Cruise RPM?

[RK]

Last winter I bought a Wellcraft 21 foot center counsel [ 21 fish ] it didn't have an engine so I bought a used 2001 FICHT 200. I am absolutely amazed at how perfect this thing runs, how little fuel and oil it uses, and the power! WOW.. Anyway I use it on lake Huron. As such many times you don't really want the cruise speed over 25 mph as the waves can get too big to go any faster comforitably. The RPM's at 25 mph is only about 2000. The bow is down and it's on a plane just fine but I'm wondering if I am significantly sacrificing fuel economy by running it at such a low RPM??? What is generally thought to be the best cruise RPM isn't it around 3500?? Thanks

 

[Chris1956]

That is a very low RPM for that speed. What prop pitch are you running? I would expect your RPMs to be at least 3000 for that speed.

 

[RK]

That is a very low RPM for that speed. What prop pitch are you running? I would expect your RPMs to be at least 3000 for that speed.

14 1/4 x 21 hmmm I wonder if my tach is bad? I should have checked what it was WOT. I've been boating my whole life it doesn't sound like real low RPM's to me so maybe it is a just a bad tach.. is 3000 rpm about the best cruise rpm?

 

[1983 ercoa 21']

From what I understand you don't want to be lugging the motor or working it hard as long as you feel the motor is doing it at ease you should be fine but surely someone with more knowledge will chime in . But 2500 does sound pretty low for 25

 

[Chris1956]

I run a 21P prop on my '98 Johnny 150HPV6, on a 21 footer. 25 MPH is about 3100 RPM.