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Upgrading my duo prop?


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Hi,

My apologies if I'm too quick to post or am posting in the wrong area. I have a 2008 Sunesta 224 Wide Tech with a 5.0 Mercury in it, and a duo prop set of Bravo Threes on the back. Our last boat had a five blade prop on it, and got out of the hole quick. This boat does NOT like to get out of the hole at all, and seems to save all of its performance for after it's planed out.

I'd like to know what the best (safe) upgrade would be to get out of the hole quicker, as we'll be towing every weekend for paying customers. Is it possible to put a double-five blade prop? I've heard something about WOT being a huge factor, is that true? Thanks so much!

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Your B3 drive has more grip than a conventional single prop drive. The first thing you should do is check WOT RPM's. You should run in the upper end of the recommended range for your motor. If you are 400 RPM or more under the recommended range, then a switch to a lower pitch prop is in order. This will improve your hole-shot significantly. There are both 3 blade and 4 blade B3 props available. Be prepared for sticker shock. Not cheap!

brick

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I have the same 2008 Sunesta 224 but with a 5.0 Volvo and duo prop setup.. My Volvo is rated at 270 HP.. I'm guessing your Mercruiser is similar HP as they are both the same block.. My boat gets up and goes no issues.. With full fuel and water I'm up on plane in seconds and tops out 50 + MPH on the speedo and if i remember correctly somewhere near 50 mph via gps.. Did you just get the boat or have you had it for a while? I can't speak to the performance with the Mercruiser setup but i suspect engine or drive setup issue, correct props, etc..

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OldChap, we just acquired it a couple weeks ago. I wasn't able to get to 50mph with only two of us in the boat, until I trimmed myself nearly out of the water... I'm a bit curious now if I do just have something not responding correctly. I was using a 5.7 liter Volvo before in my '06 Glastron, and it spoiled me. Out of laziness, I've yet to take the boat to the mechanic to have it's initial check-up done, so maybe that's the best step before adding 6 holes or new props to my boat.

Thanks for the message, and having the same boat, if you have any suggestions or tips, I'm open ears. I'm an experienced boater, but this boat has me back at square one [ kinda ;) ]. Thanks again!

(( Also, I'm not getting emailed when people post on this thread - I have all the email boxes checked, and I've checked my junk and spam folders. Ideas? ))

EDIT --> I just "followed" my own post, so we'll see if that works.

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Without having even checked Google yet, my guess would have been trim tabs costing much more than props, factoring in installation. I'll have to take a look.

Thank you both for the responses!

FYI I guarantee you trim tabs are less expensive than duo-props (at least if you get them in stainless, which i would)...

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I would expect top speed to be around the 50 mph mark. So your speed sounds OK, but need to know at what RPM. Your 5.0 should turn 4600 to 5000 RPM @ WOT. If you are under this range, you are over-propped, and should drop to a lower pitch propset.

Post your WOT data, including prop pitch (stamped on the props) and drive ratio ( probably a 2.2, it will be on the decal on the side of the out drive) and then we can make recommendations. Getting the correct pitch props is critical to both performance and engine life. Fix the props first, before adding trim tabs.

brick

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What pitch. I have a sunesta 254 5.0 motor with 24p props could see 55 on spedo. hole shot weak for sking but acceptable otherwise.. Put on 20p now fair hole shot. Just bought a 21 ft h2o with tower for skiing hope it works better.

Jay Smith

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After doing a lot of reading, I've decided it's time to take it to the shop. I hit only 46mph trimmed up while at the lake, and didn't pay attention to my WOT. The current suspect is spark plugs and/or a bad cylinder. This is with only two people in the boat as well. Hopefully, a tune up is all I need... I purchased this boat with only 55 hours on it.

I care very little about top end... I'd be happy with 45mph, but my hole shot needs to improve quickly, as we're about to start taking clients out for water sports trips. I'll do my best to post the current pitch and my WOT for any still interested. Thanks again for all in the responses.

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Bad plug causing a misfire or cylinder not firing would be more noticeable that what you are experiencing. You would top out at around 3000 RPM and it would be extremely sluggish and noticeable (speaking from experience on this one - bad/burned plug wire causing a cylinder to not fire).

Everyone's advice on WOT RPM is dead on. I am going to guess you are over propped by pitch or two. Was your 46MPH speed GPS or speedo?

As for trim tabs... should not be an option, should be standard. They are worth every penny.

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Your Bravo III has two positions for the trailing eccentric end bushing for the trim cylinder anchor point. Bravo I's are delivered with the bushing in the full trim in position, but Bravo III's are delivered with it in the maximum up travel position. Rotating the bushing to full in takes two 5/8" wrenches and about 2 minutes to accomplish, and provides an additional 1-1/4" downward travel when you trim full in. This extra trim-in really helps the hole shot and cost NOTHING... Set the skeg on a block of wood, then remove the aft trim cylinder anchor pin retaining nut and washer, then elevate the cylinder up about 2". You will see the white, plastic bushing, and you just need to rotate it 180 degrees to achieve an additional 1-1/4" trim in. Slide the bushing out, flip it 180, and slide it back in. Done deal.

W

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Wing, I'm very curious how this is accomplished. A mechanic does any work involving the engine or lower unit - so rotating bushings, achor points and up travel position are all greek to me.

Has anyone seen a video on how to rotate the bushing?

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Rbarbot2 just posted an excellent review of the process. Regardless of this drive position, you need to be propped correctly. First, make sure your boat is running properly. Then check your WOT RPM. Go from there. Adding trim tabs is always good, but you need to be properly propped first.

brick

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Brick is so right, but I've found the factory offerings from Chap to be pretty close relative to optimized props. Moving my bushing cured the bow rise, and tendency to porpoise, but I needed to add trim tabs before I was able to utilize the dead rise as it was intended. Now I can keep the bow planted in a chop without adding speed, which I see as a good thing. My passengers think so too. 30 is fast enough in a 2' chop on a sloppy day, especially if the seas are not uniform. Rbarbot2's post has the illustration about the bushing right out of the Merc manual. This is a VERY SIMPLE do it yourself, so jump right in and post if you get stuck. You won't, as this is truly a 2 minute deal. Just remember to lower the skeg gently on to a wood block with no pre-load before removing the trim cylinder anchor pin.

W

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If you want to keep the cash output on the low side, then I'd do the following:

1. Have the boat checked out by an experienced marine tech for proper performance. New cap and rotor would be good.

2. Have the tech place the drive in the Bravo 1 position - seriously helps for faster and flatter planing, with no harmful side effects.

3. Have the tech time the props if you're running a 3/3 blade prop set.

If you want to spend some money, or should you ever hit a shoal and need new props, than I'd get Bravo 3 XR props.

I have personally found that for the MerCruiser Bravo 3 powered Chaparral's with a hull pad such as yours, that the optimum set up is to run Bravo 3 XR props, with the drive in the Bravo 1 position. The task of recalibrating your trim senders for your square digital gauge is very easy - can be done on the tachometer.

Advantages over the standard and Elite series Bravo 3 props for Chaparral models with a hull pad are:

faster planing

better fuel economy

stronger performance in the mid range

superior holding while cornering

Chaparral knows about the XR props, and their advantages, but they do come with a heavier price tag. Come standard on models such as the 327 SSx, 277 SSx with 525 Race engine, 370 Signature with 8.2 Mag, etc.

If you're running say 24" props, and get 4900 RPM at wide open throttle, then I'd consider running the 23" XR set. 5.0L MPI can turn them, but I generally find 350 Mag is minimum - good working props, but it takes power to turn them.

NOTE: Bravo 3 XR props are cupped, and do require torque. Merc technical info states that 260 hp to 525 Race engine is the target.

How to place your drive in the Bravo 1 position.

http://forum.chaparralboats.com/index.php?showtopic=26114&hl=

Bravo3XRprops.jpg

Timed props - if you're running a 3 blade forward, and 3 blade back prop set.
Bravo3props-timed001.jpg
Bravo3props-timed002.jpg

Hull Pad (used on 224, 244, 284 Sunesta, SSi WideTech models, and several other Chaparral models)
ChaparralHullPad001.jpg
The most important things in life aren't things.
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Great info.. Want to thank you all for your info. It bothers me when people don't report back, so I'll do my best to let y'all know what's happened.

Today... was the first time my boat has taken more than 2 people, and holy cow, what an eye opener. I decided to time how long it took to plane out, and the first try, against the current (slightly windy today, but nothing my boat should struggle with) it took 24 seconds. When I went to drop off two passengers later in the day, I tried planing out again, and it took about 12 seconds. Another disappointment. I took the opportunity to check my max speed (42 today) and the RPMs were steady at just under 5500. Looked like 5400 @ 42mph (on the spedometer and GPS).

Later, with 6 people in the boat (2 on the front, 2 in the middle, 2 in the back), the boat wouldn't plane out at all.

I didn't know the problem was this bad... so instead of guessing further, it's not at the shop to be looked at this coming week. We'll be looking at compression, spark plugs, water in the gas, throttle cable, trim settings, prop timing and angle, and I'm sure some more things.

b.o.a.t. - break out another thousand.

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Great info.. Want to thank you all for your info. It bothers me when people don't report back, so I'll do my best to let y'all know what's happened.

Today... was the first time my boat has taken more than 2 people, and holy cow, what an eye opener. I decided to time how long it took to plane out, and the first try, against the current (slightly windy today, but nothing my boat should struggle with) it took 24 seconds. When I went to drop off two passengers later in the day, I tried planing out again, and it took about 12 seconds. Another disappointment. I took the opportunity to check my max speed (42 today) and the RPMs were steady at just under 5500. Looked like 5400 @ 42mph (on the spedometer and GPS).

Later, with 6 people in the boat (2 on the front, 2 in the middle, 2 in the back), the boat wouldn't plane out at all.

I didn't know the problem was this bad... so instead of guessing further, it's not at the shop to be looked at this coming week. We'll be looking at compression, spark plugs, water in the gas, throttle cable, trim settings, prop timing and angle, and I'm sure some more things.

b.o.a.t. - break out another thousand.

Yea, that thousand won't get you a pair of XR's...

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W's right again, XR's are well over that even at cost...

The audio alarm and rev limiter would have kicked in well before 5400 RPM. Probably around 5100 RPM or less. You make no mention of 2 red led lights coming on for the tachometer, or hearing an audio alarm, so I'm thinking the problem is mechanical in nature. Any odd noises coming from the engine??

If you have the drive trimmed down when planing out, and you're getting this performance, than I'd say you're down a cylinder, or something else is reducing hp output. If the compression test gives odd readings, ensure they do a leak down test as well.

I don' want to pee in your corn flakes, but if the news should come back that you need a new engine, PLEASE order a 350 Mag long block. Everything will bolt up exactly, and you'll end up with superior fuel economy and performance. I honestly don't think you'd have to reflash your ECM.

Truly don't think you need a new engine; just speaking about the worst case scenario, and what I'd do if the boat were mine.

I do know that a 224 Sunesta with MerCruiser 5.0L MPI with an Alpha 1 has way better performance than what you're reporting.

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Well the report from the mechanic both surprises and disappoints me.

I've been told, with my props (I found out they are 28 pitch) and only a 5.0 Mercuiser, I shouldn't expect a lot of performance from a boat of this size and weight. A boat this size, they said, should have a much bigger engine if you want to be able to tow while having 4+ passengers inside.

They said everything checked out, but that I was indeed overpropped, and for running a charter water sports business, a 24, 22, or if I'm VERY careful a 20 pitch would work. Trim tabs were suggested by Chaparral after they explained what I wrote above.

My decision now is to add bells and whistles to a boat that's not what I'd hoped it would be, or to find a boat that does what I want right off the showroom floor. I hate to sell a boat I just bought, but assuming a 5 liter engine was enough to accomplish great performance seems to have been a mistake... at the moment.

I have the same 2008 Sunesta 224 but with a 5.0 Volvo and duo prop setup.. My Volvo is rated at 270 HP.. I'm guessing your Mercruiser is similar HP as they are both the same block.. My boat gets up and goes no issues.. With full fuel and water I'm up on plane in seconds and tops out 50 + MPH on the speedo and if i remember correctly somewhere near 50 mph via gps.. Did you just get the boat or have you had it for a while? I can't speak to the performance with the Mercruiser setup but i suspect engine or drive setup issue, correct props, etc..

...and OldChap, if you have time please contact me. I'd love to hear what setup you have. We will most likely be adding trim tabs to the boat on Saturday, but if you are able to get 6 people up on plane quickly, then I need to get a second opinion on my setup.

Thanks everyone!

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A set of 22s and tabs will make you MUCH happier! Who the he[[ put 28s on that boat?! Way too much prop . . .

Point of comparison: I have 24s on my 220 with 350MAG; would have come with 26s if I hadn't asked for 24s (we like to ski, 'board).

If you need to pull while having several folks on board, then the 22s should do nicely I should think. Keeping your crew in the bow during take off helps a lot as well.

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My 2002 220SSi also came with 28's. It had a 5.7EFI B3 2.0 ratio. 3800 RPM@ WOT. What were they thinking?

My 2005 220SSi came with 26's, and I swapped them for 24's.

Change your props before you decide if you like the boat. I think you will be pleasantly surprised.

brick

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