Cannot lean mixture without opening cowl flaps

[larrynimmo]

On 5/5/2020 at 1:13 PM, mooneyflyfast said:

Here's your answer. The no. 1 clyinder on our Js have a baffle in front of them that blocks a good part of the airflow.  Trim about 3/4 inch off it and your no. 1 will go from hottest cyl. to coolest.  My mechanic made a new one for me in about 10 minutes.  There is a thread on here from several years ago that covers this.  Good luck!

This is what my lean of peak reading look like and it’s pretty steady for lean of peak...I am going to measure mine and cut back 3/8” and I will report back

[ArtVandelay]

This is what my lean of peak reading look like and it’s pretty steady for lean of peak...I am going to measure mine and cut back 3/8” and I will report back

Don’t forget the non certified engine monitor CHT reading of #3 cylinder will read lower because it’s sensor is external, usually a spark plug ring, the factory sensor remains.

[larrynimmo]

On 5/5/2020 at 1:13 PM, mooneyflyfast said:

Here's your answer. The no. 1 clyinder on our Js have a baffle in front of them that blocks a good part of the airflow.  Trim about 3/4 inch off it and your no. 1 will go from hottest cyl. to coolest.  My mechanic made a new one for me in about 10 minutes.  There is a thread on here from several 

3 hours ago, ArtVandelay said:

Don’t forget the non certified engine monitor CHT reading of #3 cylinder will read lower because it’s sensor is external, usually a spark plug ring, the factory sensor remains.

Very good point...I didn’t go with the spark plug sensor, I went with the piggyback cht sensor that JPI recommended to me.  The spark plug sensors is the worst option as the reading is 40/50 degrees too high.

[larrynimmo]

I cut off 3/8” and saw a definite improvement of cylinder temperature for #1....I might cut off a little more and try it...still has hotter egt’s

it was a warmer day today as well, and it was bouncy so I had issues trying to get exactly the same rpm, manifold and fuel flow...