1997 SeaDoo XP MPEM issue with start relay circuit, all other functions work.

[WaterJet]

Hi Everyone,

I have struck an interesting electrical issue on my '97 XP. It appears to be an issue with the circuit in the MPEM that activates the starter motor solenoid. The problem occurred when I went to start the ski back up. I installed the key and got the 2 beeps, then upon pressing the start button nothing happened, I didn't hear any relay click so replaced the starter motor relay. After replacing the relay the problem remains. The start/stop switch works because without key installed, pressing it will fire up the gauges/vts. I can start the engine by pressing the start button while bridging the relay terminals to turn the engine over, and the engine runs perfectly, in fact this was how I managed to start and ride back to the boat ramp when it failed, VTS and gauges work. So everything functions apart from this starter relay part of the MPEM, all connectors are clean.

Is there a smaller relay or transistor switch inside the MPEM, which can fail to cause this problem?

Anyone know the location of the suspect components that can fail to cause this MPEM issue?

Thanks

 

[WaterJet]

bump

 

[KevinT]

I feel your pain. I have the same issue on a 1998 XP Ltd. I'm sure there's a reed relay embedded in the potting compound like I used to replace all the time on Navy gear years ago.

The 98 MPEM is different but same root cause I'll wager.

I was only able to find it by finding the output from the MPEM on the 26-pin connector and patching in a test lead. I can see the contacts bouncing as the starter runs intermittently. (On mine the starter cranks but only for a couple seconds. Sometimes the engine starts, sometimes it doesn't.

I talked to Westside Power Sports. They repair some MPEM problems but not this failure mode. They will sell you a working used MPEM with a warranty. I already have a local guy for used parts.

I have mine running with one of the aftermarket MPEMs from Brazil. Again - yours is different but just for general info. Those run several hundred dollars, as does a used one.

If someone would tell how to get the potting compound out and print a map of components on all the MPEMs a guy could take a stab at replacing the relay. I'd consider patching in a separate start button. If Seadoo hadn't gotten fancy with having one button be start and kill both, it would not be routed through the MPEM and the problem would not happen. You'd simply have two buttons.

 

[SpitandDirt]

I feel your pain. I have the same issue on a 1998 XP Ltd. I'm sure there's a reed relay embedded in the potting compound like I used to replace all the time on Navy gear years ago.

The 98 MPEM is different but same root cause I'll wager.

I was only able to find it by finding the output from the MPEM on the 26-pin connector and patching in a test lead. I can see the contacts bouncing as the starter runs intermittently. (On mine the starter cranks but only for a couple seconds. Sometimes the engine starts, sometimes it doesn't.

I talked to Westside Power Sports. They repair some MPEM problems but not this failure mode. They will sell you a working used MPEM with a warranty. I already have a local guy for used parts.

I have mine running with one of the aftermarket MPEMs from Brazil. Again - yours is different but just for general info. Those run several hundred dollars, as does a used one.

If someone would tell how to get the potting compound out and print a map of components on all the MPEMs a guy could take a stab at replacing the relay. I'd consider patching in a separate start button. If Seadoo hadn't gotten fancy with having one button be start and kill both, it would not be routed through the MPEM and the problem would not happen. You'd simply have two buttons.

The original poster has an aftermarket MPEM illustrated in the pictures made by Reitron of Brazil and importedby WSM. It's definitely not oem because it would clearly have "Made in Canada" on the shell.

As for your comments about the potting compound...it doesn't come out without a fight. It's doing what it's intended to do an that is to protect the components from water intrusion and harmful vibration. The point of making the MPEM (with DESS) was to make it easier for dealers to sell new units when old ones came in for maintenance, or just to get a new key programmed. However, I can guarantee that under the potting compound of the MPEM there is nothing but semiconductors and maybe 1 or 2 automotive style relays. The only glass reed switch is embedded inside the DESS post where the key is installed.

Printing a map of components is not a small endeavor. There are at least 350 discrete smt/smd components on the pcb. The earlier MPEMs might only have about 250 given the use of standard "throught-hole"components and the simple design where DESS wasn't a thing yet.

Mapping a board is tedious work when the circuitry is proprietary in design and SeaDoo(Mega-Tech Electro) isn't handing out that intellectual property anytime soon.

I know this for a fact because I've completely mapped out a 2000-02 GTX MPEM. There's a LOT more to it than you think.