Hello, I used to race 1/10 touring cars and always used OS engines. A monkey can tune an OS engine and get it to run. I then went to airplanes and they are even easier to tune. Now my neighbor brought his Exceed RC Extreme 4wd off road buggy he has owned for a year and never got it running. I have gotten it to run and have been carefull to keep it rich as to give the engine a chance to break in. I can't keep it running though unless I leave the glow ignighter on the plug. Even then the engine wants to bog down if I go to full throttle. The fuel is a year old so that might not be helping of course. So any tips you have please share. Regardless of my previous experience go ahead and spell it out as if talking to a complete newbie, except I at least know the names of all the parts and the difference between the high and low end needle valves The engine is the .18 CXP, never heard of that before, with a rotory valve carb and dual mixture needles....

<span style="font-size: small;"><span style="font-family: Comic Sans MS;">Hello there. In my experience, the best thing to do would be to get rid of the stock engine and get something else. I know that this thread has the potential to become a 'brand basher', and it has no need to. The bottom line is, get a new engine since Exceed's stock engines are not that great, possibly a new gallon of fuel, and get that buggy up and running. </span></span>

That would be an easy call if it were mine and my money. My neighbor may not want to spend $140 on an OS .18 CV as I would.

Needing to keep the glo-driver connected is probably an indication the carb is set too rich. A new glo-plug is might help, but I'd lean the HSN a bit until it runs without the glo-driver. It should be still rich enough for break-in. The LSN may need attention too, but typically the factory setting for the LSN is never too far away from the final setting.

I am certain the LSN has been adjusted. My neighbor has claimed that honor. I read that the factory setting is to make the needle head flush with the carb barrel. It is out a bit from there so it is likely loading up at the low end. So, I have compensated by going too lean on the top end I suspect (1.75 to 2.0 turns out) hense why it takes off, when the igniter is attached, then stumbles and tries to die out if I go to full throttle (running out of fuel). It will stay running in a low/mid range without the igniter.

watch these 2 videos they will give you all the info you need to learn how to tune. I don't know how many times I watched them when I was first starting out.

http://www.youtube.com/watch?v=oSmMzpZM_As
http://www.youtube.com/watch?v=BJFsJAxNoRg

Car engines are harder to tune because the only way to tune for higher revs under load is by driving them. Assuming the plug and fuel are good, open the high speed needle to a quite rich setting (or what you'd consider to be very rich). This ensures that at idle then only the idle needle will be controlling the fuel. Start the engine and slowly lean out the idle mix after it's warmed up for a few seconds. If the revs start to drop you'll know it's too lean so go the other way. If the revs start to rise as you lean it then you'll know it was too rich so keep going until the revs begin to drop then richen it back up a little. That'll give a reasonably accurate idle setting.

Now you'll have to drive it to get some load on the engine when you open the throttle. Open the throttle very slowly and listen to the engine and also watch for smoke from the exhaust. Ideally the engine should be running quite rich when the throttle is opened enough for the high speed needle to come into play (roughly around half throttle). If it sounds like it's 4 stroking with lots of smoke then it's rich so bring it back and lean the high speed needle a little and try again. For running in, the mixture you want at full throttle is where it's just barely got into a clean 2 stroke but a bit of 4 stroking sound is fine. At this stage you're not looking for instant acceleration from idle, that can come later after the engine is run in, so give fairly slow movement on the throttle.

If this still doesn't work for you then it's likely to be either a bad plug or bad fuel, maybe even both. Given the problems you're having I'd be inclined to fit a new plug first (preferably a hot plug) and then get or borrow some fresh fuel to try.

I second on the hotter plug. They tend to help the stubborn/ worn engines.

After you borrow the fresh fuel make sure you give it back when you are done!!LOL
sorry downunder I had to say something!!
good advise, I have alway gone the other way and started with the HSN and then the LSN but the way you described it may actually be an easier way to fine the tune. I will have to give that a try.

Well, the engine is getting better. I expect it just need to be thouroughly broke in still. It has less than 6 tanks though it. I am taking my neighbor to the LHS today and will likely recomend he picks up a few plugs ans some new fuel. I need a spur geer for my Jato 3.3... something about repeated and sustained wheelies Now that engine runns great!