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Old 08-04-2009, 12:59 PM   #1
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Angry OFNA FORCE .26

First af all let me say this may be out there somewhere but I am new to this type of forum stuff.
I have purchased a Ofna Ultra LX Comp and i can,t get it tuned. I am looking for the factory specs on the needles as far as number of turns for both of them. or a recommended number of turns if someone has better luck with that. It was used and they guy didn't know what he was doing. it has ran before but then I blew a servo for the throttle and it hasn't tuned since then. I took it to the local hobby store and we got it running good but once it got warmed up it shut down and wouldn't restart. Now it will start until I throttle it. I have spent more time looking at this than bashing it. this is my 2nd Ofna 1/8th scale and the other one ran great right out of the box. Can anyone please help me with this.
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Old 08-04-2009, 01:57 PM   #2
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First I need to know if it's a two or three needle carb. On that mill if it's a three with a mid-range needle, it's a little tricky. Also if it's been sitting for a while the O-rings on the needles have gone to poo. Check the OFNA web site, they have a lot of info on it.
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Old 08-04-2009, 03:08 PM   #3
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I believe that it is only a 2 needle. it only has 3 adjustments, low speed, high speed and the adjustment for the carb stop so that it can idle.
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Old 08-05-2009, 11:59 AM   #4
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High speed neeedle 3 turns out from closed and low speed is a half in from flush.
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Old 08-10-2009, 01:44 PM   #5
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I got my car running but it is extremly hot. i am not sure were to go from here. I am told that it runs best at temps around 200. what do i need to do to make this happen?
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Old 08-10-2009, 04:08 PM   #6
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What are your needles at now, you may have your low speed too lean it should not be more than a half a turn in from flush.
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Old 08-10-2009, 06:23 PM   #7
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Here's the manual incase you don't have it already. Pretty bad manual, but it's covering both engines so yeah guess it has to be a bit general.

http://www.ofna.com/pdf/eng-force25-26.pdf

Anyway, when you say engine is hot, does that mean at idle, or while running full throttle?

If it's idling hot, then chances are it's idling at a high rpm, to adjsut this you need to adjust the idle screw (turn the screw anti clockwise to reduce idle speed), and then you may need to readjust your Low speed neddle too (clockwise leans the fuel, anti clockwise richens the fuel).

If it's running hot while your full throttling the car, then first thing would be to richen up your high speed needle (the main brass needle.. again, clockwise leans fuel, and anti-clockwise richens). So richen it about 1/16th and see how it goes.
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Old 08-14-2009, 10:03 PM   #8
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Try tune from a rich mixture which is more turns out on high needle. Slowly lean it till it start coming to life and responding faster.
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Old 08-16-2009, 09:44 AM   #9
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From my previous experience with that particular engine, it is going to run fairly hot and is not going to hold a tune at all. I think the carburetor is the major downfall of that engine. Good luck, look on OFNA's website for base needle settings, although I recommend you replace that engine with one that is easier to tune and holds a tune. An Ultra Comp 2 was my first 1/8 scale buggy as well. Decent buggy overall, although front end design seems to put a lot of stress on upper turnbuckles causing them to break very frequently. I still have the car with alumnium steering knuckles and a few other mods if you would want a parts car.
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