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My mechanic has almost run out of suggestions to solve this problem so I will appreciate any help you can provide. Some background: I have a 1946 415C which was converted from 75 HP to 85 HP by a previous owner by making 2 changes in the carb and by changing the full point to 4.5 quarts on the dip stick. The 337 form lists no other work. During it's last annual (Sept 2006) all cylinders were in the mid 70's, 8 new plugs were installed, and a new wiring harnsess was installed. About 3 months( 25 hours) ago I experienced an RPM drop on the right mag that I could not correct. After much checking by my mechanic, I purchased (from Aircraft Spruce) an overhauled Bendix mag. After installation and timing the problem was completely eliminated and left and right mag drops were about or even less than 50 RPM. I flew the Ercoupe about 20 times for a total of 25 hours with absolutely no mag drop problems. Then, about a week ago, at run up I had a 200 RPM drop on the right mag. My mechanic removed, cleaned, and tested all 8 plugs. All tests indicated they were firing correctly and after removed the plugs were dry and appeared to have been firing. The new wiring harness also checked out properly. So, I bought another overhauled right mag, had it installed and the engine timed, and the 200 RPM drop continues on the right mag. Today, after checking to make sure the left and right mags are identical, we plan to switch the mags and see if the problem moves from the right to the left side. If the problem moves to the left side, we believe that the the overhauled mag I just bought is defective (just like the one with 25 hours on it) I would appreciate any help and advice from anyone. Thanks Dennis Hatfield -- Dennis ============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm
