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View Full Version : 1997 Merc Force 120 HP



steve4401
07-08-2009, 08:54 AM
"My engine has a miss at higher rpms. A mechanic checked the coils, spark, voltage, rebuilt the fuel pump(diaphram), carbs, cpmpression, all were OK. The #3 spark comes out clean, no brown on it, while the other 3 plugs having burn on them. The mechanic advises me the number 3 cylinder is getting flooded with fuel. Any ideas?"

galamb
07-08-2009, 10:11 PM
"The orignal sensor (trigger) on the prestolite ignitions has a nasty habit of developing a phantom "miss" on a single cylinder.

Of course it always works when you test it but if you hook a timing light to your number three plug wire and watch it under different operating conditions you may detect the miss.

If you do, replace the trigger (sensor), but go with a CDI/Rapier model - better than OEM and costs about half as much...."