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Old 01-06-2020, 11:23 AM
Fishindave9 Fishindave9 is offline
Join Date: Mar 2019
Posts: 6
Default 2005 26fs repowered with Merc 250's

Well, I've been lurking and watching and finally had to put this out there.
I purchased this boat in Feb 2019 with the standard 2005 Yamaha F225's and ran it for a summer, but was never just that impressed. Had standard SWS 19's and topped out at 48 mph at 6k rpm. Boat always stays loaded and it was taking 4600 rpm just to get 35 mph. I tried Ken's Rev4 19p and loved the way it ran with those props, but I still decided it was time for a change.

Decided on the 250 Mercury V-8 as they are still lighter than the F225's were.

Motors were ordered in October and they arrived December 1st. Full electronic controls with the Mercury DTS screen.

First test was just before Christmas with Rev4 23p on the 1.75 gear ratio.

My questions come in on the props - We test ran 2 people full fuel and no real gear. We ran with the computer hooked up as the computer shows the Linear for the motors with the goal being of the demand = output.

First of all, the boat was a rocket. We warmed them up and tested for a while and 3500 rpm was 36 mph. 4000 rpm was 42 mph.

Trimmed in, could only spin 5100 at about 52 mph, but trimmed way out we got 5585 at 57.2 mph.

I think overpitched, but I'm looking for input on performance and slip ratio. The Linear readings on the computer showed higher demand than output (say 90% demand with 80% output), but when put on the pins, they matched up 100%/100%.

According to the Mercury prop calculator that top end is at 18% slip. 4000 rpm was 16% slip.

We are currently going to a 21p rev4 and going to cup it to 22p. Should free up the motor just a bit. Any input is appreciated. The boat does have bottom paint. Motors are set 2 holes up.

Last edited by Fishindave9; 01-07-2020 at 01:15 PM.
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Old 01-08-2020, 05:10 PM
RSmith RSmith is offline
Join Date: Jul 2009
Posts: 19

Call Ken at prop gods, he will tell you what you need. I'm running rev 4 19 on my 26 with mercury 225. You might want to try the 21s before you cup.
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Old 01-08-2020, 06:19 PM
Rich53 Rich53 is offline
Join Date: Oct 2012
Posts: 243

I thought they made the Rev4's in even pitches as well, for instance on my 26 with the Yamaha 250's (3.3L) i am running 20's, isn't there a 22" pitch Rev4?
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Old 01-08-2020, 08:43 PM
Meidus Meidus is offline
Join Date: May 2015
Posts: 27

this was with 21 rev4
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Old 01-09-2020, 06:16 PM
Fishindave9 Fishindave9 is offline
Join Date: Mar 2019
Posts: 6

Thank you everyone. I have a set of 21's on the way and my prop guy is working the 23's to a very custom set of 22's.

Expect to test by next weekend with at least one of the sets and will keep you posted.

Meidus: hell of a video. I've personally never owned a boat where the RPMs match speed so this is certainly a new feel. Even my little Blazer 2170 is 4000 rpm/35 mph. The engines sound great!!
Gulfport, MS
"Second Wind"
05 26fs
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