Hey guys. as you know i recently picked up a FG sportsline mini.

now this is my first RC with a gas engine. the first 2 tanks were done on factory settings. and since then i have done 3 more tanks slightly varying the needle settings each time.

now after like a 4 day gap i tried to start it. but it comes to life and dies immediately. stays alive for maximum of 1-2 seconds. in two of the start attempts it has even backfired right as the engine dies down.

i tried setting everything back to the stock needle settings, but this has not changed anything. still does the same.

any help on this would be greatly appreciated.

thx
ajit

First thing is to check the spark plug condition. Trouble shoot one component at a time.

checked the spark plug. a lot of dark sooty residue on the tip. i tried cleaning it and trying it again. after a few attempts of trying to start it, the tip is again coated with soot.

the fuel mixture is the manual recommended ratio. i mixed it myself.

and one more thing ajo sir. the third screw on the carb. the idling screw. are any adjustments required for that?? havent touched it till now. nothing about it in the manual or anywhere online.

thx,
Ajit

Hmmm... Really not sure, but do work out with fuel- I think the combustion is really dirty or 'choked'
Dense soot on plugs is not a good sign..
I am trying to find out a solution from others.. Don't worry, it'll get fine!

Dear Ajit, black residue on spark plug indicates improper ignition.This improper ignition can be due to two reasons:
1:Very rich mixture (with excess fuel)
2:Sometime due to improper timing of spark.

While a proper ignition changes the color of spark plug to milky white..

So if you have touched the timing came, readjust it as per instructions..
Try running the engine as lean as possible in beginning, and proceed by enriching the mixture..

@abhay1290 - thank you for that. but the manual has no instructions on the timing adjustments. any advice on that will be appreciated.

k. when you mentioned the first point about the rich mixture i got a doubt. the last batch of fuel i put in was not mixed by me. i was kinda busy with work and asked my driver to get some fuel and mix it with 2T. asked him now and he says he got the 2T mixed at the pump itself by the pump attendant. so there is a chance it might not have been mixed in the right proportion.

am emptying the fuel now. will mix again. on a side note, will this cause any long term damage?? the fuel was not used for running it as i could not get the car to start.

thx

Any thing more than 40ml oil to a litre can cause fouling of the plugs. Lower mixture can cause damage. Also idling the engine too long can foul plugs as per some articles.

The idle screw is for stable idle. If the engine does not idle, turn it in and the idle should increase. Did you check the spark on the plug? Put the plug on the wire and bring it closer to a metal object. There has to be a strong blue spark. If not, clean and try or replace plug.

Quote from: abhay1290 on June 29, 2011, 12:31:40 PM
So if you have touched the timing came, readjust it as per instructions..

Are you referring to a timing cam??? There are no cams on this engine as far as I know. 2 strokes usually have reed valves. Timing will have to be adjusted on the sparkplug. But There are other ways to advance or retard timing. I am not sure.

There must be a small flywheel with a magnet on one side (since I take it its not electronic ignition) Usually timing is set through a slot in the inner part of the hub of the flywheel and a key that aligns this slot with another slot on the crankshaft. Sometimes the key can be loose and the hub flywheel might shift, changing the timing. However, I dont think this is a likely scenario -since it was running fine just four days ago.
My suggestion would be to check plumbing on your fuel lines, and then the carburator for any dirt blocking the tiny fuel passages or the fine wire screen inside. (You will have to take carb apart - I assume its a walbro -so refer to drawings and instructions for diassembly/assembly online. Here is one link     
http://www.rcaer.com/userfiles/file/RC%20Aero%20-%20Tuning%20a%20Walbro%20Carb%20the%20Right%20Way.pdf