Re: 1989 Mercury 4 cylinder switchbox question 2 wire red stator or 4 wire black stat
We believe the trigger is working properly, but with the Red two wire stator in place the engine fires and idles fine on the top two cylinders without any spark to the bottom two cylinders. With the stator swaped out to a Mercury black 4 wire stator (oe to the motor)the motor starts idles fine and I have spark to all four cylinders. With that setup at idle the dva tests to the four coils test within range and I have spark to the 4 cylinders using a spark gap tester. With the Red stator two wire setup I have using the dva tests 1 and 2s voltage test in range but on 3 and 4 I have no readings and using the spark gap tester no spark on 3 and 4. my gut tells me the switch box is bad. I wish there was an electrical test to check the switch box. If I were to replace it my concern is why did the box fail in the first place. Any tips would be appreciated. The motor fires but the boat when you give it throttle just falls on its face, no power and when we can get it on plane it wont rev pass 3500 full throttle. the plugs are consistently fouled up after a test run.
Maybe my experience so far will help.
This is how my '88 100 Merc behaved for years with the previous owner. He never fixed it because it would eventually pick up the other two cylinders. Eventually he lost all spark, gave up, got pissed, and sold me the entire boat and trailer for $300. I found a bad spark plug wire that probably stressed and killed the coil as well as the switch box. After replacing the switch box, plug wires, and one or two coils the motor ran better than most motors half it's age. I snickered at people with new-ish looking outboard motors struggling to get their pigs started at the ramp when my 23yo motor would kick off and purr before it made one full revolution on the starter.
But my story didn't end there... After a few rides, I lost all spark again. I was in the process of building my own DVA to start testing stuff when Hurricane Irene hit. I gave up and stored the boat until now. I was explaining my sequence of events to a Merc mechanic over the winter and he completed my story from the point replacing the switch box to now before I could. He told me a switch box that is going bad will over stress the stator and weaken it. He said after replacing just the switch box when customers refuse to pay for a new stator, trigger, rectifier as a package; he'll typically have the boat back in a few days because it just died underway with a bad stator. He assured me that the switch box does not typically get ruined under this sequence of events. I didn't even test anything with the DVA. I pulled my flywheel the other day and found a "red" replacement stator had already be installed once. It looks like a May, 1997 manufacture date stamped on the outer molding. So I have a "red" stator kit, trigger, and rectifier ordered. The mechanic said to just replace it all and be done with it so that is what I intend to do. We'll hopefully see what happens this weekend. The parts are expected to arrive Friday.
