2000 seadoo challenger 2000 need new ecu i think?

[ynks972]

HI everyone new to this forum, so i just bought a 2000 seadoo challenger 2000 with a mercury 240 efi engine i bought the boat thinking everything was working fine or so i thought but found out yesterday when he was doing a tune up that two of the spark plugs were not working the middle one on each side and the mechanic said i need a new ecu was wondering if this sounds right to anyone because the boat starts up and revs up fine when on land, and if anyone is selling one or knows where i can get one feel free to respond also

thanks for any help in advance

 

[johnhibbs]

I would say it is very unlikely it is the ECU. Under the flywheel there is something called the trigger assembly that has 3 coils. Each coil controls the spark to 2 cylinders - one on each side. It is cylinder 3 and 4 in your case. The Stator Assembly is also under the flywheel. You should get the Mercury service manual for this engine. PN 90-877837. Maybe this site has it to download. The manual has all the tests you will need to find the problem.

Here are the easy tests:

The trigger assembly has six color coded wires. You will need an ohm meter to check it. It shold read between 1100 and 1400 ohms between: brown and yellow, white and red, purple and blue.

The stator also has some resistance measurements.

I also saw this in the manual: "A shorted Stop Diode in CDM#1 or CDM#2 would prevent CMD #3 and #4 from sparking.
The CDM is the Capacitor Discharge Module near each spark plug. The manual tells you how to ohm out the CDM. You could also swap them around to see if the problem moves to some other spark plugs.

 

[johnhibbs]

It might also be something simple like the snap-on connector to one of the CDMs is loose. One CDM will affect more than just that one CDM.

 

[ynks972]

im definitely going to get my hands on the manual, he already ruled out the stator and as for the cdm he never mentioned anything about that ill mention it to him tomorrow though and see if he can look into it, also do you leave your challenger docked for the season?