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Old Dec 17, 2012, 11:39 AM
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it seems like after every tank of run in, the max rpm could advance about 500, without altering the needles or very little adjustment.
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Old Dec 17, 2012, 03:20 PM
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Serbia, Belgrade
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Hello guys, i recently receive my engine and i need to know what size of propeler i good for break in this motor. Thanks in advance!!!
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Old Dec 17, 2012, 04:10 PM
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I think the manual suggests using the lightest possible prob, so that would be a 10*6 or 11*5. But the other guys know better.
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Old Dec 17, 2012, 04:33 PM
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Originally Posted by kentli22 View Post
I am using 11*6 APC, idle is 1/3 open at the Carb at about 2500rpm. how to make the fittings larger for the pump? what are the fittings of the pump?
Ok the 9cc engine is almost a .60 size or 10cc engine, so it tends to like to be propped like a 10cc or .60 engine. It behaves more like a .60 engine than a .45 engine.

It depends on your country and locale, But I used a couple of Dubro 8x32 fittings to replace the small metric fittings on the back of the engine crankcase and pump cover. For metric there are some 4mm size fittings that work well. You'll need to drill and tap (thread) the holes of course.






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Old Dec 18, 2012, 12:16 AM
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Istanbul, Turkey
Joined Aug 2004
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Kentli(any possibility to be a Turk?),it seems your LSN is blocking your spraybar to let HSN control at WOT.So my guess you should open LSN some more to allow your spraybar to work properly at WOT.My problem was same and after I changed the LSN with a SK50 glow engine LSN ,it seems better control.(I can have great WOT and very good,low idling without much spitting) but still some problems on fuel feeding while nose up.I remove the regulator needle and using only pump function.Added a return line to tank just before carb nipple.Also has a restrictor on return line.It seems I could have better results up to day.But still couldnt have proper field conditions to make a good work /test on it.
So I am thinking user firstly must change LSN profile and secondly try to have consistent fuel feed at all throttle spectrum.
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Old Dec 18, 2012, 02:26 AM
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Israel, Ramat HaSharon
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Quote:
Originally Posted by earlwb View Post
Ok the 9cc engine is almost a .60 size or 10cc engine, so it tends to like to be propped like a 10cc or .60 engine. It behaves more like a .60 engine than a .45 engine.

It depends on your country and locale, But I used a couple of Dubro 8x32 fittings to replace the small metric fittings on the back of the engine crankcase and pump cover. For metric there are some 4mm size fittings that work well. You'll need to drill and tap (thread) the holes of course.
Earl,


These pressure fittings are never the problem.
They don't have to allow a rapid flow of a viscous fluid; just very minute volume pulses of gas.
Even if the diameter of their holes was of its current size, it would suffice for this purpose.

For such a pressure fitting not to work at all, it needs to be completely clogged-up.
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Old Dec 18, 2012, 08:56 AM
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I have given it another try today. After running (idling) well for a minute it starts to form bubbles in the fluel line from pump to carb. Could not make it run decently after that, it would always go out after some seconds because of lack of fuel.

I did dismount the pump then, all ok, but on the other side, the regulator needle was stuck. The seat of this tiny needle is machined roughly, and so the needle gets stuck occasionally. I did smooth that out as good as i could (tiny stuff) with the blunt end of a 3mm drill. The motor did run like before after this.

Now to get perfect idle i have to close that needle quite a bit, and to get good rpm i have to reopen that needle. I think i should adjust the low speed needle. I think i should screw it in so it blocks the spraybar at idle? Sorry for beeing a noob.

Update:
After another regulator problem, needle stuck open this time, i have finally mounted a fuel filter. Maybe 3 year old weedwhaker fuel doesent cut it. I have screwed this second needle all the way in and it still idles rich. When i pinch the fluel line rpm goes up considerably. Middle rpm is ok, sounds nice, the motor screams. What else can i do? Move the spraybar closer in?
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Old Dec 18, 2012, 12:29 PM
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Istanbul, Turkey
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Hi Cesco if you can, try to make your LSN having more taper.Then it will block enough at idle position and will open spray bar totally when at WOT.
BTW,how you could determined your regulator needle stuck?
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Old Dec 18, 2012, 12:53 PM
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Hi turkthefirst,

I did succeed to move the spraybar inwards. I nearly destroyed my carb, but then i did realize i had to loosen the black screw on top first. Now the LSN will go deeper inside the spraybar. Hope that helps, cant try, if i start this motor at night family will kill me.

Needle is stuck when :
-bubbles in hose pump-carb and motor dies after 5 sec then stuck close.
-motor floods very quickly then stuck open.

Best way to free a flooded motor i found is to close needle totally, open carb to max, and then crank it a minute or two until it starts. I use a li-ion hand drill from aldi as starter ... works nicely.

I found this regulator is very sensible, or my gas is just very bad.
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Old Dec 18, 2012, 01:30 PM
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adding a return might be necessary now. I assume this addition should increase the pumping capacity of the pump. because now I see that the only problem remaining with my engine is that it can't supply enough fuel during nose up. I can open the LSN from 6 1/2 to 7 1/4 out and HSN from 2 to 2a/2 out, but there will be very tiny difference to notice. nose up will lean out at half throttle at 8500rpm, which is about 2000rpm higher then nose horizontally. Idle is nice and stable regardless of how much further I open up the needles. I will try to continue run in to see if this nose up issue improve or not. it seems to me that keep running in does push the rpm ceiling higher and better.
Earlwb, I will try to enlarge the pump fittings later on when everything else try out. I will be able to for the modification as per your explanation.
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Old Dec 18, 2012, 01:31 PM
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Turk, I'm not a Turkish, if that's what you were asking.
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Old Dec 18, 2012, 02:26 PM
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Quote:
Originally Posted by kentli22 View Post
open the LSN from 6 1/2 to 7 1/4 out and HSN from 2 to 2a/2 out
Sometimes i wonder what is different with mine. I have the LSN fully in, the HSN 1/2 to 3/4 out. HSN is very delicate, i have to change that single notch wise, while LSN doesent seem to have a big effect. I have the pump/regulator same height as carb, the tank is 15cm below.

Are u sure your regulator is not stuck close? I can assure you the pump has way more capacity than the motor will ever need.
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Old Dec 18, 2012, 02:51 PM
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I dont know if my regulator stock or not. all I can feel is that it gets better after each tank of ru in, but very slowly. but the top end seems to never have enough fuel. I can t never flood the engine, it's like there is enough fuel to run nicely, but never enough to flood it.
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Old Dec 18, 2012, 06:36 PM
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Hell I go away to work and lose touch on the internet and while my back is turned you guys write a book
I have three of these engines and they all run like clock work but not initially. I found the easiest way to bring them on line was to overhaul the pump/regulator as I have mentioned before as well as by others. With the new diaphragms and seals combined with better machined surfaces the fuel problem becomes a none issue and the motor runs smoothly and consistantly. I also put the larger fuel nipples on as well to improve the pulse line affect, ensuring the tubing I use is stiff walled so as not to lose any effect, important with such a small engine and small pulse.
With the overhaul completed the motor pumps the fuel up with three or four flicks of the prop, throttle fully open and finger over the carb throat. Takes a few hours of running before it will start easily without the starter and I always run it on 20:1 felt clunk and no bubbles.
Hope this helps
Glenn
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Old Dec 18, 2012, 08:24 PM
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USA, TX, Grapevine
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When i was flying my low wing plane today with the 9cc engine on it. I broke out my iPhone and used the RC Speedo App at the field. If I ignored the low readings and the high readings, the plane was doing about 88 to 96 mph on the low fly byes. The plane felt like it was going that fast too. At home when I tried to measure it off the video and computer speakers it was coming out much slower though. The engine sounded pretty good up in the air too.

I would agree with Brace in that some people may need to fixup the pump/regulator before it starts to work correctly. At that point the engines run really good and perform quite well.
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