Props for 265 with 225 4 strokes

[Boat Hound]

Was reading these posts with interest, as I am switching to 4 blade props 14 5/8x17 REV 4's recommend by Ken. There is quite a bit of size difference in what has been tried here, guess will see how it works out. My boat [265] has f225s on it. Sounds like most of these test were over propped, so hoping these will be spot on.

I am very interested in the results. Please post when you get a chance. I have the exact same setup as you, and had been messing with props all of last season. Was about to bite the bullet with the Rev 4's, just ran out of warm weather. I tried the 17" Offshores, which were certainly not the right prop.

 

[Bill_N]

Was reading these posts with interest, as I am switching to 4 blade props 14 5/8x17 REV 4's recommend by Ken. There is quite a bit of size difference in what has been tried here, guess will see how it works out. My boat [265] has f225s on it. Sounds like most of these test were over propped, so hoping these will be spot on.

I bought my Mirage 18's from Ken and had him send me a set of the Rev 4 17's. Unfortunately the ones he sent were both RH and I never got to run them. The Mirage 18's are close to perfect for a 3 blade prop if you have F225's. The first year I ran them economy was up but I wasn't getting full rpm's out of them. Last spring I did all my filters and plugs and then had the port engine set-up again as it was stumbling occasionally at idle. Since then I've been able to turn 6000 rpm with about 200 gallons of fuel and just myself in the boat. These props will only cavitate if it's really rough.

Looking at the Mirage 18's and the Rev 4 17's side by side the Rev 4's seem to have quite a bit more surface area so you may be over-propped with them. Make sure you post your results when you run them.

 

[duconce]

I will post as soon as I get a chance to run them, looks like it might be a couple of weeks before I have everything back together. A few repairs were needed that I hadn't counted on. The whirlpool begins.

 

[Boat Hound]

with gas prices looking like they are going, news on the most efficient props will be eagerly awaited !

 

[Bill_N]

The Rev 4s might run better that the Mirages but I doubt they'll be more efficient. Ken will tell you that as well. The Rev 4s should give you a better holeshot, lower planing speed and maneuverabilty when docking.

 

[duconce]

Well I finally got my boat in the water in San Francisco bay, haven't driven the boat so was mostly getting the feel for it. Went out the gate up to Stinson and back. It's been about 12 yrs since I had a boat this size, I was learning as I went. I was running the four blade props, never got drive it with 3 blades. With just one afternoon I can only give first impressions. The four blades bring the boat strait out on plane very quickly, my boat was full of fuel and the engines mounted all the way down [ thats the way I got it], it has bottom paint. I didn't get a to write anything down, the one number I cruised at 4300 rpm= 30knots and gauges showed a burn rate of 18.4 gph. I didn't run wide open, will try that next time out. I will say around the dock the boat was very easy to maneuver .The boat is pretty sensitive to trim tabs and coming off plane. All in all I am very pleased with the boat. I will spend sometime writing down some numbers when I get some more time on the boat, but I really like the way the four blades have performed so far.

 

[Boat Hound]

Is my math right on this? That is ~1.9 mpg??!?
30kts = 34.5mph/18.4gph = 1.87mpg
Crap that is what the Yamaha performance report gives, albeit, at a lower speed. I would say if those numbers are accurate, that is indeed the prop for that boat. Lightly loaded the best I see is 1.5mpg, with 17"SWSII. That is like a 20% improvement.

Granted there are not too many days I can run that fast Offshore, but the run to then end of the river would be much more economical.

 

[duconce]

I should have mentioned that conditions were extremely calm and no wind, on a short run last weekend with wind and more normal conditions, I showed 19.5 to 19.8 gph at 4400 rpm to 29.5 knots, at 3800 I was running 24kts and show 15.5 to 16.1gph. These are under much more normal and rough conditions. So I would think this would be a better idea what one would expect. Still very pleased with the boat operates with these props, I don't really use any trim tab adjustment, as motor adjustment seems best. Again my motors are all the way down [bolts at top mounting hole].