Question before replacing all ingnition components on my XR4

[mogfisher]

Hey folks. Heres the scoop. Upon reassembling my motor after a rebuild, I have no spark anywhere. Ran before but poorly (could have been a million reasons why) I've tested as follows.

150 volts at low speed wire on switch box from stator (should be 200-300)
15 volts on high speed wire on switch box from stator (should be 20-90)

No voltage out to coils.
All resistance checks on stator and trigger test OK.
black/yellow wire perfoming as it should
Advance module in trash bucket next to motor


I did clean the terminals on switch boxes with a wire brush, probably shorted some terminals together (off the motor) so maybe I discharged a cap into a terminal I should not have? I also overlooked the ground wire to the stator at first but did crank the motor with it disconnected.

The mechanic at the boat shop (who I trust) says its probably best to replace both switch boxes, stator, and trigger since sometimes if any one is bad it can kill the rest of the system. My stator is crusty looking anyway, and the ground wire had been pinched flat at one point (I cut and soldered that part out) so I dont mind replacing it for peace of mind. Just hoping someone might have some insight for me. Thanks!!

Adam
1988 Mercury 150 XR4

 

[mogfisher]

Re: Question before replacing all ingnition components on my XR4

Sooo. I retested with the switch boxes removed and plugs out for better cranking speed. I have well over 200v on low speed wire and 17v on high speed wire at the stator. I have less than half a volt (via dva) on all 6 trigger wires with the black lead of dva to ground. Seems like stator may be OK. Trigger bad? Replace trigger and switch boxes?

 

[mogfisher]

Re: Question before replacing all ingnition components on my XR4



Is this abnormal? Or just rusty? I ask because in my research I read that the flywheel hub has two stacked magnets and it looks like I only have one with space for another one. I cant imagine where it would be. I don't remember seeing anything fall off, but I took this motor apart almost two years ago so anything is possible.

 

[j_martin]

Re: Question before replacing all ingnition components on my XR4

Sooo. I retested with the switch boxes removed and plugs out for better cranking speed. I have well over 200v on low speed wire and 17v on high speed wire at the stator. I have less than half a volt (via dva) on all 6 trigger wires with the black lead of dva to ground. Seems like stator may be OK. Trigger bad? Replace trigger and switch boxes?

The trigger coils are wired to two opposite cylinders on the switch boxes. A diode in one grounds one end of it while the other is used to signal another cylinder. Testing from any one lead to ground with nothing connected is invalid. You can test between two opposing leads, for example cylinders 1 and 4 and get a valid reading.

I repeat, nothing in the trigger assembly is connected to ground, so readings to ground are relative, and only are valid if connected to the switchboxes.