KM Problems

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Preacher

Preacher

Well-Known Member
Messages
174
Today I went to run my Baja for the first time in about a month (been super busy). That last thing I did was change the front plate on it. It starts up fine, but the idle is rather erratic. It will run, but even from a slow run will die when the engine reaches idle. Every time it does this it will restart on the first pull. I set the needles back to stock (I'm running the 990 carb). It usually will not run long enough for the engine to warm up completely. I got tired of tinkering with it tonight. Tomorrow when I get a chance I'm going to reset the needles to stock and just let it run. Could I possibly to be looking at an air leak, or just needing a tune? The last time I ran it the ambient temp was about 80 degrees. This evening it was about 60 degrees. Since new I have always tuned and ran it in hot weather.
 
check for air leak, make sure intake and carb are tight,,, not a big diff in temp,, but it is metal,, and things may shrink a tad when colder,, so may cause a little leak,, making it run erratic.., check your fuel lines as well,, the line I had in my tank was a ddm colored line,, and didn't notice until wouldn't run,, it blew up 5 plus times it normal size after being in the tank for some weeks and tore thru a hose clamp I had on it with the snappy rc kit and the fullforce high flow barbs ,, and fell off ,, just layed in the tank,,,
 
Thanks, I'll check that tomorrow. Keep the suggestions coming. I'm going to spend a few hours on it tomorrow.
 
I would definitely pull the air cleaner and check the carb bolts to make sure they are tight. The nice thing about these engines/carbs is they don't take constant tinkering like a nitro car does. You shouldnt really have to mess with the needles unless you are seeing a 40-50 degree temp drop, even then it would just be a slight tweak.

It also wouldnt be a bad idea to pull the plug and look at it since you have been messing with the needles. It should be a nice tan to dark tan color, if it is black do a couple high speed passes and see if it cleans off to tannish color, if not throw a new plug in, they are cheap enough.
 
Also check that the carb bolts aren't too long and causing an air leak. This can easily happen if your'e running a billet manifold with teflon gaskets. Had that happen on my rig. :)
 
I have checked everything and all bolts are tight. I took the needles back to stock setting and right now it is sitting and warming up. The idle is steady with a good deal of smoke. I'm going to let it run for about 15min (ambient temp is 55 degrees. Then I'm going to make an attempt to tune it. I assume that when I see a lot of smoke that the low speed needle is on the rich side and it needs to be leaned out a bit.

Update: the buggy idled fine, but when I attempted to throttle it died. Also noticed that it died if I applied the brakes or turned the steering wheel!!! Now I'm really confused.
 
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watch the obr video on you tube about engine tuning,,, will give u a good idea on how to do it properly,,, set needle to stock settings and if wont run,, turn up the idle a tad with idle screw,, once running, u can adjust the low needle to keep it running nice,, almost all of your adjustment will be with the high needle after that,,, if u are turning in the low needle to compensate for the smoke to lean it out,, you are starving the engine for fuel and probably wont run, or start,,,
1 1/4 turns out for low is a good starting point,, u generally compensate for the rich condition with your high needle,,, some chime in if im slightly incorrect,,, sounds like though u are leaning it out to the point of not running with your low speed adjustments,, and when u hit the throttle,, there is no fuel and engine dies,,, be careful running it to lean u can seize a piston to the cylinder I personally prefer some blue coming out the pipe as long as it will rev , that way I know its getting plenty of lubrication and engine lasts a lot longer
and here is another so u get a better idea on tuning,,
 
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I got it running strong and not dying when it returns to idle, but can't figure out why it dies when I turn the steering. OK. I was working on the problem with the steering and braking. I noticed that whenever I turn the wheels or apply the brakes the kill switch light starts blinking and kills the engine as if I cut the controller off. Any ideas? I have not done anything to the kill switch since I installed it and it was running fine.
 
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I thought I had a fresh charge on the battery. I'll charge it again tonight and if the problem persist, I'll pick up another battery.
 
I'm running the Killer Bee. I contacted Killer RC and was told that most likely the problem was that when I turned the wheel the battery voltage fell below cut off voltage and cut the engine. I'm charging the battery now, and will try again in the morning. If I still have the same problem, I can pick up a receiver battery locally and will do so.
 
Yes that why I asked that was happening to me once before I would turn left or right and the voltage would drop to low. I ended up having to get a new battery for my radio and not have had the problem since. Even when I would try different receiver batteries it would still cut off. If you would like you can read about Kent and I talking about it here below the video.


If you click on view the video on youtube you can see the comments.
 
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I checked, and I'm not even sure my charger was plugged into the wall all the way, so tomorrow will let me know if I need to buy another battery.
 
Got everything sorted. As was suggested, the receiver battery was weak (charger not plugged all the way in). I did that and charged the battery overnight (also put new batteries in the transmitter) and that did the trick. I got the tune straight and all is well in Preacher-land. Thanks to everyone for their help.
 
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