rc_lover

Ive had some great use out of the FGBaja so far, but near the end of the last run it started to lose power and wouldnt start after this. There is fuel in the bulb, compression and have cleaned the filter. The only thing left is the spark plug. it was greyish and black which was cleaned after, and when secured in the harness and connected to the engine casing, produced no spark. so I assume the spark plug has gone which is why it won't start.

So, could this be anything to do with the oil mixture?as stupid as it might sound, the oil mixture bottle had measurement increments which produced different a different volume quantity of oil than the actual measuring jug. slightly more oil was therefore used. could it be anything to do with this? could it also be due to the way it was run?It hasn't been on full throttle that much either.

any other reasons for a dud spark plug?

Thanks.

dimag093

A mixture more than 4% oil to gas ratio combined with a rich carb setting may foul the plug pretty easy[8D]

rc_lover

Thanks for the reply. The settings are set by the factory default but Ithink it's the oil mixture thing. it was also instructed to use 150 ml of oil to 5000 ml of fuel. this works out at 3 %which isn't quite 4 %. the recommendation would be to put even more oil than was put in before (e.g. 200 ml of oil to 5000 ml of fuel). why would it oil up if it's < 200 ml of oil to 5000 ml fuel?Unless there is something Ive missed here. Anyway am gonna drain the fuel from the car and start again with it.

2 deep

Hi, i think you should change you spark plug first!!!

rc_lover

Hello. Yeah that's the plan.

rc_lover

Also just to say on the oil bottle it says to mix 150 ml to 5 litres which is a 3 % mix. Not sure why it isn't 4 % though.

dimag093

What kind of oil you've got ?
Zenoah engines need oils with sufficient lubricity beyond 14k RPM otherwise they can size in a blink of an eye
A 4% oil to gas ratio is absolutely necessary in order to stay on the safe side not to mention the oil has to be a PREMIX kind
A 3% mix is maybe enough for a non RC engine and/or an engine revving lower than 8k RPM (my Vespa runs on a 2% mix but barely reaches 4k flatout)

rc_lover

Interesting. It is "King Cobra Complex Competition" model car racing oil. Not sure why it says a 3 % mix then. more over, am not sure why it oiled up at less than  4 %. another reason could be that the fuel was not mixed around prior to being put in the car. I think youre supposed to mix it around a little bit if it's been stationary prior to putting fuel in the car.

dimag093

Given the fact that King Cobra Racing has been dealing with large scale RC , I'm not disputing the recommendation of 3% ratio
I suppose it has been tested on various engines and conditions in order to be true.
However I would prefer to start with the basics , a 4% that is , see how it goes and then decide whether to be risky or not
After all is less painful to trash a spark plug than a complete cylinder

rc_lover

Yeah I know what you mean. The spark plug was replaced and it started! A 150 ml mix of oil was used which is what it recommends anyway.

rc_lover

nm