2000 sportster 1800 no spark

[altf4]

just took my parents boat out of storage and one engine wont start.
first thing to take into account is im not a mechanic.
the engine cranks and has fuel but has no spark.
things ive done:
changed plugs-nothing different
switched the black box that the plug wires are coming from on the non-running engine to the running engine and it ran fine but the broken one still didnt go.
none of the three 20 amp fuses are blown by main power cut-off(none of the smaller ones which i assume are accessory fuses are blown either)
the main strange thing im finding is when the one engine is running and i try to start the other it cuts the running engine out.
any other small things i could check or is it time to go get bent over at a shop?

 

[LouDoo]

I'm going to move this to the 2-stroke sport boat forum, I know that you're supposed to get special attention in the Premium Member section, but too often you don't. I think you'll get more attention in the regular section, if you want this moved back, just let me know.

Lou

 

[Waterluvr]

So you have the Mercury V-6 M2 engines in that boat, carbureted and not fuel injected correct? Let's start with your engine serial number to reference the right manual and electrical specs.

 

[altf4]

No they are the twin rotax engines.

 

[Waterluvr]

No they are the twin rotax engines.

Sorry, when I looked that up last night it showed M2 power for the 2000 Sportster. So, I have the 99 manual and the 2001 manual but no 2000. Does that have a single MPEM module or two of them? Need to figure out why that bank of coils isn't firing.

 

[altf4]

Sorry im not that savy with these kinds of things. But both coil modules are connected.to the same black box that also contains two banks of fuses? Does this help or where should I look?

 

[Waterluvr]

Sorry im not that savy with these kinds of things. But both coil modules are connected.to the same black box that also contains two banks of fuses? Does this help or where should I look?

That does help, I got your DM and replied. There are other members here that can actually test that MPEM module that controls those functions, I do not have the equipment to do that unfortunately.

I would place high value on input from member @ Sportster-2001-951C-Stock as he has a better working background with these twin engine single module boats than I do. Not sure if he can test that for you but he can probably get you with someone that can.

 

[Sportster-2001-951C-Stock]

Yeah, unfortunately I don't have the electrical schematic for the dual engine single MPEM setup and didn't realize they still used the single MPEM configuration in 2000 but I can tell you if your MPEM is toast they are very hard to find replacements for. If yours is single MPEM and you plan on keeping the boat for eternity, try to find a spare MPEM for it, along with the lanyard key already programmed.

So both engines crank but only one will start and run, and while attempting to start the 2nd engine the first one dies for some reason. This might be important, and it's rather strange. Almost sounds like a weak battery may be causing these problems, how old are they?

Does your boat have the dual cranking battery configuration, or is it single battery?

Assuming the battery is in good condition, I think I would check out all the battery cables and such. Low voltage can cause lack of ignition, this happens if voltage drops under 10 volts during cranking, no spark is the result, it's quite common on skis that run small(weaker) batteries.

You said "the main strange thing im finding is when the one engine is running and i try to start the other it cuts the running engine out. "

This makes me think you have the single battery system and your battery is weak, probably needs to be replaced but you can try to charge it but only if you disconnect it first, to avoid damaging your MPEM. You might be better off locating a known good battery that has plenty of capacity, like 800CCA(cold cranking amps) or more always works nicely.

So check that stuff out, and remember NEVER charge or jump start the battery with any charger while the boat is connected to the battery, this can damage the MPEM instantly if the system voltage rises much more than 14.4 volts.