a 61fx thing
 

Baxter,, my 61FX is ether on it's 7th or 8th gallon, it runs and starts great with a Slimline Pitts, and the Compression is very good,,, but there are 2 things I got to ask about,,

A) as I'm tuning the High Needle to find the Peak RPM (at full throttle) there is a good 1/3 of a turn where there is no change in RPM, this happens right at Peak RPM,,
another way to put this is as I'm leaning the High Needle (at full throttle) as soon as the Engine reaches it's Peak RPM I can turn the High Needle another 1/3 turn more before the RPM's drop from being to lean,, is this normal ??..

B) I'm finding from week to week, every Saturday I need to lean the Low Needle, I don't think the Low Needle is moving in flight,, could this just be because the Engine is getting more and more time on it, or is there something else that can cause this ??

if there is anything you need to ask me about this please do..

thanks !!
Jim

RE: a 61fx thing
 

A) It's normal. Most engines have a "flat spot" near peak.

B) Weather changes from day-to-day, week-to-week, so the needles will change their settings. Air temperature and humidity will both influence the mixture. Since they change from day-to-day, you'll need to adjust them. Usually, though, the idle mixture doesn't need much adjustment, but to keep it "dead on", you will need to do a touch up from time-to-time.

RE: a 61fx thing
 

"Low Needle"

yes I understand this about the weather, but I just keep having to turning the Low in so I asked, I mean there must be a point where the Low will never need to go leaner,,
but I will see what happens..

thank you !!
Jim