M40c low RPM at WOT

[Scottkirkman1]

I have this motor on a 1648 tracker mv hull. It's light as heck. I'm running a 14 pitch prop. Right now the motor sits too low, the cavitation plate is about 2 inches below the bottom of the boat. I have a jack plate on the way to fix this. Yesterday I took the boat out to see how it ran, best I could do was 25 mph at 3800 RPM, per a tiny tach. I had a decent load, 2 adults, 2 children, a dog, and an ice chest. Hole shot was pretty decent. Motor is healthy and running well. Will bringing the motor up raise my rpm's by almost 2000? Or am I going to be looking for a new prop too? I know I probably just need to get the plate on and experiment, but I thought I'd get some opinions here too.

 

[pvanv]

Yes, low jack height will cause that kind of symptom. Probably need less pitch as well.

 

[Scottkirkman1]

Ok. As I'm playing with motor height and props, do I need to regulate RPM's or is there a rev limiter built into the cdi unit?

 

[pvanv]

A model that ancient may or may not have a limiter.