23 mirage plus to 25 mirage plus - strange results
 

I tried changing a 23P Mirage Plus this weekend on my 242 Formula. I need to reduce my rpm some. The 23P revs at about 5600 rpm, but the 25P Mirage Plus dropped the rpm down to 4750 rpm. With the 25P is feels like the motor is under a huge load. What would cause such a drop in rpm?
Both props are untouched out of the box. I would like to get my rpms to about 5150 if possible.
With the 23 mirage plus I see 68 on a GPS, with the 25 I see 65. I tried 2 different 25s also.

Thanks

Re: 23 mirage plus to 25 mirage plus - strange results
 

If both 25's are brand new. I'd say something was fishy with the 23.

Re: 23 mirage plus to 25 mirage plus - strange results
 

I had the 23 checked out and I was told the prop was not modified or fixed in any way. Also tried a modified 23 mirage (non plus) with some extra cup added with the same results.

Re: 23 mirage plus to 25 mirage plus - strange results
 

I would check your tach.

Julie

Re: 23 mirage plus to 25 mirage plus - strange results
 

Digital tach verified RPM numbers

Re: 23 mirage plus to 25 mirage plus - strange results
 

Then I would inspect the propellers...something is giving you false readings. The difference should be 400 RPM difference between the 23P and the 25P and this formula is solid.

Julie

Re: 23 mirage plus to 25 mirage plus - strange results
 

Thanks, I'll look into both props a little closer.
I was able to get 4900 RPMs out of the 25 plus yesterday, still only ran 65 compared to 68.7 @ 5200 with a heavily cupped 23

Thanks for all the input