Senior Rotax EVO ECU plug/connector problems

[Alex Matthew]

I have a new Rotax Senior EVO motor, and it ran great at the beginning of the season. However, two weeks ago, the ECU plug/connector came apart and the small plastic clips on the plug (that snap the one into the other) broke. Obviously, without the ECU, the kart won’t start or run. As a fix, we have moved the plug position vertical, and then used tape and zip ties to make sure the plug/ connector is snug. This seems to work OK, except you need to go through this exercise every sessions or two. Also, the motor (because of the ECU issue) will overly bog in low speed corners. Our track has had at least 6 upgrades and/or new EVO motors do this, and it seems widespread. It has become very frustrating. A few questions:
1. Has anyone else had this problem? Does anyone know if MaxSpeed is aware or what they are doing to remedy the situation?
2. Does anyone have a good/better fix for this?
Thanks! Appreciate the help.

[Michael Cohen]

Alex;

We have had a number of people at our track with the same issue. See my post at http://ekartingnews.com/forums/topic/rotax-evo-parts-failing/

It seems to be all in the plug connection…..

Not fun at all. I did call MaxSpeed and they said they were not aware of any issues, furthermore although I purchased my EVO Upgrade through MaxSpeed and they told me to deal with my local dealer…..

 

[Andy Rylance]

Interesting about bogging in low speed corners, my son has been complaining frequently about the same. I’ve been playing with air/fuel mix and needle settings to fix. On the wiring harness front, we had a DNF this weekend because of a failure of the low voltage connector to the coil in the wiring harness. I’ve heard this has happened to a few people now.

[Scottie Melancon]

Haven’t heard of issues with ECU’s at our track, but I was recently informed that Max Speed is now shipping coils with a rubber bushing that you place between the coil housing and bracket. I’m guessing it’s the same as what is provided for the ECU to minimize vibration. This person told me that there have been  some instances where the resin seals have cracked on coils.

[Andy Rylance]

There is a post on the Maxspeed website that states it is now mandatory to include the rubber buffer. The ECU buffer is no good as the thread is too short. I used a buffer from the old coil. While warming my sons engine at the track this weekend, I noticed something strange. When I reved it, the coil would turn about 15 degrees on the mounting bolt. I checked the tightness when I got back to the pit and it was very tight. I added the rubber buffer and it stop the twist. I’m guessing that’s why they have mandated its use.

 

As a point of note, there were multiple harness failures this weekend. One literally went up in flames, another couple were identified as causing performance issues. Another had a failed grounding connect.

[Scottie Melancon]

I’ve also noticed that the coil rotates on the mount of my kids junior rotax when warming up.

Now your the second person to tell me that there is a mandatory requirement for installing the isolation bushing but I’ve yet to find anything on the Maxspeed website even mentioning the issue much less requiring a modification.  The last bulletin on July 11 doesn’t appear to have this requirement. Am I missing something?

[Andy Rylance]

Hmmm… strange, I just took a look and it’s not there any more. I saved the original PDF and also printed it out. It is marked as Bulletin 1, 2015 02 13. It states, “As of March 30, 2015 it is mandatory to fit the ignition coil by means of a Rotax original rubber buffer to the bracket….” I suspect it have been removed as the buffer shown seems to be the same as that used for the ECU and as I mentioned, the thread on this is too short for the coil.

[Scottie Melancon]

I believe Maxspeed recently updated the entire website. It may have not made it back to the new site. Considering that it From a bulletin in February, it may have been included in the 2015 regs that were published in March or April?

[Scottie Melancon]

Yep. Page 24 of the 2015 Reg shows the bushing.

[Josh Buttafoco]

Spread the pins out from each other in the ecu, this causes the pins to be a bit more bound when you connect the harness plug. Also make sure none of the pins in the harness plug are loose or pushed back. Put dielectric grease in the plug before final connection.

Also so a good idea to wrap the power wires with electrical tape or shrink wrap under the on/off/start dial.  If the battery box top becomes unclipped and arcs the leads onto the actual battery box, you will fry the harness.

These 2 fixes have taken care of 90% of the issues we have come across.

 

 

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