26.5 Grady White Express performance

kman

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Running a 26.5 Express and I have a performance question. It seem like I have lost some power and I'm not getting the #s I used to. I have twin 225s F225TXR 4S. At 4000 rpms, I am cruising at 25mph with a burn rate of 1.5 gph. The best burn rate I can usually get is 1.5 - 1.6, but it's usually 1.4 - 1.5 in calm seas. Props are 15.25 x 19” Stainless Steel. I should go down to 17", but I still think I should be getting more then I am. The mph reading is off of my GPS, so it should be accurate. Just did a tune up for the spring. Any thoughts on whether this is average performance #s or if I should be getting more? Thanks for the feedback.
 

max366

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I have a 2004 265 with twin 225s. When I got it 2 years ago, it had 19 pitch props and wouldn't rev all the way up. I also noticed the Yamaha/Grady performance test used 17 pitch. I changed them to 17 pitch and the performance change was dramatic. The boat is still laid up but I recall 4000 RPM was about 30 mph, cruise at 3700 RPM or so at 27 mph and close to 2 mpg. One issue is the Yamaha fuel consumption totalizer is way off- verified by multiple empty/fill cycles. At first I thought I was only getting 1.5 -1.7 mpg or so, but once it's corrected for the error in the totalizer, it turns out to be closer to 2 mpg. More data in few weeks when it's launched.
 

Lucky13

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max366 said:
I have a 2004 265 with twin 225s. When I got it 2 years ago, it had 19 pitch props and wouldn't rev all the way up. I also noticed the Yamaha/Grady performance test used 17 pitch. I changed them to 17 pitch and the performance change was dramatic. The boat is still laid up but I recall 4000 RPM was about 30 mph, cruise at 3700 RPM or so at 27 mph and close to 2 mpg. One issue is the Yamaha fuel consumption totalizer is way off- verified by multiple empty/fill cycles. At first I thought I was only getting 1.5 -1.7 mpg or so, but once it's corrected for the error in the totalizer, it turns out to be closer to 2 mpg. More data in few weeks when it's launched.


Also just got a new 265 with 225 4's and I am wondering what your top end speed is. I think I should be getting a higher top speed than I am. Based off the GPS only i am maxing out at around 40Kts? and that is not loaded for fishing just full of fuel.
The prop may be wrong but not sure? I also think the engines are mounted a little low but not sure.

The previous owner disconected the fuel gage and installed a new one. the fuel mangmt still works to tell me flow but MPH no longer works for some reason.
 

kman

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Max366,
was this with the 17" props: 4000 RPM was about 30 mph, cruise at 3700 RPM or so at 27 mph and close to 2 mpg.?

Thanks for the feedback.
 

max366

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Kman- the stated info was with the 17 pitch props. I'm doing this from notes and memory- will confirm soon. With the 19 pitch props, I found the fuel economy was worse by about 10% and it would not hit 5500 RPM.
Lucky- my top end is close to 50 mph (43 knots) with the 17 pitch props and 1/2 tank of gas, no curtains, and just me in the boat.

Keep in mind that Grady modified the hull design slightly (I think around 2003, but not 100% sure) to reduce the deadrise, so my boat with less deadrise might perform slightly better on fuel than one with the deeper deadrise.
 

drbatts

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I have an 02 with F225's. I cruise at or around 28-30mph usually at 4300-4500 rpm. This will give me on averge about 1.5-1.7mpg. These are averages based on memory and my yamaha gauges in good conditions. Obviously conditions i.e wind and tide will change things I will top out at around 43mph at 6300 rpm. This is with full enclosure, bottom paint, and about half fuel.
 

Lucky13

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ok so I had one other guy on the boat with me almost a full tank of gas. no water in the fresh water tank. Full enclosure and I have bottom paint. I was hitting 6100 rpm and 38-39 kts according to my GPS. For those with the 225 4 stroke set up are these numbers where they should be?

my hull is a 2001 so there may be some slight differences. like you mentioned.

I also thought my engines might be mounted too low on the transom when they re powered with the 225's seams like i have a hard time getting the bow up. even at full throttle with engines trimmed it seams to dig a bit???
 

Grog

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Where's the cavatation plate when you're properly trimmed up on plane?
 

Lucky13

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if i am trimmed all the way up the plate is still not out of the water it is in and out of the water. I would think that trimmed all the way up the plate should be out of the water.
 

drbatts

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Lucky13 said:
ok so I had one other guy on the boat with me almost a full tank of gas. no water in the fresh water tank. Full enclosure and I have bottom paint. I was hitting 6100 rpm and 38-39 kts according to my GPS. For those with the 225 4 stroke set up are these numbers where they should be?

my hull is a 2001 so there may be some slight differences. like you mentioned.

I also thought my engines might be mounted too low on the transom when they re powered with the 225's seams like i have a hard time getting the bow up. even at full throttle with engines trimmed it seams to dig a bit???

Top end numbers on my 02 with f225's are similar.
 

Lucky13

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I have had a chance to run the boat several more times now and it seems to be getting the right rev. My top end numbers seam ok considering full enclosure and all other factors. The one think I keep noticing and would love some feedback on is the bow lowering at top speed.

So when cruising engines trimmed up and running great the bow is out of the water very nice.


when I drop the throttles and open it up the bow absolutely lowers and digs in more. I have never had a boat that did that. It could be because of the hull design and the dead rise as the hull is an 2001 but I am not sure. Have any other 265 owners experienced the same thing. Sorry I do not have a pic of the boat at full speed.


Thanks
 

Curmudgeon

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if i am trimmed all the way up the plate is still not out of the water it is in and out of the water.

Performance is usually optimum when motor is positioned where the plates are skimming the surface of the water or very slight above when on solid plane and in smooth water. With that said, that's the point you can begin to play with the props to change performance numbers. Trim will not affect the cav plate to any appreciable degree, unless you're over-trimmed, and then the plate may be in and out as the boat does a slow porpoise ... :wink: