@HELP Semi "emergency to me" :D Electrical experts in the house ?? 175 XR2 V6

[ToesintheSand]

Holiday weekend at Higgins Lake and I have minimal time to fix this issue. I have 2 dropped cylinders on 1998 Powerjet 175xr2, narrowed it down to coils and switchbox....I think. Spark tested all cylinders and found that two bottom cylinders on left bank are getting no/intermittent spark. One is dead and one gets an occassional spark. Top cylinder is a nice strong blue spark at 7/16 gap so I switched good coil leads from switch box with bad coils to make sure it was coil related. The bad coils did not work with good wires...so I'm figuring 2 bad coils. However, and this part I'm not sure about, I hooked the leads from one of the bad coils, to the good coil.....no spark to good coil. So, is it safe to assume this is the switch box and not the trigger. I say this because each coil on the 3 coiled trigger is supposed to be for 2 cylinders- one on left bank, one on right. Because both my bad cylinders are on the left, I'm deducing that it's possibly a bad switchbox and 2 bad coils. Does this make sense ?? Or maybe it's something eniterly different that I am missing?
This motor runs and moves along ok, but I know it's supposed to be close to 50mph so I started checking stuff and this is what I found. Had I known Iknown i was only running on 4 cylinders I would have never kept driving it.

 

[Bruce]

Seems like a good place to shout [USERGROUP=9]@HELP[/USERGROUP].

 

[Bruce]

Is the "switch box" a distributor? If so it sounds like it would be the problem.

 

[ToesintheSand]

Maybe, I wasn't sure if it was considered an emergency or not
I think it's a distributor of sorts for the system. I'm used to little 2 strokes and CDI boxes
[USERGROUP=9]@HELP[/USERGROUP]

 

[Bruce]

Can you post a picture of it? I am assuming that it will be an automotive distributor that is probably sourced from some GM engine. If so it is probably an inexpensive place to start troubleshooting.

 

[ToesintheSand]

It's not adistributor in the sense of "looks like one" It actually looks like a couple ginat CDi boxes. It's a Mercury marine part, best I can tell

 

[Bruce]

Well that is not an inexpensive fix. Do you have one of these switch boxes or two? Are the problems occurring in one or both?

 

[ToesintheSand]

Nope. 330.00 for a box and 50.00 per coil.

It has two. I don't know yet which box goes to which cylinders. Still looking in manual. I hoping it's one per bank of cylinders so I might need only one.

 

[ToesintheSand]

It appears that the boxes each own 3 cylinders . 1,3,5 or 2,4,6. Don't know the inner working so I don't know if failure of a switchbox means complete(all 3 cylinders) or if it can partially fail on 2 of three cylinders ..
it appears as though only one switch is onvolved since all the cylinders are in one bank

 

[Cobra Jet Steering LLC]

that is actually a v6 mercury outboard power head so I would imagine each box is the same, try changing the boxes to opposite sides and if the problem stays in the same place you may have an issue under the flywheel with a trigger , or a ground issue be sure the ground wire for that box is good and it is making a good connection, Sometimes the inner core corrodes and turns to powder making it difficult to detect, also could be a rectifier problem allowing ac current to get in the 12 volt system. The old mercury was known for that but this is a different engine. Electrical issues are not usually easy to fix

 

[Gym]

@ToesintheSand. as I mentioned to @Ronnie for his "no spark" problem on his jet ski, you may want to pick up an inline or inductive spark plug tester. http://www.autozone.com/autozone/ac...rk-tester/_/N-268s?itemIdentifier=900800_0_0_ That should help to confirm if you have high voltage coming from your switch box, which is really a solid state distributor. Sounds like you're on the right track though. Are you sure your switch boxes and wires are all dry and no high tension leaks on the spark plug wires?

 

[tdonoughue]

-> Disclaimer: I know nothing about this particular engine. But...

It would seem sensible to me that a fried coil would take out the switchbox (or vise-versa). If a coil overheats and melts or otherwise shorts, the resistance drops to nearly zero, which would not be good for the switchbox (basically you short it out). I bet you will need 2 coils and a switchbox... <owch>

 

[Gym]

-> Disclaimer: I know nothing about this particular engine. But...

It would seem sensible to me that a fried coil would take out the switchbox (or vise-versa). If a coil overheats and melts or otherwise shorts, the resistance drops to nearly zero, which would not be good for the switchbox (basically you short it out). I bet you will need 2 coils and a switchbox... <owch>

I would tend to agree with you @tdonoughue but only if the coil shorted to ground. However most coils just burn out and go open. It's not the switch box or battery that pushes current out but the load (coil, starter motor, light or radio) that draws the current. It only draws what it needs to operate but will draw too much if grounded at which point you either blow a fuse, damage equipment or burn wires.

 

[tdonoughue]

@Gym , I agree. Just saying that I can see it possible that the coil goes bad and shorts, which would explain the symptoms. If it blows and goes open, I don't see how the switchbox would get damaged (at least not the way I would design it...). I think.

 

[Gym]

@Gym , I agree. Just saying that I can see it possible that the coil goes bad and shorts, which would explain the symptoms. If it blows and goes open, I don't see how the switchbox would get damaged (at least not the way I would design it...). I think.

Yup, we're on the same page. Just like to see @ToesintheSand trouble shoot a little more and possibly save the cost of a new switch box although laura had to replace a switch box on her Sugar Sands.

 

[Cobra Jet Steering LLC]

This may be helpful, N A P A auto parts carries a lot of marine engine parts including electronics like the coils and pulse packs etc, years ago I did a lot of work on o m c engines and I always ordered my electronic ignition parts from them, they also have repair manuals for boats, Some of the stores don't even know they carry marine parts so with a little luck you can get the parts at a better price going through them. I checked on line and they still show marine parts.

 

[ToesintheSand]

Thanks for the input fellas! I will still try and test the leads coming out of box and trigger to verify, just don't know if I will have time. I may swap the switch boxes if I can get a second! I did switch around plug wires and check them with a an ohm meter and everything seems to be ok there. I cleaned terminals when I switched coil leads . I move stuff around while it runs to check for bad wires as well. I dislike parts replacement as a troubleshooting tool, BUT, I got lucky and found a guy on ebay that had the whole set of coils and a switchbox........shipped for 110.00by Thursday . Verbally guarantees they work....for whatever that's worth. Everyone else had to go to wharehouse with no guarantees on receiving parts by Thursday. Mercury only has five switchboxes left in their whole warehouse inventory.....gee, wonder if this was an issue From your replies, it seems I'm on the righ track.
If it fixes it for the weekend, I'm golden. Nothing worse than "Dad bought a boat!....but we can't go out on it" If it doesn't fix it, I have spares cheap AND he has a trigger if I need it. Anything but parts replacement in this timeframe and I'm afraid I'll never get it done. Got, got ,got,got,got no time........

 

[ToesintheSand]

Heh, just saw ur last post Cobra I will keep that in mind for future ref !