Mercury 150hp V6- No spark on one side

[shaneburris74]

I am not getting spark on half of my cylinders.
a. When I originally discoverd the problem I switched the power packs. The problem moved w/ the power packs so I thought great I know what it is. I bought a USED power pack locally.

b. Installed used power pack. Same problem still exists..no spark on one side..will move with power pack. I assume used power pack is bad. Shop has another one. I take it home....same indications..now I'm really scratching my head. Only one thing to do now.

c. I buy a NEW power pack. Guess what...same problem. Whatever side the NEW power pack is on is where I don't get spark.

d. I have removed the black/yellow kill wires..it still starts with them removed.

e. I spoke to a tech at CDI electronics...they say I should buy an additional power pack and that they always recommend replacing both (convenient for someone who sells power packs). My local mechanics says he's heard it recommended but never required.

d. I removed my known good power pack and only left the new one on to just test it by itself to try to prove/disprove CDI's theory. It gets no spark with only the new power pack installed.

e. Most people I have talked to have told me to start trouble shooting the stator, but haven't I proved both sides of the electical system good by switching my power packs and being able to get spark on either side depending on where the non-new pack is?

I think this is a doozy of a problem because it just doesn't make sense. I am in the Navy and work with electronic weapons systems and everything that I've learned says if you switch a component and the problem moves then that is a faulty component.....that doesn't seem to ring true here.
Please help! My boat is not near as much fun when its sitting in my driveway...Thanks, Shane Burris

 

[Laddies]

Re: Mercury 150hp V6- No spark on one side

Have you removed the bias wire between the switch boxes or the yellow wires from the rectifier, both can cause a problem like you have.

 

[j_martin]

Re: Mercury 150hp V6- No spark on one side

Like laddies said, a lot of the time, the bad switch box (murkurese for power pack) is the one that fires, killing the other one through the bias circuit.

If you remove the bias jumper,and both work, that's your problem. Don't run it that way, replace both switchboxes. They can sometimes wreck each other through the bias circuit. The ones you remove can probably be used on 3 cylinder engines.

Unless the stator is totally smoked, anything you do with the yellow wires shouldn't bother the ignition.

hope it helps
John

 

[shaneburris74]

Re: Mercury 150hp V6- No spark on one side

I have removed the black/yellow wires and it does'nt change anything. I will try to remove the wires from the rectifier though. Are resistance checks on the stator sufficient to tell if its bad?

 

[Laddies]

Re: Mercury 150hp V6- No spark on one side

Sometimes! The bias wire really needs to be disconnected

 

[shaneburris74]

Re: Mercury 150hp V6- No spark on one side

Alright...I got it fixed. The quick down and dirty is that the wires coming from the Port and Stbd power packs were swithed. So the port pack was sending fire to the stbd side and vice versa. So I had a bad pack in the system this whole time but kept thinking the opposite side was not firing.
I took the new pack and the one that I thought was bad and put them on. It fired up and had spark on all cylinders...with one exception. The presumed bad pack has a lead broke off of it that I broke of while removing it. That lead would not send spark to the lower cylinder on whichever side it is on. When I was checking spark I noticed that the missing spark was not where I thought it would be...so I start tracing wiring and low and behold the wires are crossed.
That gives a very simple explanation to a seemingly crazy problem.....I'm kinda kicking myself for making the assumption it was wired the way it should be but oh well...its fixed now and I'll be in the water tomorrow!
One more question though..the black/white lead and red lead that come off my stbd pack that are spliced should go to an "advance module" according to my shop manual. This is not there and has never been there when I've ran it prior. I know it seems to run fine without it but is this something I should look into putting back on?
Thanks for all your help and patience and to all reading this...when the problem gets really hairy and don't seem to make sense CHECK TO MAKE SURE THE WIRING IT GOING WHERE YOU THINK IT IS!

 

[Laddies]

Re: Mercury 150hp V6- No spark on one side

Most idle stabilizer are long since removed, the were very trouble some