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Mercury 150 Spark Problems

A

addicted2salt

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I have a 1996 mercury 150HP (offshore series) motor that has thrown me for a loop. When the trouble first started I ran about 10 miles until it bogged down and would not go any faster than idle speed. Next time I take it out. It runs great for about 20 miles until I let it sit for 2 hours then yet again it would not get on plane. I take it back home and check compression, spark, and fuel. All of which seem fine. On my last trip, it doesn't get on plane at all. Come to find out I completely lost spark in all 3 of the coils on the left side (cylinders 2,4, and 6).

I made sure the coils are grounded well and all connections are tight and still nothing. Someone mentioned a bad switch box? Any advice would be a HUGE help!

THANK YOU!!!!!
 
Swap the stator leads on switchboxes(blu & red) front to rear box and if problems follow to starboard side its a stator failing, if problems stays on port side its a switchbox.
 
If you switched those boxes, and the problem remained on that side, it's most likely the trigger coil (under the flywheel). You can test it with an ohm meter.

Jeff
 
i only switched the red and blue wires going to the boxes. I did not switch anything else. Which leads (wire color) do I use to check the resistance of the trigger?
 
Oooohh! Big difference. You discovered nothing by that approach, for all the stator (red and blue wires) does is generate electricity. You need to swap the switch boxes them selves to see if one of them is the problem.

Jeff
 
When the trouble first started I ran about 10 miles until it bogged down and would not go any faster than idle speed. Next time I take it out. It runs great for about 20 miles until I let it sit for 2 hours then yet again it would not get on plane.
Click to expand...
On my last trip, it doesn't get on plane at all. Come to find out I completely lost spark in all 3 of the coils on the left side (cylinders 2,4, and 6).
Click to expand...
Oooohh! Big difference. You discovered nothing by that approach, for all the stator (red and blue wires) does is generate electricity.
Click to expand...
If you knew how a ADI system actuality works it proved 2 things: (1) stator is not dropping the the low or high speed windings on either bank after it does a heat soak when motor was shut down. (2) stator is ok as problem didnt follow to starboard side . A trigger will not cause a complete bank to drop but a switchbox or a bad bias circuit in one will. Also check the resistor module(shift switch) as I have heard that if shorted it can do similar problem on salty motors.
 
fastjeff said:
Oooohh! Big difference. You discovered nothing by that approach, for all the stator (red and blue wires) does is generate electricity. You need to swap the switch boxes them selves to see if one of them is the problem.

Jeff
Click to expand...

I haven't found time to switch them yet, but If the problem does switch sides, how do I determine which switchbox is bad?
 
faztbullet said:
If you knew how a ADI system actuality works it proved 2 things: (1) stator is not dropping the the low or high speed windings on either bank after it does a heat soak when motor was shut down. (2) stator is ok as problem didnt follow to starboard side . A trigger will not cause a complete bank to drop but a switchbox or a bad bias circuit in one will. Also check the resistor module(shift switch) as I have heard that if shorted it can do similar problem on salty motors.
Click to expand...

You lost me with the high or low speed windings, and heat soak after the motor shuts down. (?????)

I know you can't say for sure without testing the components, but are you thinking its probably a bad switch box as well?
 
Go to Boatinfo.com and get the factory manual and test the shift switch and bia's circuit in switchbox. If the problem swaps sides when you change box it is likely box is bad but a bad bia's circuit can make a good box lookbad
 
..."You lost me with the high or low speed windings..."

That's those blue and red wires coming out of the stator. The blue plus ground is the low speed circuit; red plus ground the high speed (or is it visa-versa?)

Jeff
 
Oh okay! That makes sense.

I checked the DVA on the stator and it seemed to check out. So I swapped the switch boxes just to double check. After switching the boxes all 6 cylinders had spark.

What would cause that to happen other than a lose connection???? I thought a read a situation where this happens so am not convinced I fixed the problem.

Any ideas?
 
I thought they ran off a biased circuit?

Well if that is the case. What would cause that? What needs to be replaced? and will running it the way it is cause more problems?
 
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