Re: top speeds at wot. what are people getting for max speed?
 

don't know my top speed, always have the family in the boat and haven't had it out with smooth water either. I'm on lanier in GA. BUT... I have a 20" 3 blade aluminum on my 99 Shabah 202 5.7 and it feels a little sluggish on holeshot especially when yanking a tube up to speed. Pulling or not it probably takes 4.5-5 sec to get on plane. It has good response once on plane. I figured it should jump a little better than it does but I could be wrong. I'd just describe it as slightly sluggish. No idea what rpms I'm turning as I'm waiting till winter to pull the gauge out and send it in for repairs. From what I'm reading I should probably have a 19 pitch on there for better holeshots, yes?

Re: top speeds at wot. what are people getting for max speed?
 

I would go with a 19 ss 4 blade. Will have a really good hole shot.

Re: top speeds at wot. what are people getting for max speed?
 

97 Z255 Shabah, 7.4L, bravo III outdrive, 26 pitch props running around 5000RPM and it doesn't matter the load or water conditions, she always does 49/50 on GPS. 3/4 throttle at 4800 is the same speed as WOT. So I very rarely open it up past 3/4, b/c it is only wasting fuel. I will say that she will go from 0-plane in about 1.5 seconds. I've never seen a 25ft boat plane out so fast. I'm attributing that to the Bravo 3 outdrive. I checked the mercruiser sight and used their prop selector and they said for performance to use 4 blade 28 pitch props and top speed should be 60mph. I'm not sure if their calculator is very accurate, I've never gained 10 mph by changing up 2p on props. I am thinking of dropping the grand to give it a try. It's always good to have a spare set of props I guess.

Re: top speeds at wot. what are people getting for max speed?
 

You'll never see 10 mph from a 2 deg pitch increase. Not to mention , the 4 blades are not made for topend. They are for torque.
But it would be interesting to see the diff.
There are quite of few members that can give you a lot of info on the B3 prop results.
I'm sure they will be chiming in soon Eric.:wink_thumbup:

Re: top speeds at wot. what are people getting for max speed?
 

Rule of thumb for me when putting new props on outboards was for every inch of pitch up was 200-300 RPM down. For example, I had a 13 pitch prop on my fishing boat and it was running 6000 RPM, redline was 5500. I went to a 14 pitch and it dropped to 5800, gained 2 mph top end. I then changed to a 15 pitch, dropped another 200 rpm and gained 2 more mph. My outboard at WOT runs at about 5600 rpm. Then a gear chipped in the lower unit and destroyed the rest of the gears so i replaced the lower and the mechanic ordered a different gear ratio. Not really sure why. But now my outboard runs 5000 rpm wot and is sluggish out of the hole. Time to drop back on the pitch.

Re: top speeds at wot. what are people getting for max speed?
 

I have a 1996 18' Shabah with a 4.3 and a 13.75/21 Alu. prop and with full fuel and my wife and I it will go 53 GPS but very slow to plane, I have a new 13.75 / 19 I will install Friday plus a Hydrofoil, hope to be able to plane at 20.

Re: top speeds at wot. what are people getting for max speed?
 

If you install a damm hydrofoil on a Mariah you will be disowned here! You might as well wear a pair of Mickey Mouse ears while you are driving the boat around too. :shakehead:

Install a pair of Smart Tabs with 60lb actuators at a cost of $125 or less and do the job right! :wink_thumbup:

Re: top speeds at wot. what are people getting for max speed?
 

Eric, why would you run at 6000 when the engine is redlined (for a reason) at 5500? Not only are you using extra fuel you are over-stressing your engine & drive line. At 6k you were way out of your efficient operating range and it wasn't surprising that your performance improved when you changed your props and got your rpms down. Just note that "rule of thumb' is standard practice. Same prop, same number of blades, increase or decrease pitch by 1" will result in a 2-300 rpm change.

As for your outboard gear change, possibly it was the only gearset available to your mechanic at the time and you are right, its time to change props again...

Re: top speeds at wot. what are people getting for max speed?
 

I never ran it at 6000 rpm. It would hit 6000. BTW, it was another outboard mechanic who told me to run the original prop that would turn 6000. Needless to say I don't use him anymore. I always ran it just below the max recommended redline of 5500. That is why I changed the props. I wasn't faulting the mechanic. He actually saved me quite a bit of money and got me a 3 year warranty. I just have to re-prop again. Which is fine since i now have about 5 props for the boat.
I was just poking around the prop section of the forum which also has some great information. Man, I love this site!!!

Re: top speeds at wot. what are people getting for max speed?
 

After checking Mercruisers prop calculator I decided to bite the bullet and try some 28p props. I'm not expecting the 10mph gain that the calculator said they would give. But we will see. I found a good deal on the props on ebay. I went with the 3 blades. I will post again and let you know how they work out. I also re-read my old post and it seems like 5000 Rpm's that I said before was high, I don't think it actually was 5000. I think redline is like 4500-4600, please correct me if I am wrong. I will recheck that also before I change the props. I will also check the time it takes to plane off now and let you know the difference with the 28p props.
Does anyone know how to check for the gear ratio on the lower unit? I know there is like 3 different gear ratios that mercruiser is showing for the BravoIII outdrive.

Re: top speeds at wot. what are people getting for max speed?
 

Got the serial number on the drive Eric?
It'll be bad to the bone for top end , if you can wind her up that far.
Holeshots' gunna sux I bet.:shakehead:
Hope you don't want to pull anything.
You really need to stay in the "powerband" , for the 7.4 that you have.
You're gonna burn fuel like no tomarrow!

JMO :)

Re: top speeds at wot. what are people getting for max speed?
 

Where is the serial number located on the outdrive? I checked the lower today and could't find the serial#'s. I didn't look to awfully hard though.
Right now with the 26p props that thing shoots out of the hole and on plane like a rocket, I'm know I will lose that but I'm hoping it won't be that bad. I don't pull anything right now with it. My buddy has a nautique wakeboard boat that we use for watersports so I'm not too concerned with pulling. If my son wants to get into that stuff I will swap the props back.

Re: top speeds at wot. what are people getting for max speed?
 

26P props and you are a rocket...I could only wish.

Upper drive, decal for the numbers.
There should be another plate on the top intake cover that has all the serial numbers on it.

I can hit 48-50 MPH with a 3 blade 19p stainless, 2 people plus a fat hairy dog on a flat water scenario.
225 Davanti with a 350 alpha one.

Re: top speeds at wot. what are people getting for max speed?
 

It should be stamped on the port side of upper of out drive,

Re: top speeds at wot. what are people getting for max speed?
 

The last bravo III I checked the gear ratio was on the starboard side of the leg.
I'm running a 1.62 Alpha One that used to have a 2bbl 4.3 V6 in front of it in my 98 Shabah 202. The 4.3 V6 would hit about 48-50 (about 4800rpm) with a 19p 4 blade stainless and get up on plane nice and quick.
I'm now running a fresh rebuilt MPI 5.7 and the only thing it's done is decreased my time to plane and increased rev-ability by about 200rpm. I've only run it with an aluminum 19p 4 blade (50mph@5000rpm) and a 23p 3 blade AL (54 mph @4600 and sluggish to plane)
My stainless 19 is at the prop shop, picking that up this week to give it a shot.
I honestly expected a lot more performance increase from the 190hp v6 up to the 300hp v8...I don't know why I barely gained a couple MPH. I can say that the v6 had about as much trouble turning a 21p 3 blade as this does turning the 23, so there is SOME performance gain, I couldn't rev past 4600 with either motor running respective props.

Re: top speeds at wot. what are people getting for max speed?
 

I can't believe you gained 110hp and mpi and only gained a few miles an hour. I'm wondering if your alpha drive is what is limiting you on the top end. I've seen other 20ft boats run 60-65 with a 5.7mpi anf bravo I combo. But then again I've found the mariah hull design isn't made to be overly speedy on top end but they ride like cadillacs! I was at a party at a sandbar on Saturday with the Z255 and when I left I past 3 boats and was jumping over 4ft rollers and it was like landing on a pile of pillows. Very smooth. I'd say 95% or more of the boat was out of the water. I did check my RPMs and they would hit 5000 so I had to back it off to about 4500. I'm hoping the 28p props help out with that.

Re: top speeds at wot. what are people getting for max speed?
 

A 5.7L with 300hp? Just to make sure we're all on the same page here, is it the 350 Mag MPI version? Because the fuel injected 5.7L is EFI, and is only 260hp.

The standard equation I've always heard the high performance racing guys say is that once you get above 40 it takes about 10hp for every 1MPH gain.

Re: top speeds at wot. what are people getting for max speed?
 

The motor is a horizon 5.7L mpi, 330 crank hp, 300 at the prop. Fresh rebuild with good compression new plugs running 92 and then 89 octane to see if there was any difference. Gonna pull the plugs this week and see how it's burning. I honestly expected about 60mph from this setup and I'm a little disappointed...
Now, I've seen this same motor in larger boats running the same gear ratio and getting 60s, I've seen it with 1.5 gear ratio running similar speeds.

Re: top speeds at wot. what are people getting for max speed?
 

Well I got the new 28p props on the Z255. The boat now runs WOT at 4600 rpm and 52mph. Before it would go 50 mph at 5000rpm. There is really no noticeable loss on take off. It still launches like a rocket out of the hole. The speed was on a gps with 3 people and a full tank of gas. I'm pretty happy with it now that the RPMs are back down to a safe range.

Re: top speeds at wot. what are people getting for max speed?
 

So what, I have made it 75 years and 12 ski rigs long before MARIAH was ever thought of.

Re: top speeds at wot. what are people getting for max speed?
 

Good for you!:shakehead::shakehead:

Re: top speeds at wot. what are people getting for max speed?
 

tha t was fubnny ....worth the effort

Re: top speeds at wot. what are people getting for max speed?
 

190 Shabah with 4.3LX 4brl and 21P SS prop...48mph GPS @ 4950rpm. Three kids, minimal gear, 1/2 tank of gas.

Re: top speeds at wot. what are people getting for max speed?
 

Eric

I think the 4 blade B3 prop is known as a XR. They have a very different pitch cup and radius to them. The ones that I have seen are only the leading prop, the rear prop is still a 3 blade, but it too has a very distinct look to it.

Re: top speeds at wot. what are people getting for max speed?
 

My 220 Talari with 7.4 bravo III I had 70mph with GPS, 2 people in boat and half tank of gas. 1 day I got the boat in the water a Mach 1 met me out by the bouy's in our cove and asked if I wanted to run him. Looked and my better half and said she go for it. I knew all he had was a 302. Smoked him bad.

Re: top speeds at wot. what are people getting for max speed?
 

New owner of a 96 Z210 Shabah w/350 EFI (Captains Choice) as of last week.. First trip out with one other person and a full tank of gas I was 50-52 on GPS at 4500 ... Not sure of prop size, just it is a 3 Blade...

Re: top speeds at wot. what are people getting for max speed?
 

95 Davanti 5.0 Liter (litre?) with 18 pitch 4 blade is 42 MPH GPS @ 4700. 19 Pitch 3 blade was 43 MPH GPS at 4800 RPM. 20 pitch 4 blade was 44 MPH at 4400 RPM. All were around 3/4 tank of fuel with my fat ass and my wife in the boat, trimmed out on a fairly smooth river. I like the combination of torque and speed with the 18p 4 blade the best, so that is what I ran for most of the summer.

Re: top speeds at wot. what are people getting for max speed?
 

Best I ever got on my 95 Talari 180 with 4.3L (160hp) was 49mph at 4950 rpm on a cool spring afternoon with just me in the boat. 19 x 14.25 Stilletto Prop.

I get around 45 now and I attribute that to the smart tabs and my rebuilt skeg is a little heftier.

Re: top speeds at wot. what are people getting for max speed?
 

This summer ran a best of 64.3 Mph Garmin GPS.

Re: top speeds at wot. what are people getting for max speed?
 

'99 Shabah 212Z , 5.7 with 19 prop, full tank of gas and 3 adults plus regular junk. Light chop, 46 mph. Might have squeezed a bit more out of her, but I couldn't avoid the distraction pounding on my shoulder and screaming at me. Maybe next trip if we can get a bit of decent weather before it closes in for good.

Re: top speeds at wot. what are people getting for max speed?
 

That sure is a purdy motor!

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Re: top speeds at wot. what are people getting for max speed?
 

Newbie here. Just bought a 2000 Z260 with sea trial tomorrow. It has the 8.1 liter 375 HP with the Bravo III. I don't know prop specs. Anybody have a SWAG for what this rascal will do at WOT?

That Z260 is obviously heavy, but with that big block, it oughta scoot, right?

Re: top speeds at wot. what are people getting for max speed?
 

97 Z222 full fuel and 4 passengers with gear 53 GPS WOT on calm water 51 later in the day with moderate chop. 5.7 LX/EFI Bravo III 26P not sure the HP on this motor I've done searches and the consensus looks to be around 250 dependong on where I look.

Re: top speeds at wot. what are people getting for max speed?
 

I have the Z280 with the smaller 7.4MPI at 310hp. It runs less than 40MPH @ WOT. I would think you will be in the mid to high 40's with that set up.

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Re: top speeds at wot. what are people getting for max speed?
 

Well I finally have enough information to add to this thread. Today was yay third trip to lake with my 1995 Talari 180 with 4.3LX. First time alone so I could focus on the boat. Full 30 gallons in the tank and only me on board (250 lbs). One six pack cooler full. Lake was fairly calm with 10 mph wind. Bimini top up.
It really ran smooth with new fuel pump and filter. Set my gps speedometer.

At WOT tach was pushing 5 g’s. GPS read 49 mph. Speedo on boat read 53 mph. That was against the wind. Did another run but kept tach at 4500. GPS at 45 mph.

I like to cruise at 30 or so but the sweet spot seems to be 40 mph. The motor and boat really feel at home at that speed.