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Old 06-21-2008, 06:30 PM   #1
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Default os 18 tm

when i let off gas it idles high for a few seconds then it goes down. the servo is not binding. also if i get it to run right it runs bout 300 degrees. it's in a revo and i've tried a a3 and a 8 plug. i got a a5 but i have not put it in yet. i have a new clutch in it. a m2c three shoe.i also put new pads and washers on slipper clutch. when the idle don't come down it's not high enough to engage clutch but it's noticable higher. the motor has a gallon and half of trinity 20% through it. any suggestions on what my problem is? thanks
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Old 06-21-2008, 10:33 PM   #2
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please help.
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Old 06-21-2008, 11:10 PM   #3
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I thinkn the OS A3 plug should work for ya, it sounds like your bottom is too lean. try to fatten up the low speed needle an hour at a time till the idle evens out. Then tune for temp on the top.

you could allways just go back to factory settings and start from there...
flush on bottom and 1/2 turn in from flush on mid/top.

Hope that helps!
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Old 06-22-2008, 08:58 AM   #4
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thanks i'll try that in a minute. the motor is new put could it be wore due to the 300 temp it has been to? i always get piston to the bottom when i cut it off but i just womdered if the temp could have damaged it. the pinch feels good tho.
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Old 06-22-2008, 10:09 AM   #5
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before running your engine again give us some info..how many tanks has it had as is it done with break in if not then that 300 temp might have hurt it but it might still be ok..


if you idle is reving up like that richen your low speed..


you always tune your high speed needle first for temp then your low speed needle as it changed ur temp very little..


after reading your thread though im thinking you might have a air leak as this same thing happened to my .21TM where to get it run good it was running high 280's or 290's and getting it back down it had no bottom end and i found out my exhaust coupler was broke..id check simple stuff like hole in fuel line, bad exhaust coupler or even leaky carb
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Old 06-22-2008, 10:09 AM   #6
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ok so went i went out and checked. the bottom was flush. but i noticed that when i shut motor off i can hear it sizzilin at plug. also when you gas it hard out of a corner it hesitates like it's lean but if i richen it up it won't hardly run either. now one thing i need to mention is that when i first bought this motor new i had to take carb off cause the throttle stuck half throttle and when i got it apart it seemed like the needle was bent. but i messed with it and got it freed up. sometimes do you just get irratible motors? this is my second os motor and the first one was a breeze and still runs good. the first one was a os 18 cvr.
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Old 06-22-2008, 10:12 AM   #7
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i have a os .18 cv-r a os .21tm and just bought a V-spec speed..

which needle was bent because you could have very well messed it up and need a new carb..also when you took the carb off you could have caused a air leak
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Old 06-22-2008, 10:16 AM   #8
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i'm almost done with second gal of fuel. i've checked the coupler and the very tip does have a tear in it but i think it is still sealing off. but i'll get one today. thank you so much for your help.
i didn't run any special fuel when i broke it in. is there a break in fuel? sorry if that sounds dumb i just don't know. i've ran trinity 20% the whole time.
at one time there was a hole in my fuel tank but i got a new one now.
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Old 06-22-2008, 10:20 AM   #9
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if you take the screw that adjust bottom all the way out that needle was bent. i was very careful went i took it off and put it back on. i don't think i messed it up but it's possible.
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Old 06-22-2008, 10:23 AM   #10
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no there is no such thing as a break in fuel

they recommend u break the engine in with the fuel your gonna rune but in my .18 i broke in with odonnel and then switched to sidewinder which i broke my .21tm in with and now switched to byrons gen2 so it doesnt matter on fuel except its always been same percent for me

my exhaust coupler on my revo was very small and was where it zip ties onto the header and the tear was actually under the zip tie..replaced it and it was break

im betting you have a air leak more then anything..ill try to find a thread on how to check for a air leak in your carb as ive never checked but you can get this goops to seal it up for like 10 bucks and a lot of ppl do that to there brandnew engines just to make sure they stay sealed..

also are you running a pull start or a backplate because you could be leaking air there
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Old 06-22-2008, 10:32 AM   #11
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here i found you a how to on checking for carb leaks..also has some great tuning stuff


http://www.rchobbies.org/engine-tuning.htm
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Old 06-22-2008, 02:33 PM   #12
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thanks for the help. i'm running a tiger start. i didn't make it to hobby shop today but tomorrow i'm gonna get the coupler from the head to the header. tonight i'm gonna do that leak test and see if any of that is leakin. should i hear that sizzlin noise around plug?
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Old 06-22-2008, 05:54 PM   #13
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ok so i put the fuel line on and blew in it, oh yea i took the tiger drive off. well around where the crank comes out of the back plate it bubbles really bad there. but my question is where should the air come out? it just seems to me that the air has to go somewhere. thanks
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Old 06-22-2008, 07:09 PM   #14
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ok so i took fly wheel off and that bearing is leaking like a seal. is that my problem?
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Old 06-22-2008, 08:13 PM   #15
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man it seems you got some problems.. a small leak around the back plate area i dont think will hurt to but i know people seal them up and as for the bearing it sounds like you might need to install a new one..

you can by some carb sealer off amainhobbies and use it on the carb and backplate..the sizzling around the glow plug might just be from it being to hot or the glow plug might not be in all the way..i dont think thats your problem right now so i would worry to much bout it and just work on sealing the carb,backplate and probably changing the bearing altho id wait till end for that as they can be a pain
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