I have a Mercury 150, carburetor engine somewhere between 1987 and 1996. I have no spark on cylinders 2, 4, 6, at idle. However, when I rev-up the engine, the engine smooths out and I get spark on cylinders 2, 4, 6. I checked voltage going to coils for 2, 4, 6 and there is almost no voltage at coil UNTIL I rev engine, then voltage increases and I get spark. PLEASE help me find a solution to my problem so I can get back out on the water. Thanks and God bless!!

That is sign of failed low speed stator winding. You need to order the replacement by the engine serial number due to different stator/rectifier designs.

thanks so much for the reply. that was one of our concerns too, but why would it affect only one side and not cylinders 1, 3, 5? they are firing normally.

also, how much does it cost in parts for what i believe is an older model than 1996, probably closer to 1987. thanks again and God bless!!