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Old 01-06-2020, 11:23 AM
Fishindave9 Fishindave9 is offline
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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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  #2  
Old 01-08-2020, 05:10 PM
RSmith RSmith is offline
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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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  #3  
Old 01-08-2020, 06:19 PM
Rich53 Rich53 is online now
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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
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https://www.youtube.com/watch?v=dGGLOM68WXs&t=185s

this was with 21 rev4
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  #5  
Old 01-09-2020, 06:16 PM
Fishindave9 Fishindave9 is offline
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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!!
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05 26fs
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Old 04-04-2020, 09:29 PM
Meidus Meidus is offline
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Any new numbers?
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  #7  
Old 04-26-2020, 07:53 PM
wadams35 wadams35 is offline
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Default Updated info

Any new numbers on the merc 250 repower?? Interested in getting the same setup on 05 26. Thanks!
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  #8  
Old 05-04-2020, 09:29 AM
Fishindave9 Fishindave9 is offline
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Just completed the break in 20 hrs and it seems that the 21's are the ticket.

My general load is 2 adults + 2 kids, either a full fishing load or a full beach load, full fuel. full water and plenty of ice. I do have bottom paint.

21 rev 4's equate to 3500 rpm at 32 mph +- given average seas and whether tabs are needed for a head sea

4000 rpm is 37-38
4500 = 42-43, but the fuel burn kicks in
WOT trimmed in is about 5200 at 49/50 mph
trimmed for speed with 1/2 fuel and the 4 normal riders is 56-5700 right around the 54 mph mark

light fuel load yesterday got 5700 at 55-56 mph with 4 normal riders, prob 2/3 water

Yesterday saw a 1-2 foot following sea that I had to slow way down to wait for a friend in a 20 footer carrying small kids he was trying not to beat to death, but was able to hold 25-26 mph at 3000 rpm with full tabs and easily hold on plane.
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Gulfport, MS
"Second Wind"
05 26fs
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  #9  
Old 05-04-2020, 03:54 PM
Fishindave9 Fishindave9 is offline
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fuel economy


15 gph around 25, but that is full tab staying as flat as possible

Sweet spot is right about 18 +- gph at 35 mph at = 1.94 mpg

20 gph around 37 mph = 1.85
23 gph around 40 = 1.74
30 gph around 45 = 1.5
WOT is 40 gph at 55 = 1.375


All of this is way better than my real world numbers with the 225 yamahas with 3 blade 19's SWS

On my best day I could squeak out 1.5 mpg, but with real world figures and running, I averaged 1.2-1.3 mpg

I am extremely happy with the motor change and prop change. You could throw on a 3 blade and get some more mph, but I'm interested in ride comfort.

The 4 blades and 35 mph equal a very good combination of bridging the seas and running on top to a degree.

Hole shot is bass boat ish. No more wide open and wait to jump the hill.
I can get on plane in a regular pace at 3000 rpm.
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Gulfport, MS
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05 26fs
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