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97 Challenger twin 787

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doubleaa

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I have spark for just a quick second then the spark is gone as I turn over the motor I do not have spark. Has anybody ran into the same issue? My dealer states its a bad MPEM which is no longer being made does anybody know of a place to purchase one?


Thanks in advance
 
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I have a 1997 Challenger twin 1800 starboard engine wouldn't run I put a timing light on each plug wire my PTO plug wire fires intermittent (other plugs wires fire consistent) . I took Mag plug, plug wires from port (running) engine swapped to starboard non-running) engine and inside gray box at the solenoids swapped red leads of both. my starboard fired up.

I am currently having my MPEM converted to PWC MPEMs I will let you know how it works out.
call Jess or Nick Carin at westside powersports.

Jess 813-363-9074
Nick 612-743-9311

There are others that do this swap too but Jess and Nick have been awesome folks to work with.

Frank
 
Hey Frank ,

Thanks for your help and keep me posted on how everything works out. Did not think it would be so impossible to get a MPEM for our boats.
 
I have it all figured out at this point and will be possibly be putting one together real soon.

This is a one year one model MPEM, it was a late addition to the line up, and thus they made VERY few 97 Challenger boats. In 98 they switched over to the big black panel. That makes it a VERY hard piece to find. Prob more than any MPEM in seadoo history.
 
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OK I need a new test subject. I am fairly confident Frank's MPEM was not bad, he has a bad rectifier. At least we have to send his ebox back and try it b/c I just refuse to chop wires off a potentially good MPEM.


So....I am 99% sure this is all going to work flawlessly aside from the two things I mentioned above. So who wants to be next?


I have two MPEMs ready to go and all the wiring mapped out. The plan is to use the OEM bullet connectors so future MPEM replacements are plug and play. As far as mounting them is concerned, the only way I see it working is taking the two studs out and putting one in the middle of the two, then stacking the mpems on top of each other using extra nuts and washers for spacers. Only issue with that is you will have to take the top MPEM out to check fuses. But then they are inside the gray box, and very solidly mounted might I add.
 
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I have seen people mount the whole electrical boxes from the skis in the boat. It comes out pretty nice like that also.
 
howie099 said:
I have seen people mount the whole electrical boxes from the skis in the boat. It comes out pretty nice like that also.
Click to expand...

Yes, but that would be a HECK of alot of cutting and splicing of wiring. This solution leaves it as OEM as possible, with the ability to just buy another jetski MPEM (it has 2) and install it in 10 minutes w/o changing anything.
 
I just wanted to bump this up; Doubleaa (alex) has the first swap in his hands and just waiting for feedback. I am very pleased with the way it all came out and am confident it will work flawless.
 
Im not going to post pictures b/c I earning a living off this stuff. What I will tell you is it uses two 97-99 SPX MPEMs.

On the 98s, its just much more work b/c you have to cut those 26 pin connectors off and splice in Jetski eboxes. I had a guy a few years ago do it on the SK 720s boat, and it took him about a week to decipher the wiring and what to splice. The problem with those panels is many wires run through the MPEM, using it solely as a junction point.

The biggest issue is the Neutral safety switch; if we could get that circuit mimicked into a little controller box we could splice in we would be set.
 
Most people skip the neutral safety hookup and use non-DESS MPEMS so you don't have to reprogram the keys, mount another DESS post, and cuts down on wiring. You can sometimes keep the old MPEM to run all the accessories if that part is not damaged or you just put in a standard marine fuse panel. I sure it sometimes easier to just rewire most of it yourself/
 
howie099 said:
Most people skip the neutral safety hookup and use non-DESS MPEMS so you don't have to reprogram the keys, mount another DESS post, and cuts down on wiring. You can sometimes keep the old MPEM to run all the accessories if that part is not damaged or you just put in a standard marine fuse panel. I sure it sometimes easier to just rewire most of it yourself/
Click to expand...

This is true of 720s, but 787s have digital CDIs. They never made a Non dess 787 mpem.

This thread is about 787s, but I did bring up 720s in my last post.

The neutral safety switch is a liability issue...it wouldnt be pretty if you have it shifted in forward at the dock, throttle wide open and you fire it up.
 
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ya that is true with the 787 with the DESS. 787 came out in 96 so you would have to do that, but I don't know how you can wire the neutral safety in without the OEM MPEM since that is built in that unit not the PWCs. I haven't seen anyone wire it in working. It is kind of hard to move the lever forward from neutral and have the levers forward. I can't move the lever that easy on my Sportster 1800 forward from reverse or neutral so I am guessing the challenger is pretty much the same with the levers.

I know I never had the levers forward more than an inch ever trying to start it.
 
I was going to say interrupt the dess post with the neutral switch, but that would cut the box, when you moved through the pattern, small circuit board could solve that issue..........
 
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