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Dark piston

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B

bplakers

Gone - bye bye.
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I just rebuilt my motor and over the weekend I broke it in. Tore it down today and the piston and cooling head were real dark brown like it was getting to hot. According to the temp gun temps never got over 250. What could be causing this? I had to run it a little rich to get it to stay running.
 
what color fuel are you running?? and there is another problem when that happens I just can't think of it at the moment..
 
Traxxas 20% blue. It still isn't running right. It wont idle unless you keep the idle out further than 1-2mm. If not it dies when you brake. On a traxxas 3.3 carb the settings are 4 1/2 turns out on hsn flush with lsn right? I hope it something simple because I just put 300 into this.
 
4 turns out with the HSN is stock setting, flush with the inner barrel of the carb slide valve is stock for the LSN.

Did you make sure to install the piston with the cutout portion of the skirt facing the front/carb side of the engine? If not, you should check as that would be relative to your symptoms.
 
youp its in the front. Hopefully something will work. Idk what else to do I've watched youtube videos tried to tune it off them. Tried to tune it off the sheet on here. Nothing seems to work or I'm just to stupid to get it right.

---------- Post added at 5:30 PM ---------- Previous post was at 5:26 PM ----------

Well I guess I can't try it one of my rods broke that keeps the back wheel straight. Just put new ones on.
 
Without a 1mm or less idle gap you will never get a proper tune. Set the idle gap to 1mm making sure it does not close past that gap when you apply the brake and tune the HSN/LSN from there starting at the stock settings.
 
you might have your lsn to rich because if that is too rich then gettin an idle is damn near imposible, the only other thing I can think of is that you have an air leak, and yeah a dark piston and stuff means to rich (the black is extra fuel not burning all the way i deleive) but yeah try the lsn try and lean it just alittle bit you might have it out further than you think I have done that before myself leaned it and the idle screw worked again,
 
alright I'll try that when I get my rod ends. Or do you know how to get the outer ones off? I just tried to switch it with my old one and it just kept turning and turning and wasn't going anywhere. It twisted right off the inside one . Outside ones just spin and spin. If i knew how to get them off I could replace it with a old one I have here.
 
it might have compressed passed the point of unscrewing.. if you get it off it might be stripped out.. I bought a couple things of those things for that reason.. they are cheap and it helps!!
 
yeah but they are acually still going the same way if you were to cut the rod in half and put them next to each other you would have to turn the things the same way. its always right to tight and left to loosen except on propane stuff...
 
mtaylortank said:
yeah but they are acually still going the same way if you were to cut the rod in half and put them next to each other you would have to turn the things the same way. its always right to tight and left to loosen except on propane stuff...
Click to expand...

You may want to re-think that :)
 
ok the only diference is that the inner ones are longer inner peice and the others haves shorter inner peices..
 
Adjustable Toe links/turnbuckles. One end is threaded with a right hand thread the other end is threaded with a left hand thread. Attach both rod ends to a fixed point, turn the shaft and both rod ends will either extend or retract on the threads at the same time depending on which direction you turn the shaft.
If both ends were right hand threads, one end would extend and the other retract at the same time.
 
got the link fixed thanks for all the help. Been workin 12's so I havent had a chance to test the motor. Back to 8s tomorrow hopefully so should have a chance to play with it after work.
 
It's still taking a long time to get it to start. Should the flywheel be turning the whole time while you're trying to start it with the ez start? I ran it around a little bit but it would bogg out and die. I didn't try to tune it yet. Going to have to do that tomorrow.
 
ok well most of my problems were prolly with the ezstart. I took it to quincy hobby center and the guy did a great job on it. It needed a new one way bearing and he rebuilt the carb. I had one bolt stripped out when I tried to get it to start this morning. Was prolly why it didn't want to run right. He also said for our altitude the HSN should only be turned out 3 turns. Ran it around a little bit when I got home and was running good. He made sure it started before I left the store. Was worth the hour drive. Was actually going there to swap out my rebuilt motor for a power up with traxxas. So he could of got me for a new motor but didn't.
 

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