Very odd tuning issue....(FIXED, LOSE COOLING HEAD)

[ninnon]

Usually I don't have to consult the forums or the internet for tuning issues, but this one has really stumped me. The past few weeks, I have been using my car pretty much everyday on tarmac, and strangely for winter it had been running the best I've ever seen it, but today I went to start it and it all went wrong, as with everything I attempt. Anyway my dilemma is: From the transition between summer and winter with a temperature difference of about 15 degrees I kept re-tuning and it has pulled through, yet from one day to the next with a temperature drop of about 1 degree I just can't get the engine to tune whatsoever, every tuning adjustment I make either takes ages to take affect or does nothing at all, one minute it will run ok, so i'll turn it off, 30 seconds later I turn it on and full throttle sounds like a broken chainsaw at maybe only 10,000 rpm. Sometimes the idle is too high, 5 seconds later it won't start at all. I have tried setting to base settings- it runs appallingly so I try to tune, still runs appallingly. The difference between the high end being flush and being screwed in quite far is extremely minute, and worried to tighten any further. As I said, this one really has confused me.

 

[BamaFan]

Sounds like your sucking air from either the needles, the carb neck, fuel line, fuel tank or breather. It could possibly be the engine has lost compression but that would be my last conclusion. From the way it sounds I think you have a air leak.

 

[ninnon]

Sounds like your sucking air from either the needles, the carb neck, fuel line, fuel tank or breather. It could possibly be the engine has lost compression but that would be my last conclusion. From the way it sounds I think you have a air leak.

Thanks for your help but I have fixed the problem, you hit the nail on the head, the cooling head had came lose!

Thanks for your help but I fixed the issue, the cooling head had come lose and oil was leaking out.