I have an 84 or 85 Merc 150 Black Max ser# 6409624. I developed a water jacket leak on thestarboard bank...engine started skipping erraticly. Got home pulled cowls and coils were wet. Dried coils out, replaced water jacket gaskettook it out the next day...idle was a little rough but ran fine from 1200 to wot(5200).I fished all day, came home was running motor to flush out salt water...maybe 5 mins at idle then started skipping really bad. Checked plug wires with test light, the two top coils on starboard bank were not firing. My question is, could both coils have gone out at the same time or am I looking at a new stator? And if so how hard it stator to replace?
hello usually a staor failure will take out an entire bank. the triggers fire in pairs but I think on opposite banks. I would carfully test the coils. if the got wet inside they will arc internally. try swapping them with a known good bank and see if the problem moves with the coil. good luck and keep posting
Switch the stator leads that go to each switch box. At the top of each box there are two wires you need to switch from one box to the other. One has a Red and a Blue, the other has a red/white and a blue/white. Switch them from one box to another. And retest for spark. If the no spark condition moves to the other bank, you have a bad stator... If it stays the same you either have a bad switchbox or coil(s) problem.rodbolt is correct though, only two cylinders not firing most likely is not a stator... But it's an easy test. Let us know what you find, and we can go from there....
Originally posted by KCLOST: Manatee,Did you find out anything????
I finally got the chance to mess with it today. I switched places with coils...same cyls still not firing...switched wires on switch boxes...no change...called a local repair shop that happened to have a used switch box for 50 bucks. Bought it put it on and now only one coil isnt firing (#1 cyl) top coil same side. So I changed places with the swich boxes...#1 cyl coil still not firing.All others are firing strong. Even switched places with plug wires. Any suggestions?
Okay, I have done some more checking. I disconnected the white jumper wire between the two switch boxes and checked resistance on each box by going from jumper wire post to engine ground. Starboard box(cyls 1,3,5) reads 14.88 ohms(original box)This was originally connected to the port bank and worked fine there. Port box(cyls 2,4,6)reads 14.05 ohms(used box from repair shop)Tried this box on starboard bank first and still no fire to #1 cyl....left jumper wire disconnected and started engine. Still no fire to #1 cyl(coil has already been ruled out as culprit)Could difference in bias resistance be causing the problem or could it be the trigger? We also ruled out the stator by switching wires on boxes.The only other thing I know to do is pull flywheel and take a look for obvious signs of damage.
Did you completely switched the boxes (removal of all wires from one box to another) also...?If so, and no change, it sounds like a trigger problem, since you confirmed it's not the stator by just switching those leads from one box to another...
Originally posted by KCLOST: Did you completely switched the boxes (removal of all wires from one box to another) also...?If so, and no change, it sounds like a trigger problem, since you confirmed it's not the stator by just switching those leads from one box to another...
Yep, I switched all wires on both boxes still no change. Ill check resistance on trigger wires and get back to you. Thanks
Mercury 150 coils/stator?
starboard bank...engine started skipping erraticly. Got home pulled cowls and coils were wet. Dried coils out, replaced water jacket gasket
Linear Mode
