engine trouble

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basher2

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i have an O Brothers 27.2 race ported reed motor thats just been rebuilt. I broke it in with 1 tank idle. I took it out to get it tuned, but had no luck. It is pretty much sounding like an overheated nitro engine. here is what it's doing.


1/ it start and runs. but there is this strange sound comming from the engine as though there is a loose screw and washer vibration noise.


2/ it can take off but then after a few seconds at high speed it starts getting sluggish as an over heated nitro motor would.


3/after getting it up to high speed it seems to lose power. when i then bring it to a stop it stays reved up for a few seconds before going to low idle.


Engine pros pleeeese help me out. thnx
 
your tooooo lean. check your plug. its probly dark grey. pull your high speed needle out about 1/8 of a turn. since you cant go by tempts like on a nitro you have to go by your plug. do some high speed passes and see what color the plug is. it should be a chocalate brown when running right
 
also. idling a 2 stroke for a full tank will foul a plug. swap it out if thats the case. lots of folks run the balls off them for the first tank with a rich mix. it gets the ring seated really good
 
i'll run it 2moro give it my best shot, and if it still does the same i'll take pictures of the plugs and post them.
 
ya, thats from letting it idle for so long. the top of your piston is probly black too. id clean it up a little and run the balls of it. hows it running now?
 
Yep The Tyop Of That Piston Is Black As Heck. Is There A Liquid Solution That I Can Spray In There And Drain Out? Or Do I Have To Diassemble The Motor?
 
i would just pull the head off and steel wool it. but don't step on your feet either. nothing bad will happen if you just run it out. lots of folks will go thru a break in period with these motors wich is just fine, but just as many will tell you to run it rich and balls to the wall for the first 2 tanks, then lean it out, then keep rollin like the cops were chasin ya.. remember not to over tune.. once you got it going it will be fine till the weather has a drastic change and even then will still be just fine. i came from nitro so tunning and break in was a big deal for me. i couldnt figure out why i lean seized 2 heads and kept blowin thru plugs. then someone told me to quit messin with it. a plug should last many gallons and tuning is just to look cool at the track.. good luck and let me know how its running. sean over at o'neills is a great guy. he has another mill comin his way shortly. think im going with th 27.2 as well. it has a good ratio of high rpm and torque as well. well good luck and let know what happens
 
kryptonite said:
i would just pull the head off and steel wool it. but don't step on your feet either. nothing bad will happen if you just run it out. lots of folks will go thru a break in period with these motors wich is just fine, but just as many will tell you to run it rich and balls to the wall for the first 2 tanks, then lean it out, then keep rollin like the cops were chasin ya.. remember not to over tune.. once you got it going it will be fine till the weather has a drastic change and even then will still be just fine. i came from nitro so tunning and break in was a big deal for me. i couldnt figure out why i lean seized 2 heads and kept blowin thru plugs. then someone told me to quit messin with it. a plug should last many gallons and tuning is just to look cool at the track.. good luck and let me know how its running. sean over at o'neills is a great guy. he has another mill comin his way shortly. think im going with th 27.2 as well. it has a good ratio of high rpm and torque as well. well good luck and let know what happens
Click to expand...
tuning it with a 1/8 or 1/16 turn is important...if your running in dust, the air filter will start to gunk up and a 1/16 lean will bring the top end revs back


but if i am on a clean track or street or just starting with a fresh filter it needs to be richer.... ie...dirty air filter = less air:cool:
 
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