87 Mercury- Spark problems

Trying to determine if the switch box is bad or if the problem may be the trigger coil or stator. There is no spark on lower cylinder and at times not on top cylinder. Have run ohm meter tests using Mercury repair manual as guide on stator, trigger coil, and ignition coils. All results were within the specified ranges except one stator test. The ohm meter reading across the two leads of stator was slightly lower than specified. The range is 3100-3700 ohms. The reading I got was 3070 ohms. Reversing the leads from one ignition coil to the other coil gave spark to the bottom cylinder and none to the top cylinder. Please anyone help me determine what part to replace.All these parts are costly so would like to get it right the first time.

Re: 87 Mercury- Spark problems

Sealegs,
Not a lot of info to go on but hopefully I make the correct assumptions.

Its a twin and you have no spark on the bottom cyl but you did switch the wires to the coils and the bottom coil WILL spark.

Then the stator AND both coils are good

Now switch the trigger wires where they connect to the switchbox to see if the spark switches cyl's, if the spark switches cyl's the box is good and the trigger is bad, if the spark remains on the same cyl the trigger is good and the switchbox is bad.

Re: 87 Mercury- Spark problems

go to maxrules.com clik technical assistance, there are test there.

Re: 87 Mercury- Spark problems

CharlieB-thanks for your prompt reply. Guess I was a bit skimpy in my description. However your assumptions were correct. I followed your directions switching trigger coil leads at the switch box. The spark did not move to the bottom cylinder so that makes the switch box bad. I will order anew switcbox tomorrow.
tashasdaddy-thanks for providing the nae of the web site. Looks like a lot of information on this site.