272 islander 61 mph @ 5200 rpms.....(help)
 

Ok here goes,
Hey all,
I'm new here so hi!!
Last year I purchased a new to me 1997 272 Baja islander with a 496 ho (it's a 2006 model repower)
I have a few questions concerning speed.
I have only been able to achieve 61 mph full tank almost empty 4 passengers or by myself it always seems to top out at 61 mph.
From what I understand it should go maybe mid 60's some saying upper 60's
Anyway I have the seastrainer (I think that's what it's called) on the bottom of the boat for the 496 fresh water intake.
I also have a 23 pitch mercury mirage stainless prop and thru hull exhaust. (Engine is factory)
At the speed of 61 mph (GPS speed) my tach shows it spinning at 5200 rpms so I don't hold her there too long.
The engine has 500 hours on it, the hull has no scratches or gouges but the zinc plates on my outdrive are pretty corroded.
Also the prop has a slight gouge on one of the blades and I don't know what gear ratio I have.
One other thing...my trim gauge don't work I'm sure because my trim sender/limiters are shot. (I just ordered a set to replace them before I get on the water this year)
Anyways is my speeds waay off or am I about in the ballpark with where I should be?
Oh yeah this is at about 650' sea level.
At this time I cannot get a labbed prop due to me getting brand new tires on my boat trailer and going to get my boat reupholstered hopefully before June.
So????
What should I do?
Thanks

Im no expert....but I dont think you are that far off if off at all.

My 25 Outlaw...same boat with 502mag full tank me and my girl does 64-66 with either 23P 3 blade mirage plus or with my 4 blade labbed herring....I run the herring cause it lowers my cruise RPMs by about 3-400 though.

61mph with 385hp in a straight V 27ft sounds close to the mark,
you might gain 3-4 mph by going to a bigger pitch prop but you will sacrifice all around get up and go.just depends what your looking for.

Your at 19% slip. Might have it over trimmed a bit or prop might need a tune-up.

Thanks all.
Someone mentioned the 385 hp engine...that would be all fine and dandy if that's what I had b-u-t I have the 425 hp engine...
Anyway...what's the thoughts on the 25 p prop?

That's a possibility.
That's one of the reasons I'm ordering a trim sender/limit kit.

I'd say you are pretty close also, even with 425.

Try other props, doesn't matter who says what. Only way to be sure is to try other props.

I'd try the 3 blade 25P, or a 24P 4 blade.

Good luck-

Have you tried trimming it a little higher with the trailer trim button???

No I haven't....kinda scared to.

Little update;
Tried a mercury mirage plus in a 25 pitch (supposed to be labbed, just don't know any specifics on it)
My boat hated it, at top speed getting a measily 58 mph at 4600 rpm but it cruises nice about 3800 or so at 40 mph or thereabouts.
Unfortunately we could not get my outdrive off because we think the input shaft is rusted to the coupler - permanently :(
So I tried trimming it up as far as I dared got a tremendous rooster tail (sure looks impressive) but didn't make me go any faster.
I'm thinking of seeing if bblades could repair/tune up my 23 pitch because I liked that prop better.

I haven't heard of really any of these stock 496/502/454 27 ft/25 ft Bajas pulling a 25 pitch real well so I am not surprised. Get your 23 worked and you will see mid 60's on a good day, Smitty

Thank you sir,
I'm going to give Bblades a ring tomorrow
I think that's the route to go.

why are you trying to get the drive off? There should be grease fitting on the coupler maybe you can grease it and give it a little time to loosen up. don't overdo though or it will go flying everywhere.

Trying to get the drive off to replace the trim limiter/sender.

Hello,

Before you do anything you must get to the bottom of the excessive slip numbers. A 23" prop turning 5000-5200 should give you 65-67 mph. I have some ideas as to why your slip is so high. Please call to discuss. If you do not correct the problem, a prop tune up won't do much good. If we lower slip, you may need a 21" prop?

Thom

I believe the shape your current 23 is in may be the issue with the slip #. Unless you have a raised "X" dimension or if the prop has been repaired or tweaked some place incorrectly, the stock set up of your hull would not dictate a 19% slip. Unless you were over trimming the boat and you have not even tried trailer mode.
Send us the 23 and we can see where it is as far as the stock specs. We can also send you props to test where you don't have to buy anything. We only charge a $45 test fee.
Let me know if this sounds good to you. Or call and we can discuss options.

Brett

I tried calling the other day but the girl said everybody was in a meeting.
I took my prop to a local guy to get repaired.
If it still doesn't perform like I want then I will do the test props.
Thx

G, wonder why my slip #'s are so high?

We are busy with many things this time of the year and that is why I often suggest you send the prop in. It will get inspected quickly and then you will be contacted to discuss the findings. It can save time rather than discussing the prop in depth on the phone before we see it. Make sure your local guy understands the specifics on the geometry of 23 Mirage. A repair without getting to the specs. back to stock will not give you accurate knowledge.

Brett