97 speadster cuts out at 4000rpm

[Mariod45]

So carbs rebuilt twice, stator replaced, head replaced. Still doing the same thing as soon as it gets to 4000 rpm, also replaced the brain, when it cuts out at 4000 rpm it Will restart right away. What to check next?
I'm thinking replace all fuel lines?
Any suggestion would be appreciated.

 

[mikidymac]

Does it just shot off like someone pulled the kill switch or does the engine die like it's running out of fuel?

 

[Mariod45]

Shuts off like I pulled the kill switch

 

[Mariod45]

Although one time as the engine cut out. Rpm gauge went to almost 0 and engine come back alive. Only happened once though.. But it fires right back up.

 

[JeremyD615]

When you say you replaced the brain, what did you actually replace? Was it components or the whole grey box? Have you pulled the red wire from the voltage regulator to see if that clears it up? Of course you won’t be charging the battery while that wire is disconnected...

 

[Mariod45]

Just the mpem? Did not replace other parts.
I have not tryed that. But will give it a try.

 

[Mariod45]

Won't be able to test till next week. Il be up in sac on my boat for the weekend

 

[mikidymac]

Does your boat use the DESS lanyard key?

 

[Mariod45]

Yes it dose

 

[mikidymac]

I have seen a few of the skis that will shut off when the DESS post is going bad and then start right back up. It basically is like someone just pulling the lanyard and they die.

 

[Mariod45]

Did think of that. But there's only one Fess key that works boath engines, and the right side has no problems, so not thinking Dess or it should happen to boath engines I would think.

 

[mikidymac]

These boats are just silly, glad I only have skis.

 

[Mariod45]

You are right finaky darn things

 

[funsummerahead]

A 1997 has a monster MPEM for 2 engines with all the electronics... Lots of wires and connections in there and quite a few going to both engines too. MPEM - Multi Purpose Electronic Module and other manufacturers call it a CDI box. Ski Doo / Sea Doo say MPEM. Whatever.

1 DESS key for 2 engines and ONLY 1 cuts out at 4K …?

From what I've seen when the MPEM goes bad BOTH of engines won't run.

So try this -

1 - Remove the DESS key.
2 - Disconnect both batteries - negative first.
3- Clean / wire brush and Dielectric grease the connections on the MPEM wires and ALL wires 2 both engines.
4 - Put them back together. Positive battery posts first, then negative.
5 - Try it out and let us know...

 

[Mariod45]

A 1997 has a monster MPEM for 2 engines with all the electronics... Lots of wires and connections in there and quite a few going to both engines too. MPEM - Multi Purpose Electronic Module and other manufacturers call it a CDI box. Ski Doo / Sea Doo say MPEM. Whatever.

1 DESS key for 2 engines and ONLY 1 cuts out at 4K …?

From what I've seen when the MPEM goes bad BOTH of engines won't run.

So try this -

1 - Remove the DESS key.
2 - Disconnect both batteries - negative first.
3- Clean / wire brush and Dielectric grease the connections on the MPEM wires and ALL wires 2 both engines.
4 - Put them back together. Positive battery posts first, then negative.
5 - Try it out and let us know...

Thanks I will try that as well
next monday, for now enjoying the 80 deg weather in Sac this weeken on my Carver.

 

[funsummerahead]

Well it's 61 F in Northern Illinois right now aaaaaand a possible 4 - 10 inches of snow over the weekend I hear.

 

[Mariod45]

Oh sorry to hear that. But glad its not me.
Hey some people love the snow. I'm not a fan. Grew up in that stuff.

 

[Sportster-2001-951C-Stock]

Some have those divorced fuel pumps known to be a little on the low side of enuff capacity when they age.

Air leaks in the fuel lines, especially the fuel strainer cup gasket.

Otherwise yeah, some kind of intermittent electrical issue associated with the Rube Goldberg MPEM. Curse the concept of DESS.

 

[Seadoogirl72]

Hey guys..just curious...what is the MPEM and where would that be on a sea doo challenger 2006? I too had an issue this weekend... new battery and brand new key and no gauges working and the engine did like 8 beeps then shut off. Replaced fuse near motor for gauges and still not working. Started back up and ran for about 45 mins, sounded good no alarms nothing... Im thinking its the key or a wire?

 

[Mariod45]

So after doing a test run yesterday, the port motor still dies after 4000 rpms , the engines sound good, funny thing is when I go over the 4000 rpms it drops down and pulling the throttle cable back and then move it forward it still runs back up to 4000 rpms, so it's not completely cutting out, could this be the Rev limiters cutting in? One Sea Doo mechanic thinks it's the Crank shaft seal. Any thoughts? I have changed out the MPEM, stator, swapped out the head, changed out the coil, checked out the dess post and wires, still doing the same thing.

 

[POPPS]

Had a J boat once, similar symptoms, stator fine, but battery not charging, reg tested positive, but fuses in the external fuse cluster before the battery were corroded, replaced them and ran like a champ.