float level and carb vent.


--
James H. Macklin
ATP,CFI,A&P

"Dave" wrote in message
...
| Hi All!
|
| OK, since the collective talent in this group greatly
exceeds
| mine and those around me...
|
| Today the engine in our 151 (O 320-150hp)Warrior stumbled
| during power reduction, and we were able to repeat the
symptom.....
|
| Here are details
|
| OAT -5 C, 2350 rpm, kinda rough air, pulled back
throttle to
| decend after passing traffic..
|
| I think we hit a bump which caused the throttle to be
| retarded quicker than normal, engine stumbles for 1
second and
| resumed operation at the new (lower ) throttle setting.
|
| We were able to repeat this several times, carb heat
on/off,
| fuel pump on/off, leaned rich of peak/ full rich, left
tank/right
| tank, rt mag/left mag/both. - as long as we waited a
couple of minutes
| to try again. No evidence of carb icing, dew point was
+10C
|
| Moving the throttle immediately back to cruise, then
sudden
| retard, no problem. The stumble could be repeated by
waiting 2 -3
| minutes .
|
| Recent maintenance, oil & filter change 1.5 hrs ago.
|
| The stumble was like the mixture was momentairly too
lean,
| similar to the lean test during runup...
|
| At 3500 ft, lean setting was at 60% of mix lever travel to
| full rich..
|
| Any thoughts from you engine talents out there?
|
| Cheers!
|
| Dave