Guys, Id like some info on my carburetor. I've been tolerating some black sooty plugs in my O-360-A1A engine on my Starduster since I overhauled the engine a couple hundred hours ago. I was mixing auto and 100LL and assumed that taxiing with auto fuel was the culprit. A couple months back, I commented on this and another member said he had done similar and had no such conditions.
So, I've been adjusting the large knurled knob on the carb attempting to get to a point where, at shutdown, the tach needle jumps about 10-50 rpm and then falls to zero. 10 rpm is not visible on my tach, but 50 -- maybe.
Specifically, my question is: Does the mixture passage that is adjusted with the knurled knob affect the mixture mainly at idle or does it impact the mixture across the entire throttle range? And, I have always assumed that there is an enrichment built in for wide open throttle. True or false?
I've stopped using a mix of fuels and switched to straight 100LL for about 3 tanks of fuel now, and I still have mostly dry black soot on the plugs.
Comments please.
So, I've been adjusting the large knurled knob on the carb attempting to get to a point where, at shutdown, the tach needle jumps about 10-50 rpm and then falls to zero. 10 rpm is not visible on my tach, but 50 -- maybe.
Specifically, my question is: Does the mixture passage that is adjusted with the knurled knob affect the mixture mainly at idle or does it impact the mixture across the entire throttle range? And, I have always assumed that there is an enrichment built in for wide open throttle. True or false?
I've stopped using a mix of fuels and switched to straight 100LL for about 3 tanks of fuel now, and I still have mostly dry black soot on the plugs.
Comments please.
