Does this attack plan makes sense for a 210 merc that just started running rough?

[Palm Bay Chuck]

I have a year 2000 Sea-Doo Challenger 1800 with a 210 hp Merc. It started running rough on my last trip out. It seems to be missing or "catching". It is hard to describe but basically the but will lose power and I cannot get above about 4000 RPM. The only way I could describe it is that I am missing fire in one of the plugs. So my plan was to do the following:

* Pull all 6 plugs replaced them with new making sure the gap is good.
* Inspect the wires that lead from each coil to each plug.
* Perhaps inspect the coil to make sure that the spark out of each one is hot. I'm not completely sure how to do this but was thinking about just grounding the coil to the engine block like I would do with a lawnmower!
* I just replaced the fuel water separating filter so I don't think that there are any impurities in the fuel. Although it's possible that that filter could be bad and could be restricting the flow of fuel, that is not really how the problem manifested itself though. He did not feel like fuel starvation but a cold spark.

I'm not an engine guy but I like to try to learn things on my own. Is this the right approach?

 

[henryb]

If you're only getting 4000 rpms, then you are probably missing on more then 1 cylinder. You might actually be not firing on 3 cylinders. Which might mean you have a bad switch box. There are 2 of these on your engine, each controlling 3 cylinders... one bank per switch box.

So here is a fairly easy (but none scientific) test. Start up your engine from being cold. Let it run for a minute or two. Turn it off and then by simply using your hand, feel the cylinder head around each spark plug. If you find that all 3 cylinders on one side is "warm" and all 3 cylinders on the other side are "cold".... then you probably have a dead switch box.

 

[Palm Bay Chuck]

Thank you Henry.

One additional fact is that the problem is intermittent. If I go WOT, it'll struggle to get 4,000 RPM, then it'll kick in and go over 5K, then lag back and so far. It works, then doesn't, works, then doesn't. Would this also be consistent with the switch box being an issue?

 

[Dr Honda]

HUmm......


from your description... you may have a bad CDI, and/or switch box.


On the 210... it's a true "Mag" ignition. AND... your system has 2 sets of charging coils. SO... at low RPM's... one set charges the CDI's... and at the higher RPM's... a second set charges the CDI's. The job of that switch over is "The switch Box"


So yes... it could be the switch box... but I would start with checking all the MAG coils with a meter.

 

[henryb]

Thank you Henry.

One additional fact is that the problem is intermittent. If I go WOT, it'll struggle to get 4,000 RPM, then it'll kick in and go over 5K, then lag back and so far. It works, then doesn't, works, then doesn't. Would this also be consistent with the switch box being an issue?

Yes, I was experiencing the same issue with my engine last year just before I had to replace one of my switch boxes! It was intermittent as well.

However, I would recommend that you take the Dr's advise and check anything that he suggests... He really is the expert!


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[Palm Bay Chuck]

Thank you fellows!

 

[Palm Bay Chuck]

Okay, I finally got around to changing the plugs and it made no difference. After running for 5 minutes or so, I noticed that the port side of the engine was hot (I could touch it, but externally it was maybe 140 degrees or so) and the starboard side was much cooler. 100 degrees or so. I suspect that the "Switch box" that controls the starboard cylinders isn't doing it's job. I'm looking online and in the schematics, and I'm not sure exactly which part the Switch Box is....

I'm assuming that it is item #20 in this diagram, which is called the "Switch Box" according to the parts list (duh....)

http://i.imgur.com/VQdlR5S.png

Am I right?

Now, can someone suggest a vendor that might have one? I'm checking SeaDooWarehouse and some others and having no luck.

Thanks again guys!

 

[henryb]

Yes, #20 is the switch box, there are 2 of them (same part)... They are mounted on top of one another, basically one on each side of that mount plate #19.
Well, there are a number of choices with that part:
- Mercury Marine still sells them,
- eBay has them used and new,
- places like boatparts.com probably have them,
- possibly Crowley marine?

Good idea to get your stator checked as I am having the same issue this year, but this time it's my Stator!


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