Well Thank you all for your fruitful advices,

I have bought 2 O.S. #8 plugs. They are quite shorter in size, but so far they seem to be working fine, all I have a problem is the carburetor, my carb had loose nipple, I changed it, I borrowed another carb from senior flyer, screws got so tightened, it broke[:@] then I got metallic one, with the needle valve , the - minus and + plus plate was also moving causing my engine to stop, another wasteful sunday without flying but extremely hot day[]. Finally I got another carb of HB own manufactured, its not Perry, but it's HB's carb, but the lower part is smaller and little loose in engine, I have tightened it good, but I don't know how long its stay held on, we would find out in a week day when we goto flying. Im so far unable to fly my plane properly, its damn carb. If this carb doesnt work right, Im gonna throw this engine away.

Over here in Pakistan, I haven't seen hardly anyone using Nitro, here people use simple fuel 80% methanol 20% castor oil mixed this is what I have been using and never had any problem unless the carb is messy or other things are going on with engine.

I'd let you know about my flying if engine doesnt play up

Mody