ORIGINAL: vti-chris
Thank you all for the info.
Of course we can,bring something to race!!!
The temps were very low(210F-220F).Lower than before(240F-250F)
So i don't thin there was any detonation.And the real problem was that the engine sounded rich all the time,with gurgles at higher rpms.
Getting the thread back on track...
So the engine is not picking up cleanly but the temps are about right...
Did you switch to the cooler plug? or are you still running the P3 V-Hot plug?
Even on a hot sunny day over here, I have been running the V-Hot plug and adjusting the mixture accordingly...
I am assuming as you have just switched fuel, you have fresh fuel... what percentage oil is the fuel? Indeed what fuel is it?
It may be best to reset the needles to stock and start from there... including the mid needle...
First get the car up to operating temp...
Run the car on a long straight flat out, and see if the engine cleans up.... if not, main needle in 1/8th turn, repeat....
Once this is done, set the car at idle, and see how long it idles for before loading up... You want it to idle for at least 10 seconds ideally, to simulate a crash and waiting for a marshall... You can also use the pinch test here... pinch the fuel line just before the carb and see how long it takes the engine to gain rpm/cut
If it cuts without changing RPM, likely it is too lean... if it gains rpm after about 1-2 seconds and then dies, it is about right... if it idles for much longer than 2 seconds then the revs gradually increase and then it dies its too rich...
Using these two benchmarks will give you a good bottom end setting...
Then slowly (1/16th at a time) turn the middle needle in so you just have the slightest hesitation when you open the throttle fully after idling... if you have to adjust this much more than 3/8ths of a turn, then something is wrong...
Now re-check the idle mixture setting...
That should be about right assuming you have good fuel, good plug and the engine is sound, shimming is correct and there are no airleaks in the fuel system... Any further adjustments should only be required to the main needle when something changes, but if you change the carb restrictor, everything will need resetting..
One more thing, the OS runs best with a restrictor in the carb, removal of it can make the engine harder to tune with some pipes... but I think you are running a 2050 arent you? so that should be fine...
Let me know how it goes...