Very hot number one cylinder EGT

[bvolcko38]

I'm using the number 2 needle with 90 octane non ethanol.

[mike.smith]

I'm using the number 2 needle with 90 octane non ethanol.

You might give the 2.5 a try.

[lutorm]

I found the fuel flow meter invaluable in making these adjustments. All the needle adjustments do is change the fuel flow, and with the fuel flow meter you can just see what it is. It takes a lot of the guesswork out. In principle you could start with a very rich needle, lean it until it runs like you want it, note the fuel flow, and then start looking for a needle that gives close to that fuel flow at full rich.

[WesRagle]

If you aren't able to tune the carb, just before you give up,

http://www.greatplainsas.com/posacarb.pdf

Best of Luck,

Wes

[Onex107]

So you are running the #2 needle. My question is, where is the mixture control when your #1 overheats? Do you have any "richer" left. If you don't. You need to richen the needle a 1/4 turn and run with the mixture out 1/4 to 1/2 inch to put you back to where you where. Then when your #1 is getting hot you can go richer with the mixture and cool it off. I went through all the needles and after a lot of research ended up with the #3 set up like I suggested above. I have a 1/2 inch of mixture to add when the #1 starts to overheat. It usually only takes about a 1/4 inch of movement to reverse the trend. Then when you have leveled off and set up a cruise rpm, lean the mixture back to put your egt's in the 11 - 1200 range. I cruise at 29 - 3000 rpm. If I push it above 3000 I am back into the hot cylinder problem. But, the #3 needle does not require any mixture change from wot to idle. It will run wide open on takeoff and 950 to taxi with the same mixture setting. I don't touch it again till I'm climbing out on the next flight. Just sayin.

[Onex107]

I don't know what my fuel flow is, and , I don't care. It's somewhere between 3 and 4 gals. per hour. The spark plugs tell the story. If they are sooty, you are obviously too rich and if they are clean you are anywhere from normal to too lean. The temps are the clue to too lean. I suspect, from 250 hours of flying with the Aerovee, that wot, 3000 plus, will put you in a leaner state than 2900. I think I find that reducing the rpm also changes the mixture to hot cylinders. Not sure, but it works. Has anyone calculated the area of the opening as it goes to maximum. Does it go over maximum?

[mike.smith]

I don't know what my fuel flow is, and , I don't care. It's somewhere between 3 and 4 gals. per hour. The spark plugs tell the story. If they are sooty, you are obviously too rich and if they are clean you are anywhere from normal to too lean. The temps are the clue to too lean. I suspect, from 250 hours of flying with the Aerovee, that wot, 3000 plus, will put you in a leaner state than 2900. I think I find that reducing the rpm also changes the mixture to hot cylinders. Not sure, but it works. Has anyone calculated the area of the opening as it goes to maximum. Does it go over maximum?

You should care! 3-4 gph is bordering on too low. 4.5 gph is a good average for where you should be. I ran on 3+ gph for too long and burned a valve, running too hot all the time. Fuel flow tells a LOT. During break in an AeroVee will run hot; any engine will, but it should not be routinely bumping up against 400 deg CHTs. After break in cylinders should never run hot unless you are in some extreme conditions.

Have a look here:
http://www.mykitlog.com/users/display_l ... 932&row=11