Mystery fault Challenger 2000

[Canadian06]

I have a 2001 Challenger 2000 with a 240hp Merc that is driving me nuts. There’s a problem with the engine going into what appears to be limp mode and I have no idea why.

the motor will run great all day as long as it isn’t turned on and off a few times while on the water. After a couple restarts it will limit the RPM to around 1500 and I have to limp back to the launch.

I did an experiment to figure out if the water was causing the fault. If I start the motor in my driveway and then immediately turn on the garden hose it will run great. If I turn on the garden hose first, then start the engine it runs like garbage and acts just like it does on the water.
Has anybody experienced this or have any ideas

 

[Tim75]

I have a 2001 Challenger 2000 with a 240hp Merc that is driving me nuts. There’s a problem with the engine going into what appears to be limp mode and I have no idea why.

the motor will run great all day as long as it isn’t turned on and off a few times while on the water. After a couple restarts it will limit the RPM to around 1500 and I have to limp back to the launch.

I did an experiment to figure out if the water was causing the fault. If I start the motor in my driveway and then immediately turn on the garden hose it will run great. If I turn on the garden hose first, then start the engine it runs like garbage and acts just like it does on the water.
Has anybody experienced this or have any ideas

Check for corrosion damage to the adapter plate and gasket under the engine.

Any water source that can spray water into the exhaust. Check that your plumbing is correct.