Long e-z pilot reported returning to the departure airport after the engine sputtered and would only...

Narrative:

During run-up; departure; and initial climb the aircraft operated normally. During the departure climb the engine had a single miss and then a few seconds later the engine sputtered and could only develop idle power. I cycled the throttle numerous times; checked fuel pump was on; mixture rich; and added carb-heat. I immediately turned the aircraft left to begin a 180 degree turn to return to the airfield. I notified the tower that I was returning to the airfield. There was a gusting tailwind on landing with only 1400 ft remaining and the long-ez calls for 1800 ft minimum. I landed the plane with the nose gear raised to reduce the landing roll. After landing; the aircraft was restarted and when the throttle was advanced beyond 1/3 throttle the engine would stumble; generate black smoke; and drop to a very rough idle. The exhaust pipes were black with soot. The mixture control was ineffective. The throttle body injector was inspected and a small amount of corrosion was found inside the inlet fitting. The fuel tanks and gascolator sump drains were drained and there was no indication of water. The throttle body had about 100 hours and 3 years since install. The throttle body has not been run to determine if this was the root cause of the failure. In talks with the manufacturer; it is possible that an internal failure occurred that caused excessively rich mixture above 1/3 throttle.

Original NASA ASRS Text

Title: Long E-Z pilot reported returning to the departure airport after the engine sputtered and would only develop idle power. Ground inspection revealed a possible problem with the throttle body injector.

Narrative: During run-up; departure; and initial climb the aircraft operated normally. During the departure climb the engine had a single miss and then a few seconds later the engine sputtered and could only develop idle power. I cycled the throttle numerous times; checked fuel pump was on; mixture rich; and added carb-heat. I immediately turned the aircraft left to begin a 180 degree turn to return to the airfield. I notified the tower that I was returning to the airfield. There was a gusting tailwind on landing with only 1400 ft remaining and the Long-EZ calls for 1800 ft minimum. I landed the plane with the nose gear raised to reduce the landing roll. After landing; the aircraft was restarted and when the throttle was advanced beyond 1/3 throttle the engine would stumble; generate black smoke; and drop to a very rough idle. The exhaust pipes were black with soot. The mixture control was ineffective. The throttle body injector was inspected and a small amount of corrosion was found inside the inlet fitting. The fuel tanks and gascolator sump drains were drained and there was no indication of water. The throttle body had about 100 hours and 3 years since install. The throttle body has not been run to determine if this was the root cause of the failure. In talks with the manufacturer; it is possible that an internal failure occurred that caused excessively rich mixture above 1/3 throttle.

Data retrieved from NASA's ASRS site 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	1400165
Time
Date	201611
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	Amateur/Home Built/Experimental
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Route In Use	Direct
Flight Plan	None
Component
Aircraft Component	Engine
Person 1
Function	Single Pilot
Qualification	Flight Crew Private
Experience	Flight Crew Last 90 Days 30 Flight Crew Total 989 Flight Crew Type 500
Events
Anomaly	Aircraft Equipment Problem Critical

Long e-z pilot reported returning to the departure airport after the engine sputtered and would only develop idle power. Ground inspection revealed a possible problem with the throttle body injector.