Hi everyone,
I recently bought a 1999 Sea-Doo Sportster 1800 with twin Rotax 717 engines. I’m currently trying to diagnose a no-start condition and would appreciate any insight.
Here’s what I’m experiencing:
From what I understand, on these models:
Could it be:
I recently bought a 1999 Sea-Doo Sportster 1800 with twin Rotax 717 engines. I’m currently trying to diagnose a no-start condition and would appreciate any insight.
Here’s what I’m experiencing:
- No beeps at all when I insert the DESS key — completely silent.
- Starters work: when I press the start button, both engines crank normally.
- No spark on any of the 4 spark plugs.
- Battery voltage is good (12.68V), and I’m getting 12.68V at the coil input.
- The same problem affects both engines, which suggests a central issue.
- Battery and starter system seem fine — engine turns over strongly.
- Radio is getting powered when I place the key but that's about it.
From what I understand, on these models:
- The magnet in the DESS key allows power to the MPEM (activating the starter circuit).
- But unless the key is recognized, the MPEM blocks ignition/spark.
- So it seems like the DESS key is not being recognized, even though the starter works
Could it be:
- A bad DESS post (still detects magnet but fails to transmit key data)?
- A dead or unprogrammed key?
- A partial MPEM failure?
- Or even a broken data wire between the DESS post and the MPEM?
- Something completely different?
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