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bogging when hot

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maxxdout

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hi people,sorry me again,and thanks to all for the replies. One more problem. Runs great during the first few runs,after that very sluggish and wants to bog when giving throttle. If I let it cool it runs great for a bit and it soon looses power again. Engine not overheating,running at 230-280 f. This one is driving me nuts.Sometimes it won't go into second gear cause of lack of power.
 
you could be loosing compression. How many gallons do you have trough your engine?
 
about 10 tanks,not much

seems to be an ongoing problem with my 2.5
 
its seems to me it may be a worn piston sleeve because it only get bad when its hot what i suggest is tear down you engine take out the piston and the sleeve see if the piston moves all the way through the sleeve and look for scouring on the sleeve and make sure you tighten down everything real good when you put it back together.
 
should I just replace piston and sleve to eliminate this posiblity?
 
check first it wouldnt hurt because if thats not it you just went and blew around 50+ for nuttin
 
280 is kind of high. Richen up your high speed a little to attempt to keep the temps down and see if that helps.

I run my engines between 200-240 and I don't run into this problem anymore.
 
tried that but still does the same.My 2.5 runs better at that temp.
 
Is it possible you're running too rich?

Trying to learn from your experience,
bomber
 
Originally posted by olds97_lss
280 is kind of high. Richen up your high speed a little to attempt to keep the temps down and see if that helps.

I run my engines between 200-240 and I don't run into this problem anymore.

LMAO...280 is about the sweet spot for the TRAXXAS 2.5. That engine is engineered to run hot...or perhaps it was mistakenly engineered to run hot. Either way, the 2.5 is a hot runner. If you can keep it running nicely at 280, then you are doing well.

As for the cause of your problems, I concur on the sleeve and piston issue. It sounds like the temps are allowing the internals to expand beyond a good compression seal. Check the piston and sleeve for excessive wear.
 
Originally posted by SkyMaxx


LMAO...280 is about the sweet spot for the TRAXXAS 2.5. That engine is engineered to run hot...or perhaps it was mistakenly engineered to run hot. Either way, the 2.5 is a hot runner. If you can keep it running nicely at 280, then you are doing well.

As for the cause of your problems, I concur on the sleeve and piston issue. It sounds like the temps are allowing the internals to expand beyond a good compression seal. Check the piston and sleeve for excessive wear.


Really?? Then what happens after it gets down to half a tank?
I always thought that at the half way point on the tank the engine tends to run hotter it runs leaner. Correct me please if I am wrong. I say this cus if you are normally running at 280 then what happens when the half way point comes? The engine may jump into the 300 range.
 
You are absolutely correct, and that is why TRAXXAS engines are known for running on the hot side. A 2.5 running at 310 at the half tank mark wouldn't surprise me in the least.
 
won't that reduce the lifetime of the engine? IMO that is kinda cheap. no one wants to buy another mill if they can keep using the oem one. I myself will still keep using the 2.5 since it is the wifey's.
 
I don't think they engineered themselves to a short life cycle. I just think the engines happen to run hot. I have not heard of them having a particularly shortened life cycle. On top of that, most people solve the heat issue with aftermarket carbs, cooling heads, shims, exhaust, etc. Basically, people go out and hybrid up the 2.5 and it becomes a runner. Personally, I would just dump the mill and get a decent runner that doesn't require all the upgrades. Why? Add them up and you might find that the cost of the upgrades equals the price or damn close to the price of a decent mill.

Note: I am not saying that the 2.5 is a bad engine. Just stating that it runs hot and that the cost to bring the temps down might be better spent elsewhere.
 
got it. I will probably just buy an os engine . I am not sure of the sirio. I will see how the temps work on my maxx. THanks SKymaxx.
 
Originally posted by SkyMaxx
I don't think they engineered themselves to a short life cycle. I just think the engines happen to run hot. I have not heard of them having a particularly shortened life cycle. On top of that, most people solve the heat issue with aftermarket carbs, cooling heads, shims, exhaust, etc. Basically, people go out and hybrid up the 2.5 and it becomes a runner. Personally, I would just dump the mill and get a decent runner that doesn't require all the upgrades. Why? Add them up and you might find that the cost of the upgrades equals the price or damn close to the price of a decent mill.

Note: I am not saying that the 2.5 is a bad engine. Just stating that it runs hot and that the cost to bring the temps down might be better spent elsewhere.

It's deceptive, however, that TRX sells the max with an engine you'll immediately want to replace. Sure, it keeps costs down at the POS, but the bottom line stays the same and you end up with an engine you don't like. Not a good way to handle RTR (designed for newbs), not to mention a newb to the hobby. There's no excuse for sub-par quality. (I think I'm just venting about my own employer though, TRX is just takin' the heat. maybe THEY should get a bigger head)

Unrealistic expectations,
bomber
 
LOL...for the mass of average newbies out there who generally play with the truck and are happy with it, the engine is just fine. For those who make a hobby out of this and want to see performance from their toy, the disappointment you feel it appropriate. But, in this hobby upgrading, tweaking, tinkering, and in general modifying the RC is a huge part of enjoying the hobby. Sure it costs money, but in the end...seeing your modified RC doing crazy poop at your command...it is darn near priceless.
 
I still think that TMAXX2.5 is a great start for newbies. I am pleased with my tmaxx. I love screing with it and wrenching it. This is all part of the hobby. Yes you come to a bump but then it would be to easy and then boring.
 
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