damiles

I have an OS 70 SZ on a Raptor 60 and am running Cool Power 15% fuel. Does any one know the approximate settings for the carb?

Right now I have the low speed a little rich from center, the high speed at about 1 and 3/4, and the mid range at about ¾. The engine seems to have good power on the high end but hesitates while getting from idle to mid range. Once it is at speed it seems to be fine.

Raydee

My Feedback: (3)

http://www.osengines.com/manuals/70sz-h-manual.pdf

Try this link to the online Manual.

REDNOSERAPTOR

Hi There!

it sounds to me that your mid may me be lean for the mixture your using, although I think you should have left the low needle alone unless you have had problems starting the motor, I have two OS70 and I never had to richen or lean the low you should know that the slightest movement of the low needle makes a difference on this motor. the mid needles factory setting is 1 turn from closed. is the engine new? because if it is you may still need to run it alittle rich untill it comes alive set the low and mid back to factory setting and work from there. I also use 15 % coolpower and it runs very well for me.

damiles

Thanks for the information. I'll leave it at factory settings for now.

Filipvdm

Hi, I also have an os 70 on a Raptor 60. Although it seems to run fine, it drains the tank very quickly. Can someone tell me how long they run with one tank (I don't know the size of the tank, but I think it is the standard one that comes with the kit)
My low speed needle is far of from the center with mine and I think it is still too rich.

misileman

My Feedback: (8)

I get around 10 minutes on a tank depending on what type of flying I'm doing. The stock 60V2 tank is 500cc, the 90 fuel tank will fit in the 60V2 and is 550cc. Just make sure to rebalance the machine for the 50cc more fuel load. I use the 500cc stock size.
My needle settings on the 70SZ are; low end 10 degrees leaner from screw slot in line with carb centerline
mid range needle is almost 1 full turn out from seated (11:30 if needle was a clockface)
high end can vary due to temp and humidity but usually ranges between 1 3/4 to 2 1/4 turns out from seated (in)
The OS70SZ has been the engine least effected by temp & humidity (more humidity than temp usually) than any of the other OS engines that I own (37SZ, 50 Hyper, 70SZ, 91SX C-spec pumped), its a very user friendly engine.
One note, from what I've experienced the 30% nitro fuels hold needle settings more consistantly than 15% or lower nitro levels. This doesn't mean that if you use 30% fuel that you never have to readjust, you just don't have to adjust it as much in value.

Shiny side up, optional.....
Mike

Filipvdm

Waw, only 10degrees. Mine is almost 45 off center and as I said I think it is still too rich. I am a beginner and at the hovering stage and still only manage to do 8 min with one tank.
But thanks for your reply, I will compare it to my settings.
Man, this engine tuning is a time consuming part of the hobby. At least for a beginner

Filipvdm

By the way, do you need to loosen the mixture needle stopper (part no 7 on the exploded carb. drawing) when you adjust the mixture needle? The manual does not mention anything about this.

misileman

My Feedback: (8)

You should not need to loosen anything to adjust the carb. The low end screw (as per the manual) needs to be turned past the adjustment your taking it to and then turned back. For instance to lean, turn the screw a little bit past where you want to set it (counter-clockwise) and then clockwise back to your setting. This is for the low end screw only.
Use the low end to adjust your idle/start up. Too rich it will flood easy and not idle consistantly, too lean and after a flight the idle will be too high. Never mess with this setting unless the engine is warmed up. Ideal setting is easy to start & idles consistantly.
Mid range setting is mid stick operation and should not require alot of adjustments because the "High End" setting effects this too. Basically getting good smoke and throttle response around mid stick and hovering.
High end should be the most used adjustment and the first one you try before changing any of the others unless it won't start, then refer to the "Low end screw" (assuming you exhausted all other starting troubleshooting first, ie. glow plug, glow plug extension, ect.).
Once you get the engine broke in and the sweet spot setting found, it's just a few clicks (high end needle) in for high humidity or out for low humidity. Mine runs the same setting from 45 to 85 degrees out, it's when the humidity goes from 45% to 95% is when I need to adjust it. I haven't had to touch the mid or low end adjustments since it was broken in. I've changed them but ended up setting them back to where they were and changing the high end.

It will click and become part of the routine of the first tank of fuel on every outing.

Let me know how it goes...........
Mike

Filipvdm

Thanks again Mike,
Yesterday after reading your reply, I checked on my needle settings. To my surprise I discovered that the mixture needle is only 1/4 away from fully open. That might be the reason all my fuel seems to evaporate in a minute. However the engine seems to run fine in my opinion, but then again I am a beginner. But it starts from the first turn, idles stable and accelerates good. There only seems to be a hole in the fuel tank. Maybe I need to lean the mixture and enrich the medium and high speed needle. high speed is a bit more than 1 1/4 open and medium speed 3/4 open.
It seems I am going to have to play around with it a bit more.

misileman

My Feedback: (8)

Glad to hear I could help you out.
The OS70SZ isn't as economic as the 61WC which I could get 12 to 15 minutes of flight time with but was not much of a power house like the 70 is.
Also put your finger on the bottom (crank case cover) of the engine after a flight and check to see if it's running at temp. You should be able to hold your finger on it for 3 to 5 seconds. If the engine is running cool, then start leaning it down a click or two until you start to get some heat in it. This will help with flight times per tank and also give a little more performance, these engines will still run pretty smooth when running rich, the temp test will help dial it in. I usually run mine so that I can only hold my finger on it for just over 3 seconds. When checked with an infrared temp gun, it's around 220 degrees farenheit (at the glow plug). Which is a good temp.

Hope you enjoy the hobby of heli flying as much as I do.
Mike