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View Full Version : RPM - What is normal?


Cousin_Jeff
07-02-2007, 10:31 AM
I have an '02 197. Recently I had some dings in the prop repaired by my local shop. (I have since learned that was not the smartest thing and wish that I had sent it directly back to OJ). Anyway, I don't believe that I am getting the same torque out of the prop and the RPM's seem higher to me than they were prior to the repair.

I honestly don't remember what it was but 3000 RPM's was a lot closer to 30mph than the 25mph I have now if I recall correctly. My question is, "Is 25 mph normal to be reving to 3000 RPM's?"

- Note to moderators - I searched for this topic and did not see it directly. I apologize in advance if this is a duplicate thread.

Andyg
07-02-2007, 10:36 AM
Cousin_Jeff,
What engine/tranny combo are you running. Do you know what size prop you have?

andyg

Cousin_Jeff
07-02-2007, 10:45 AM
I have the 310hp engine with 1:1 transmission. If that helps any.

trickskier
07-02-2007, 11:04 AM
Really need to know what size prop you're running to give an educated guess.............

Cousin_Jeff
07-02-2007, 11:25 AM
The prop on there currently is a 13 X 13. I am looking into this a little further b/c the owners manual I have has a grid that states that a Prostar 197 with my engine should have a 13 X 14. I just called OJ and they assured me that it should be a 13 X 13 which conflicts with the Master Craft spec grid.

Andyg
07-02-2007, 12:35 PM
Is it a 4 blade or 3 blade? Is it a CNC machined prop? You can tell if it is a CNC prop if it has machining grooves in it. Otherwise it will be very smooth with no grooves.

One of the best ways to tell if your prop is running appropriately for your engine/tranny setup is to do a wide open throttle run, WOT. What is your speed at WOT and what are your RPMs at WOT. The RPM range for your setup should be 4400 to 4800 RPMs. If you are not in that range then your prop needs to be repaired again.

Andyg

Cousin_Jeff
07-02-2007, 01:05 PM
Thanks for the help. I am now a little more confused than before. I sent an email to OJ and they responded that the stock prop for my boat is a 13 x 14. This is consistent with the MC users manual but different than what OJ told me on the phone. Perhaps I just got an anxious receptionist earlier. I believe the written email from Eric at OJ and the MC users manual.

Now this is the issue. I believe that my dealer put the wrong prop on my boat when they got it back from their subcontractor that reconditioned it. There was a mix up somewhere I believe b/c I believe I took in a 13 X 14 and my boat now has a 13 x 13. I have a call into my service dept at the dealer now. More to follow.

Cousin_Jeff
07-02-2007, 01:05 PM
It is a 4 blade.

Cousin_Jeff
07-02-2007, 01:06 PM
The prop I took in had grooves in it and the one on the boat now does not. That was the first thing that had me thinking this wasn't my prop b/c I distictly remembered it having grooves.

WilliM1940
07-02-2007, 01:24 PM
Pi$$es you off doesn't it? Next time I send in a prop I am going to stamp my initials in the hub.

Andyg
07-02-2007, 01:29 PM
The prop I took in had grooves in it and the one on the boat now does not. That was the first thing that had me thinking this wasn't my prop b/c I distictly remembered it having grooves.

Sometimes when they repair a prop the machining grooves will disappear from the area that the repair was done, but the rest of the prop should still have the machining grooves in it.

Cousin_Jeff
07-02-2007, 01:30 PM
Willi, that does kind of sum it up. Not only did they WAY over charge me, now I have the wrong prop.

I will keep you posted as to what happens once I hear back from the service dept.