2000 Seadoo Challenger 240efi Mec engine

[elvwilliams]

Hi guys, I have a Seadoo challenger which has been a awesome boat for Loch Lomond. It's been running great, new plugs, fuel filter etc all before going in the water.
Yesterday it was starting and running fine, used it for around 2 hours towing. We tried pulling another skier up when we encountered the problem. Trying to pull the skier up, rev'd fine then began to miss fire which wouldn't clear. Shut the engine off and tried again, which the engine again Miss fired. We changed all the spark plugs, still missing on acceleration and throttle.
The engine starts and stops fine, runs fine on a low rev but when trying to accelerate begins to miss fire and will not rev or clear and speed up.
I have ordered new ignition leads in case they are breaking up or faulty.

Any other help would be greatly appreciated, thank you in advance.

Steven Williams

 

[kozzy4444]

Ever figure out a "fix" for this issue???

 

[elvwilliams]

Nope, ended up taking it out the water. Still stuttering and misfiring when hot and throttling

 

[bhatch21]

Sounds like your misfire might be caused by the mystical Throttle Guardian. Do some searching on here for it. I remember one guy had a write up with a picture of it and how to remove and bypass it. It was a safety feature not found on the wiring diagram that cuts out spark to the engine. I believe it's a small black box found behind the steering wheel on most boats. Good luck.

 

[bhatch21]

Forgot, I've seen them for sale on ebay. Maybe that's where I remember the picture.

 

[poppie]

Probably the trigger coil located under the fly wheel. The manual specifies how to check it. Also do a visual check of the wires. The wire insulation frequently goes bad.