited by kuskye25; 03-15-2013 at 08:21 PM.
    Traxxas is good, but so are other Manus

  10. #10
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    itll be good for you to tear down the nitro engine and carb, cause someday your going to have to do it eventually, i tear mine down for cleaning and maintenance every 1 to 2 gallons of fuel ran thru it, which if you run your truck alot can be a matter of weeks or days...

    and hey if you screw something up or you do all this and the engine is still junk buy a new engine, and youll have gained alot of experience and wont be as worried about tearing into one down the road...

    if you do just buy a new engine, then for sure rip the 3.3 down and mess with it, as itll jsut be sitting in a box anyway calling out to you saying fix me fix me
    Traxxas is good, but so are other Manus

  11. #11
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    I picked up new fuel lines, air filter, fuel tank and glow plug. If that does not work, I guess I will try my hand at cleaning the engine, and look at the slipper clutch as mentioned earlier. Wish me luck

  12. #12
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    Quote Originally Posted by kuskye25 View Post
    thats old gummy fuel, its prolly not burning the fuel very well, might be why it dies easily...

    you could just stick a new glow plug in and have a go see if its any better

    personally id tear the engine down and clean the hole engine incase there is a bunch just sitting in the crankcase and id tear the carb down and clean it as well. replace all the fuel lines, also id clean out the fuel tank to make sure there isnt more gummy fuel that will go right back into the engine when you go to start it after the engine/carb are cleaned and new fuel lines are installed. but thats just me i dont play around and will tear into any part of my RC's at the first sign of trouble...
    And since yout tearing your engine down anyhow, what a great opportunity to check your
    clutch shoes, and friction pegs, just for fun.

    Personally, I tear everything down and inspect every component after purchasing
    a used truck.
    You'll be surprised at what secrets your truck is hiding.
    Plus it's just good to know your truck inside and out.
    And there's plenty of exploded views and parts lists available here to help guide you.
    Bash, Crash, Upgrade, Repeat..

  13. #13
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    Quote Originally Posted by NitroTrout View Post
    And since yout tearing your engine down anyhow, what a great opportunity to check your
    clutch shoes, and friction pegs, just for fun.
    ................. +1 ive had to many bad experiences with used vehicles they always need a complete once over, and as usual there is always tons of stuff wrong or that doesnt come close to my standards at all

    Quote Originally Posted by razbus View Post
    I picked up new fuel lines, air filter, fuel tank and glow plug. If that does not work, I guess I will try my hand at cleaning the engine, and look at the slipper clutch as mentioned earlier. Wish me luck
    good luck man, even if some money gets wasted look at it as paying for experience, i do anymore... have a laugh and understand its all fixable in the end...
    Last edited by Double G; 03-16-2013 at 08:46 AM. Reason: merge
    Traxxas is good, but so are other Manus

  14. #14
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    Quote Originally Posted by kuskye25 View Post
    good luck man, even if some money gets wasted look at it as paying for experience, i do anymore... have a laugh and understand its all fixable in the end...
    +1 Well said buddy.

    razbus, the money you spent for new fuel lines, air filter, fuel tank,
    and glow plugs is money well spent in my opinion. You cant go wrong.
    Fresh batteries for your servos and fresh fuel are also very beneficial.
    Process of elimination buddy, goes with the territory when you buy used.
    If you're still having engine dying issues, you'll know its something
    further down the trough, like the engine
    as Kuskeye suggested... Did I mention the part about checking the shoes and...nevermind
    Bash, Crash, Upgrade, Repeat..

  15. #15
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    Haha, one way to check the clutch spring without pulling the motor, if it runs fine when handheld, and will idle fine, hit the brakes and see if it dies. If the spring is broken, it will. The reason being is, any engine rotation will cause the clutch shoes to spin out if broke, but if you hit the brakes in the air and it idles and the tires stop spinning, it's probably ok.

  16. #16
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    And don't forget to check the CB bearings, bad bearings can give the same effect as a broken CB spring, any hint of roughness in a CB bearing it should be tossed.

    http://AVIDRC.com has good bearings, & most are $1 so there's no reason not to stock up on commonly replaced/used up bearings.

    You can find the bearings dimension right under the Part# on the exploded view.
    Look out for the tree/crunch!

    LiPo? Naw NITRO!!

  17. #17
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    Quote Originally Posted by razbus View Post
    I was given a T-maxx 2.5 truck and when I give it throttle it will move a foot and die, but if I pick it up off the ground and hold it and give it throttle it will run no problem. So in the air runs but on the ground goes a foot and dies.
    All classic signs that the clutch is shot. If the engine will start when the tires are off the ground and spin while cranking that is a sign of broken clutch shoes or spring. If the engine will run fine as long as the truck is moving and will stall when coming to a stop that is a clutch issue.
    The Super Derecho

  18. #18
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    well at least if its only your clutch thats super cheap..., the few times i had a clutch lock up on me i was able to put the vehicle on the ground and gun it and make it go long distance, is why i wasnt thinking after 1 foot it dies was the clutch, but then again at least him tearing the engine down would have reviled the issue. thats what i love about tearing mechanical stuff down, your always like, yup theres my issue, once you get down to it
    Last edited by kuskye25; 03-16-2013 at 01:38 PM.
    Traxxas is good, but so are other Manus

  19. #19
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    I also learn how this truck works by taking it apart.

    Well I got the motor pulled out and took a few pics, in case anyone is curious.


    http://i1359.photobucket.com/albums/...psa1fb3482.jpg

    http://i1359.photobucket.com/albums/...psc9c23784.jpg

    http://i1359.photobucket.com/albums/...ps4004cb40.jpg

    http://i1359.photobucket.com/albums/...pse09c8c44.jpg

    http://i1359.photobucket.com/albums/...ps1c40f32d.jpg

    http://i1359.photobucket.com/albums/...ps1c7a2f79.jpg

    Found some good videos over on you tube on cleaning so I will try them out in a day or so.

    Once I go the engine cleaned up I will take a look at the transmission.

    I remember reading about making the transmission single speed and forward only, should I do anything like that. This is going to be foe me bashing around in the backyard, no racing or anything

    any idea what size the bolts are to get engine head off, not sure, need to order a tool, got nothing that long
    Last edited by razbus; 03-17-2013 at 07:00 PM. Reason: fixed links

  20. #20
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    That needs a very good cleaning and you may have an exhaust leak at the silicone adapter or even the head is not on tight or missing the gasket.
    Clean that engine up real nice.
    The Super Derecho

  21. #21
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    Quote Originally Posted by razbus View Post
    I also learn how this truck works by taking it apart.

    I remember reading about making the transmission single speed and forward only, should I do anything like that. This is going to be foe me bashing around in the backyard, no racing or anything

    any idea what size the bolts are to get engine head off, not sure, need to order a tool, got nothing that long
    you can make the transmission forward only, most of us on here have, not 1 speed just forward only.... a long 2.5mm allen wrench will take them head bolts out, they may make a loud pop when they break loose dont worry it didnt snap the bolt although itll sound like it...

    so you have the engine out how did the clutch look.... broken spring or shoes...
    Last edited by kuskye25; 03-17-2013 at 07:46 PM.
    Traxxas is good, but so are other Manus

  22. #22
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    have not looked at the transmission yet, maybe tomorrow. changed out oil in the shocks because they sounded real squishy like they had jelly in them. they feel much better.

    since I am going to be rebuilding the engine, should I treat her as a new engine and do the break in or just go ahead and tune it

  23. #23
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    Quote Originally Posted by razbus View Post
    have not looked at the transmission yet, maybe tomorrow. changed out oil in the shocks because they sounded real squishy like they had jelly in them. they feel much better.

    since I am going to be rebuilding the engine, should I treat her as a new engine and do the break in or just go ahead and tune it
    the clutch im referring to is on the engine behind the pinion gear/clutchbell, wanting to know if it was locked up or the spring broke

    break in is only for a new piston and sleeve, so unless your buying it a brand new one then no, just set her to factory settings and start it up... let if warm up fully then tune it...
    Last edited by kuskye25; 03-17-2013 at 10:54 PM.
    Traxxas is good, but so are other Manus

  24. #24
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    Going to work on engine at some point tomorrow, curious to see what this will lead to next. I am hoping it will be a cheap fix.

    please remember that I am new to nitro, always had electric, I hear clutch and head for the transmission.

  25. #25
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    Quote Originally Posted by razbus View Post
    Going to work on engine at some point tomorrow, curious to see what this will lead to next. I am hoping it will be a cheap fix.

    please remember that I am new to nitro, always had electric, I hear clutch and head for the transmission.
    ok cool man, i hear ya on the clutch part, now you got two clutches to deal with, hahaha
    Traxxas is good, but so are other Manus

  26. #26
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    oh the joy

  27. #27
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    Quote Originally Posted by razbus View Post
    I know nothing about nitro and have a question, I have always used eletric

    I was given a T-maxx 2.5 truck and when I give it throttle it will move a foot and die, but if I pick it up off the ground and hold it and give it throttle it will run no problem. So in the air runs but on the ground goes a foot and dies. I set the needles to factory settings.

    When truck was given to me it had cracked bulkheads and a broken a-arm. Man, those were fun to fix broken/bent screws.
    When you pick it up and the engine is running are all the wheels turning in the same direction... IF the fronts are going one way and the rears are going in another,,, you've a diff in upside down....
    Founder of H.U.A.
    Hop Ups Anonymous

  28. #28
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    all the wheels do turn in the same direction.

    I do not believe it is the clutch, what do you think

    http://i1359.photobucket.com/albums/...psfa40c0c3.jpg

    http://i1359.photobucket.com/albums/...ps06a30f49.jpg

  29. #29
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    Don't think it's your clutch.... But best thing to do is check you driveline by hand, check and see if anything is binding, bad bearings, something of that nature. If not that then there might be a sheared off pin in the tranny....
    Founder of H.U.A.
    Hop Ups Anonymous

  30. #30
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    just so you have some visual here is a pic ive posted on here many times to show the inside... these are the pins hes saying might be broken/sheared... ive had it happen a few times myself...

    yeah you clutch looks good, i didnt think that was the issue, but always good to check

    Last edited by kuskye25; 03-18-2013 at 02:35 PM.
    Traxxas is good, but so are other Manus

  31. #31
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    Thank you for the picture it will help. I got the motor torn apart today and picked up TRA5247 to redo the O-rings and seals on the carb because it is such a mess. I will clean the motor and carb tomarrow and put it all back together, then it will be time to pull the tranny for an overhaul

  32. #32
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    how tight should the flywheel nut on the crank shaft be, because I could not get it to come loose. I got everything else out but can not get that nut off too look at the bearings

  33. #33
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    Quote Originally Posted by razbus View Post
    how tight should the flywheel nut on the crank shaft be, because I could not get it to come loose. I got everything else out but can not get that nut off too look at the bearings
    Sometimes they have red locktight on them, boogers to get loose. If you don't need to, just leave it, which is what I would do.

  34. #34
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    The Super Derecho

  35. #35
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    Quote Originally Posted by Double G View Post
    That is what I was following to break this motor down, from what I can tell everything looks good - not going to worry about it

    I just pulled the tranny off the chassis, clean motor and reassemble it tomorrow and then rip into the tranny
    Last edited by razbus; 03-18-2013 at 07:46 PM.

  36. #36
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    yeah as long as the front bearing behind the flywheel passed a leak test i wouldnt worry about taking the flywheel off...

    if you do want to take it off heat will help break loctite loose...
    Traxxas is good, but so are other Manus

  37. #37
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    I will try to remember that. I got the engine back together and it feels like goon compression when I turn the flywheel by hand.

    Next is the transmission.

  38. #38
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    Took the transmission apart found no problems.

    Got her all put back together and took her out and she runs pretty good with traxxas factory settings. Once I get her tuned, I will load a video.

    So it must have been something with the fuel lines and tank because they all are brand new, I figure cleaning the engine and rebuilding the carb help out also, got a good learning experience.

    Thank you to everyone's help on this, I could not have done it with out your help.
    Last edited by razbus; 03-19-2013 at 01:36 PM.

  39. #39
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    excellent man... and yup never hurts to know your kit inside and out...
    Traxxas is good, but so are other Manus

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