hi ..
i have a os 46....it was  last flown a year back...i dnt know much abt the engine( never started by myself)....now iam in a place whr i have noone to help me.......had sm problem with carb...thanks to anwar aand others ....
now when iam trying to start the engine it is not starting up...procedure followed by me( as i saw people doing also in some videos)
1st i primed the engine by opening throttle to max and closing the lid of carb .
2nd closing the trottle and then rotating the prop.
3rd with booster plugged and throttle half open rorating the prop...

even after doing it the engine is not getting started ...is it due to the fuel mixture( castor oil is between 25 to 35%)
or wrong technique ..plz help me..

During the priming, you have to see if the fuel is being sucked into the carb. You should see the fuel reach the carb inlet.

Also, check your glow plug to see if it getting heated up properly, double check your needle settings.

Are you using a starter ? Does the engine fire at all ?

yes the fuel is sucked in the carb..
glow plug is brand new frm rcdhamaka....
no iam not using starter....i think engine is firing ( from the sound) but not sufficient to start...
my fuel mixture is more than 6mnths old...is this the prob...

This thread has quite a bit of relevant info on this :

http://www.rcindia.org/fuel-and-engines/tip-dealing-with-a-glow-or-nitro-engine-that-refuses-to-start/

My exposure to home-brew fuel is limited, so I request others to pitch in.  Old fuel is not a good thing, but I am not sure if "6 months" is old enough ! 

Do verify needle settings, and check for any leaks in the tubing.

hi, if u have fuel mixed with castor oil lying for 6 months, its not a problem. OS 46 is one of best engines for starting and running. Start from the beggining, open main needle 1.5 to 2 turns if ur engine is run in. close carb till the openeing is just closed, and hold it here, now screw in the idle needle till it comes to the stop, and now open it 1.5 to 2 turns, Suck in fuel and start, should give u start within 2 flick, provided fuel got sucked in, so remove the cowl to be able to see the fuel line to the carb.
Ramesh Tahlan

hey it started 4 1 time...i think i  lack the skill.....evertime i land up with a overflowed cylender..plz guide me with the technique...

wat exactly is the main needle..the one which is inside the carb..

Ok, the main needle is the one which sticks out of the carb on the opposite side of the throttle link to servo, and now in the latest carbs, it is inclined backwark 30 degress, and in some mounted remotely behind the engine. close it fully, with ur fingers, and then open it 1.5 to 2 turns. The idle needle is inside the carburater barrel, and u would normally need a dash screwdriver with about 3 mm width, and gently put the screwdriver inside the barrel and set it as i have described in my rarlier post. block the carb intake with ur thumb  and rotate the prop 3 to 4 times with ur hand, u should see the fuel being pulled towards the carb through the fuel line. Make sure ur glow booster is charged, and flick sharply. it should fire in 2 to 3 flicks. but remember, a perfectly tuned engine, with the throttle at perfect idle, will not start easily, so u must move the throttle stick a few clicks up or if ur Tx does not have ratchet on the throttle, look and the barrel and open it about 1/4. now start. Do check that u have not burnt out the glow plug, by removing it and connect to glow booster. Safest glow plugs to use are OS #8, u wont go wrong. Till today, i have never used a starter on a glow engine, be it 2 or 4 stroke.
Happy starting
Ramesh Tahlan