Troubleshooting while the engine runs on the trailer, water flow

[2x2smoke]

97 challenger 1800 with the 787 motors

I'm working through getting a neglected boat running. Both engines start for me but they aren't revving past 3500 rpm. I'm going through the process of troubleshooting with the boat in the driveway.

I'm aware of the flushing with garden hose procedure where you are running the water backwards through the motor to flush things out. Is the motor supposed to be able to rev normally with the water running in reverse direction?

I'm thinking of making a fitting that fits into the supply orifice and running water through the normal operating direction. That way the exhaust water regulator will be doing its thing and maybe I can fiddle with things not worried about the engine overheating

Both my drives are removed so I would run the water into the hull orifice

 

[nisjeep]

Very normal to run at 3500. Tried taking it out of neutral ? Also you cannot "run as long as you like" out of water. The water preassure actually keeps the impeller tight on the thrust race. Prolonged running may damage your impeller/ shaft assembly.

 

[nisjeep]

Sorry. Did not read the last bit. I see your drives are removed.

 

[2x2smoke]

I forgot about the neutral switch! Is it normal to have 3000 rpm idle out of water then rev limited in neutral to 3500 rpm?

 

[nisjeep]

3000 out of water is spot on . The water drag will bring it down to acceptable levels.