95 speedster fresh mpem conversion, now issues please help

[dbrisson]

Alvright, this is gonna be along one...

Ordered new mpems from Dominic (very happy with service) installed mpems, started the engines and ran for a few seconds to make sure wiring was OK, both engines fired up. Went to the lake and decided to run the boat on the trailer in the water to test all the systems and make sure everything was 100% before going out... this is where the problems started with port engine, it ran for maybe 30 secs then died, realized fuel shut off was set to off, so I turned it on. When I went to fire the engine up all I got was a very short crank, so thinking it was bad solenoid I jumped it and engine rolled over but did not start, tried a few more things, got frustrated and just gave up. Took the boat home and left it for a couple days.

Finaly went back to it today and did some testing, if I unhook the ignition (black and red) wire going to mpem I get spark, and the engine fires right up when solenoid is jumped, if I connect the start solenoid connector from port engine and connect it to starbord engine it rolls over beautifully, and vice versa, it just doesnt like to turn the engine over in its proper location.

So the 2 issues I have are
-no spark when connected to mpem
- and short crank when connected to proper solenoid, I've replaced solenoid as well, and tried new engine ground.

Any input would be great

 

[Dr Honda]

Sounds like the new MPEM's are bad. Are these aftermarket units?

 

[dbrisson]

Its the conversion from seadoosource, one mpem is working great, the port side seems to ground the ignition so I have no spark, as soon as I unplug it, fire right up, not sure what kind of testing they do before sending them out, may just wire another switch and run the boat, sick and tired of working on it

 

[dbrisson]

Played around with it again tonight, found that if I unhook the coil ground plug to the mpem, everything works perfectly except I have no shutoff, so I'm running a ground switch to the front and live with it, I need to get this thing in the water, I've spent more hours bent over the back seat working on it then I have sat in the driver seat in the water.... hopefully its happy boating this weekend

 

[Dr Honda]

NO!!! that's extremely bad.

1) You are sending upward of 300 volts to that kill switch. You can electrocute yourself. The MPEM isolates you from that hazard.

2) The MPEM is the rev-limiter. If you hop the hull out of the water, or develop cavitation... you can quickly rev the engine past 10k RPM's, and it will scatter parts everywhere.

The aftermarket MPEM's suck. We see it here all the time, and they are hit-or-miss. Personally, I would take a chance with used OEM's over the aftermarket units.

But, sorry you are having issues.

 

[dbrisson]

So I went ahead and wired it the way I wanted it and had the best weekend, this is the first time that I've used this boat in over a year.

As for the 300 volts, there is nearly no amperage going through that wire so the chances of getting electrocuted are slim to non, you'll get a good zap if you decide to become part of the circuit though. I build ultralights with rotax engines and this is the way we wire the kill switches, and we've never been electrocuted. This time I used a 2 way spring loaded switch so I could kill both engines with 1 switch, worked awesome.

as for the rev limiter, that originally was my biggest worry, but after having the boat out in the water this weekend I'm not worried anymore, I've got a 2 year old and a 4 year old in the boat, if I jump the boat, the engine over revving is the least of my worries, my wife would do more damage then the engines coming apart. As far as cavitation, I sucked up some weeds this weekend and never over revved the engine.

These boats dont need an MPEM to run, the 2 strokes are self sufficient, the only thing the MPEM's are good for is the rev limiter and causing a bunch of greef.

I'm still very happy with the job Dominic at seadoosource did wiring everything in, he saved me a few hours of work and the boat is finally getting used.

 

[Trademark1564]

Hey I am having like the same problem on my 97 speedster, it's like a super short crank and no turn over on either engine, if I find answer i' ll get back to you

 

[Chrisshep]

I just ordered that same kit from Dominic but need some help put the finishing touches on getting it wired up. I was not the one to unhooked the old MPEM so I am unsure on how it was previously wired.

Where does the black wire coming out the center starter solenoid( I think booster solenoid) wire go?

My previous post.
http://www.seadooforum.com/showthread.php?54694-MPEM-Help&p=277420#post277420

 

[Trademark1564]

I think I grounded them out on a post inside the box where the other grounds are, I have the twins, so not sure if it's the same