Hopefully someone has experienced this issue. My 1999 Mercury 250 EFI completely cuts off above 3,200 rpm. The engine wasn't taken out of the box until 2009 and has always been extremely reliable. Low hours considering the age. This issue started over a year ago. I have had two very reputable mechanics diagnose and repair the engine. Both have put a compression tester and show that a second before the engine cuts off the compression flutters then there is a major loss of compression. Compression is great at low rpm's. They have replaced the high pressure fuel pump, checked the low pressure fuel pump, replaced the diaphragm in the low pressure fuel pump, and replaced the battery cables. I am almost 2k into repairs and no solid diagnosis. Has anyone experienced this issue?
