265Express owners - prop tweaking for better MPG's

[Boat Hound]

Picked up a new to me 04 265Express with the F225's and was thinking about futzing with the setup for better fuel economy. Right now I believe I have the standard set up (SS 17" I believe) and am getting ~19gph @ 4000 rpm's and around 32 MPH- I have obviously figured out this varies a lot depending on fuel load - those 250gallons sure do weigh a lot!

Has anyone already been through this exercise and what have you found? I am not real unhappy with this - but I just can't help but try.

 

[jekyl]

I believe you will find lots on this if you do a search. 17" mirage merc props are highly regarded. As you say load and conditions make a big difference.
I believe best reported economy is around 1.8 mpg and around 3,900 rpm.
I rarely see those numbers unless I am very lightly loaded.
I have 4 blade Solas in a 17" pitch with a 14 1/2 diam.

 

[Boat Hound]

I am curious - how have you found the 4 blade props worked out for you as far as the engines ventilating? I have found in certain conditions, the props do break free pretty frequently.

 

[jekyl]

Whilst they are possibly not the most economical props. I run them one hole off the highest position and regularly at 3 -4 bars trim with no ventilation or cavitation.

I would like to try some 17 Mirages but they are very expensive here......around $1500 each so will wait for some to come up on THT.

 

[gradyfish22]

There were 2 guys on here last year who played with props, at first the numbers sounded promising, but after looking at my numbers they were only slightly better and would be hard top justify spending the money ti repower. I played around with the idea of doing so anyways this spring but put it off, I had a few offers from prop shops who claim they can do better then what I'm getting, if they honor there offer to keep giving me props til we find the right one I still might bite, I want better cruise economy and higher cruise speed otherwise its not worth spending the money. I know guys said merc props have been doing a little better, also going with a good quality custom prop will help, you get a better prop blade and more surface area typically which makes them run better, but the problem is finding the right diameter and pitch for each brand and style to make it a better match. Hopefully I find the right prop next year, it would be nice to increase my range since its 100nm to the canyon for me and I make the trip a few times a season.

 

[CKJR]

Hi, I did some messing around with props, First what does your rig turn wide open, you want to see 6000 rpms. My sailfish with f225's had yammie 19"s which only maxed out at 5400-5500, tried the 17, 3 blade yammies, got the rpms but didnt like the mid range bite especially in rougher seas, I tried the merc 4 blade 17" props (found on ebay) and i feel these are the best match for my rig, i get 6000 max rpms, top out at 45mph with 1/2 load, my fuel burn rate is 1.5 to 1.72mpgs gps from 3800 to 4400 rpms depending on sea and use of tabs, but what i like is that if i have to dial down to 3200 to 3600, the props hold and do not cavitate.

 

[gw204]

Buy your props on Ebay and if they aren't right, sell 'em on THT. You can actually make money... I've done it twice.

 

[Boat Hound]

I think I am going to try the 4blade 17" props, and maybe a set of 19" 3 blades. I am getting all of the 6000 rpm's (can actually get over 6100 if I don't watch it with a light load). The main issue I have with the current set up is ventilation in rougher waters, and would like to see better fuel economy.

I just need to find a place that will let me play with them!

 

[gradyfish22]

I would stick with 17" blades, you will likely not like 19" you will likely get worse fuel economy and a little less speed, its a lot of prop for that boat and isnt needed really, finding the right 17" blade would be the best option. If your venting too much maybe adjust the mounting height lower a notch if its a problem for you, might decrease efficiency but its cheaper and could solve the problem. Also a custom prop will grip better then an engine brand prop anyday, they typically have more blade surface and a better blade shape, the merc mirages are the best out of the engine manufacturer props but still not as good as a custom prop will be.

 

[Boat Hound]

When you say - stick with the 17" - do you mean the 4 blade? And a custom prop, I assume you mean take my prop in to have it worked? I would imagine they have to start somewhere.

 

[ocnslr]

If you can make top RPM at WOT with 17" 3-blade, but are having ventilation issues, then I strongly recommend you try the PowerTech OFS4 props and stay with the 17" pitch.

You may drop a little off the 6000RPM point, but you should still be close to it and my personal experience with the OFS4 props is that they bite and hold on tight.

Try to find a local prop shop that will work with you on trying them, with the understanding that you can return if not right, and not damaged. If no local shop available, let me know and I'll see if my preferred shop here will ship to you - he already supports experimentation to find the right props.

Brian

 

[Bill_N]

I have a set of Mercury Mirage Plus 18's on my 265 with F225's. I average around 1.7 mpg with these props and a couple other guys plus gear. On the way back from Niantic last week I had it running at 6000 rpm with both engines and 46 mph for a mile or so. This was by myself and about 190 gals of fuel so I don't think it's overpropped.

I also have a set of Mirage Plus 17's and the economy is roughly the same but I lose 3 mph at normal cruise settings. Both sets rarely cavitate.
I think 19's would be too much prop. A set of Rev 4's would be nice to try as you might be able to cruise at a lower speed and hole shot would be better.

Bill