Computer limiting RPM's on Pro XS motor?

[Mike Wagner]

Hi,



I have 2 hours on my new 150 PRO XS, and I have been following the manual regarding break in. The book says to vary your RPM's between 3000 and 4500, but the computer would not let me go over 4200. Is this normal?



Thanks,



Mike

 

[Jim C. Jackson]

That is interesting to know, I am trying to learn as much as I can before I get mine. Were you trimmed up? Hopefully Bob will chime in soon.

 

[Bob Bourget2]

It is NOT rev limited to 4200 rpm. Could you give me more specifics relative to boat, prop, mounting height, etc?

What is MOST LIKELY happening is what Jim touched on. On some hi-perf boats, when the motor is trimmed under fully, the boat plows so much there is a tremendous load on the motor to the point of extreme lugging. If you are running WOT in this fashion, you can't expect to achieve top rpm.......pay attention to break-in as outlined......

 

[Mike Wagner]

Bob,



It is a Nitro Z7 with a Tempest 24 prop. I do not have a jack plate and have no idea about what the mounting height is. It is however they rigged it from the factory.



I now have 3 1/2 hours of break in, running fulling trimmed down to load the motor as the manual says. I have been varying the throttle every 2 minutes within the range of 3000 and 4200 RPM's. The book says to vary between 3000 and 4500 during break in, but it is not possible for me to get that high. My top speed trimmed down is 41 mph GPS.



I hope I have been doing the right thing running trimmed down at those RPM's to break in the motor. I have always stayed within the RPM range the book says, but it sounds like I may have had it at WOT and not even known it- I just assumed that 41 mph would have been about 3/4 throttle based on the speeds I expected to get out of the boat. I have also been heat cycling as you have previously advised.



For how many more hours should I keep running trimmed down and varying the throttle? The book says there is a 4 hour break in period, but I have heard the number "10 hours" used by many people. What are your suggestions?



Thanks,



Mike

 

[Bob Bourget2]

Follow the book to the letter....then run it like your being chased by a Cop down the highway at triple digit speeds looking to give you back your EX.....LOL!!!!

 

[Mike Wagner]

Thanks, Bob. I will try trimming it up next time after I have followed the 4 hour break in the book calls for. I will post again if the numbers still don't seem right.



Mike