Captain reports about B737-300 autothrottles (a/T) having trouble holding adequate thrust for cruise...

Narrative:

This aircraft came from the hangar; after an engine change (#1 engine). During cruise flight about half way to ZZZ1; we noticed the autothrottles having trouble attaining adequate thrust for cruise mach. I disconnected the autothrottles and tried to manually set #1 engine throttle and found it would not move past mid position (80% N1 at cruise altitude). The throttle would come back; but still not go forward past mid. Called maintenance control and they thought it might be ice in cable. Power was controllable through an adequate range for normal operations; so we continued to ZZZ1 and landed without incident. Aircraft was taken out of service and repaired overnight in ZZZ1. Main engine control (mec) cable box was not correct for that engine. We flew it to ZZZ2 the next day and seems ok now. Callback conversation with reporter revealed the following information: reporter stated he did not have any problem with moving the throttle back; but could not go forward past mid position. But on the ground; after they arrived; maintenance started troubleshooting and noticed the same #1 engine throttle was also binding when moving the throttle aft to idle. Reporter stated he was told the main engine control box was not correct for the #1 engine that was replaced the night before.

Original NASA ASRS Text

Title: Captain reports about B737-300 autothrottles (A/T) having trouble holding adequate thrust for cruise mach. Disconnected the autothrottles and noticed the #1 engine throttle would not manually move past the mid position (80% N1 at cruise).

Narrative: This aircraft came from the hangar; after an engine change (#1 engine). During cruise flight about half way to ZZZ1; we noticed the autothrottles having trouble attaining adequate thrust for cruise Mach. I disconnected the autothrottles and tried to manually set #1 engine throttle and found it would not move past mid position (80% N1 at cruise altitude). The throttle would come back; but still not go forward past mid. Called Maintenance Control and they thought it might be ice in cable. Power was controllable through an adequate range for normal operations; so we continued to ZZZ1 and landed without incident. Aircraft was taken out of service and repaired overnight in ZZZ1. Main Engine Control (MEC) cable box was not correct for that engine. We flew it to ZZZ2 the next day and seems OK now. Callback conversation with Reporter revealed the following information: Reporter stated he did not have any problem with moving the throttle back; but could not go forward past mid position. But on the ground; after they arrived; Maintenance started troubleshooting and noticed the same #1 engine throttle was also binding when moving the throttle aft to idle. Reporter stated he was told the Main Engine Control box was not correct for the #1 engine that was replaced the night before.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	822408
Time
Date	200902
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Throttle/Power Level
Person 1
Function	Captain Pilot Not Flying
Experience	Flight Crew Last 90 Days 210 Flight Crew Total 23000 Flight Crew Type 13000
Events
Anomaly	Aircraft Equipment Problem Less Severe

Captain reports about B737-300 autothrottles (a/T) having trouble holding adequate thrust for cruise mach. Disconnected the autothrottles and noticed the #1 engine throttle would not manually move past the mid position (80% N1 at cruise).