Hello, Im new to this forum but I will try and do the best I can to describe my problem. I have a 1996 Seadoo 720GS that has just recently gotten back from getting everything fixed at a local mechanic shop. The guy who was doing the work has had a shop for the past 20 years and had good reviews from friends and other customers and got my ski running well. I picked it up from the shop running, took it home, parked it overnight until around 12 noon the next day when suddenly from outside I hear my ski starting by itself without the DESS key and idling all on its own. I decided to unbolt the negative wire off the battery until I had time address the problem. I tried figuring out the problem but every time I connect the negative wire the motor would turn over regardless if it had the key on it or not. My mechanic claimed to have put a new MPEM in the ski and had it programmed with the key. I would get 2 beeps with it before and after this problem occurred(I would try putting the key on while the ski was turning over by itself and it would give me 2 beeps) I have bought a new solenoid, tested the start/stop switch, traced the grounds to make sure they were good(only know of 1 that is on the motor) checked the stater to see any wires out or metal shavings at the bottom, and the ski also has a new wiring harness. I had an electrician see if he could find the problem and he traced it back to the MPEM. Usually I would've taken it back to the mechanic but he had just gotten into a really bad motorcycle accident so that option was out the window. Appreciate any help!
1996 720GS turns over consistently
- Thread starter hondaxl80
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- BiRkS_
Active Member
Get a test light, or volt meter, and check for voltage at the starter solonoid trigger wires (little clip with a black and yellow/red wire I believe? If you hook up the battery and get voltage, then trace the issue foward. Disconnect the start/stop switch. See if the voltage drops, if so, its a switch. Isolate the MPEM. (unplug everything) You said the ski got a new wiring harness. Is it the correct one? Is the MPEM the correct one? I would focus on the start/stop switch and the start circuit.
Best thing to do is just work backwards from the starter solonoid. Find out what is giving the solonoid power. Does this MPEM have relays in it? Sometimes they go bad and stick on. Food for thought.
Best thing to do is just work backwards from the starter solonoid. Find out what is giving the solonoid power. Does this MPEM have relays in it? Sometimes they go bad and stick on. Food for thought.
Dr Honda
Well-Known Member
Unfortunately... I've heard about this more than once. It's a failure in the MPEM.
Did you charge the battery when you got home? (and start it with the charger on it?)
But... if the tech just replaced the MPEM... I would be going back to him, and saying it's defective. If it's an aftermarket unit... they all SUCK. I hear about them failing all the time... and most don't work out of the box.
Did you charge the battery when you got home? (and start it with the charger on it?)
But... if the tech just replaced the MPEM... I would be going back to him, and saying it's defective. If it's an aftermarket unit... they all SUCK. I hear about them failing all the time... and most don't work out of the box.
DJMky
New Member
Had this problem back on a XP I had. Found out it was the MPEM. It would start turning over in the middle of the night and scare the dog which in turn would have him going ballistic as my skis are kept in the garage and he could hear it trying to start and freak out. After a few nights of this crap I figured out what was happening 
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