25 Motor Shot?

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pitbull14218

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I never owned a brand new motor before, so i dont know what to expect. Either way i own a Savage 25 I bought off ebay. It was all stock when i got it, at least the engine and suspension where. It was pretty dirty/dryed mud all over. I didnt really know what to expect but either way the way it sits now is it has a tune pipe.

I had a decent tune on it the other day and it was running the best i ever got it to. Now my buddy did the samething i did and bought his T-Maxx off ebay, he has the 2.5R motor, and his truck has stripped screws all over it, you would think the motor would be in worse shape then mine...... my buddy since he bought it never touched the Needles to tune it at all and his is WAY FASTER then mine even when i had the best tune i ever seen the truck have!

Now it was 19 degrees out today but i had it running good in colder conditions before. I wrapped the head and everything, i have a temp gun i try to get it around 220-270 degrees, i would figure it would run and not bog or just not be slow in that range but i wouldnt really know....other then not to be too lean because i know thats bad.

So today it kicked my ass the needles are so touchy, i couldnt get it to run like i had the other day.... i should of never touched them from the previous tune, but since my buddys was so fast i wanted to try to be faster.......

So what are signs of a shot motor? Or are all Savage 25's a pain in the ass to tune? I never really ran it in warmer weather i tend to get bored in the winter, so i use it then, and its a blast in the snow.

PLEASE HELP!!!! ITS DRIVING ME CRAZY!!!!
 
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samrsnow

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You need to seal the it with racers edge engine sealant.

I could give you more detail on how to seal an engine but for some reason i can't post anything from other forums...
 
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pitbull14218

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Are you talking about sealing the carb to the engine? I havent done that, its stock, that wouldnt be done on a stock motor? Are there any signs that show if a motor is shot?

Can people please help?
 

olds97_lss

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No compression with the glowplug in and the engine is cold.
Constant flame outs (dies while running for no reason).
Won't even pretend to start when hot.
Blows plugs for no reason.
Can't hold a tune to save it's life.

Sure fire way to tell is to pull the engine apart completely, take the sleeve/piston out of the engine and gently push the piston up into the sleeve. If the piston can easily be pushed so it is flush with the top of the sleeve (or sticking out), it's done and either needs replaced or re-pinched. Reason is, when it heats up, that fit between the piston/sleeve gets even more sloppy and allows the compression/bang from the combustion to blow by down into the engine and screws you your tune badly.

All that said, I'd try pulling the carb, clean the neck and crank case where it makes contact with alcohol, then get some high temp sensor safe RTV and put a decent coat all around the carb neck and insert it into the engine in the orientation that you need it for your throttle. Then, just as you tighten the cinch bolt, push down on the carb with your thumb to make a good seal and hold it while tightening the bolt. Then let it cure overnight. Reset the needles to factory and try again.
 

Scrogg

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All good advice but look at a few simpler things first.
Inspect the fuel and pressure lines. Replace them, they are cheap.
Exhaust gasket seal on the header could be torn.
19 degree weather is horrible on a nitro!
The HPI .25 is not a very powerful engine, quite boring to be honest.
That little 2.5r your buddy has turns a lot of rpms, way more than the .25 can. It is always going to be faster than your .25.
With a good tune it should be able to stay close to his truck until about 30mph, after that the the Traxxas is going to walk off.
You want to have some fun with your buddy, hook a tow rope between the two trucks and see what happens... The savage will drag it all over the place.:D
 

pitbull14218

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I thought maybe the design of the T-Maxx Tires where really bad or something because he has to feather his throttle or he just spins all four tires any speed he floors it on the snow. Mine i can floor it off take off it and its just so hard to get the motor to have any power down low, like i said i did have a good tune at one point and i was happy, but i thought it had more in it.

I can barely do a donut with my truck on this snow. My buddy does cyclones and flips with ease..

I guess i can try to reseal the carb to the motor.
 

pitbull14218

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Isnt the carb sealed to the motor stock though? i need to buy some RTV then. When i got the truck i put in new fuel lines with a fuel filter.
 

olds97_lss

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Traxxas chevrons suck in the cold. They are a good general bashing tire, but in the cold, you need something more floaty and sticky/soft so they don't get so rigid.

I run old school savage GT tires and losi aftershock tires in the winter. I run the traxxas chevrons as my basher tires in the summer.

Isnt the carb sealed to the motor stock though? i need to buy some RTV then. When i got the truck i put in new fuel lines with a fuel filter.
Yes, usually, but it's sealed with an o-ring that can deteriorate over time and cause leaks. Especially if you have ever loosened/rotated/taken off the carb. RTV on the neck is just a preventative thing that I do with pretty much all my engines. Even when new.
 

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