by kbfan » Fri Sep 14, 2012 7:49 pm
I have a .48 that has previously run well. Broke it in per the manual, ran well, crashed plane, broke off carb, installed new carb, ran well again, crashed again - no engine damage (even closed throttle prior to impact, so no dirt inside, either). Cleaned the dirt out of the carb, took carb apart to make sure it was clean through and through. Now it starts immediately, idles well, but dies between 1/2 and 3/4 throttle. No lean out, doesn't sound too rich, just runs well, then dies - even if I gradually increase throttle, when it gets to about 3/4, it just suddenly dies. No bubbles in fuel line, either. Tank in proper position, clunks OK (brand new fuel system and plane), needle valve clear, less than 4" line from tank to carb. Have noticed a blackish oil leaking at muffler screw. Discharge from muffler looks normal. I'm really getting frustrated and hate to give up on an engine that I really like! Any suggestions?