2007 Crownline 180BR Prop Change

[soonerce]

Hello, I'm new to this forum and the world of owning a boat, but grew up on boats and love it. I recently purchased my first boat, a 2007 Crownline 180BR 18' (~2600 lbs), and after a few trips on the water I think I need to change the prop.

The current prop is SS Michigan Wheel Apollo, 14-1/8" X 19 3 blade. Trimmed out the top speed is about 40 MPH and the WOT RPM is 4100.

From what I have read the WOT RPM on the 190 HP 4.3L V6 is supposed to be between 4400-4800, and the boat takes a terribly long time to plane out when trying to pull a skier, which is not pleasing.

The sterndrive is Alpha One with 1.81 gear ratio.

Using Mercury's prop selector guide, it generally is recommending switching to a 17 pitch prop, which makes sense as it would increase my WOT RPMS.

The question I need help with is, does it makes sense to go to a 17 pitch prop and does brand really matter? I was looking at dropping $150 for a Mercury Black Max Aluminum 15x17 3 blade, but I could buy the Quicksilver Aluminum for $102, and I don't believe I need the hub kit since my current prop will already have it.

I don't think at this point Stainless is that necessary, so I don't see the need to drop $400 on a nice stainless prop...but I could also do another Apollo for $200. So many options, it makes my head spin. Can anyone give me their 2 cents?

Thanks!

 

[jkust]

Re: 2007 Crownline 180BR Prop Change

Hold on there. You've got bigger issues that a prop. a 2600lb 18 footer isn't that heavy a boat and a 19 would make it easily over rev at wot. There's just no way you would need a 17" prop on that boat. Have you verified your speed via gps? I'd estimate that the speed does match the rpms. A mid weight Crownline with a 19 and your specs would easily push over 5000 rpms overreving. Even a heavilly cupped, ss prop would allow near 5000rpms. My 3000lb 18 footer, same engine as you, with a 21", heavily cupped prop with 4 aboard and 33 gallons of gas gets 4850 rpms and will over rev with the 21" non cupped prop. With a 19 I'd blow it out the door and a 17" would just be a lot of managing the tach. Thats about 47mph gps and with low gas and two aboard almost 52on gps. You've got some serious slip happening. Take your finger off the purchase prop button.

 

[soonerce]

Re: 2007 Crownline 180BR Prop Change

I have not verified the speed with a GPS, I will try that tomorrow. I just know that it takes forever to plane out pulling a single skier and I need to correct that. What do you think my next step should be?

 

[jkust]

Re: 2007 Crownline 180BR Prop Change

I have not verified the speed with a GPS, I will try that tomorrow. I just know that it takes forever to plane out pulling a single skier and I need to correct that. What do you think my next step should be?

More questions first. With a 19" prop this question shouldn't need to be asked but it she skier doing a deep water salalom start? Do you have say 6 heavy people in the boat? No disrespect but you are sure the boat doesn't have a 3.0 liter and the 1.81? How does the boat perform with just you in it? Did you water test the boat when you bought it and if so is this how it performed? Are you in high altitude?

 

[soonerce]

Re: 2007 Crownline 180BR Prop Change

More questions first? With a 19" prop this question shouldn't need to be asked but it she skier doing a deep water salalom start? Do you have say 6 heavy people in the boat? No disrespect but you are sure the boat doesn't have a 3.0 liter and the 1.81? How does the boat perform with just you in it? Did you water test the boat when you bought it and if so is this how it performed? Are you in high altitude?

It was a deep water slalom start, but only 2 people in the boat. I'm pretty sure it is the 4.3L V6, I checked the engine serial number online and the distributor cap definitely has 6 wires coming from it. I am not in high altitude. I didn't test it on the water, just started it with muffs on. I haven't tested it with just me in it yet, I'd imagine it would gain a little more performance.

Using the slip calculator, it appears slip isn't a problem. 40 mph is the theoretical speed with 19 inch prop and 1.81 drive ratio.

I'm just not sure why I'm not acheiving the right WOT range. The boat planes very quick without a skier, and it has a hydrofoil on it, not sure how much that matters in the situation.

 

[steelespike]

Re: 2007 Crownline 180BR Prop Change

I agree with jkust. I think you may have motor issues. your speed should be around 50 and again the 19 should be over revving.
19 would normally be the choice for water sports.
Could be as simple as the throttle isn't opening all the way. Be sure its firing a on all cylinders.
Do a compression check. Probably has electronic timing but be sure it is timed right.
Is the bottom clean and smooth? Be sure to trim down for hole shot.
Just noticed the foil comment. Sometimes they can actually dig in out of the hole and they can sure steal some speed.
I would try it without the foil.

 

[soonerce]

Re: 2007 Crownline 180BR Prop Change

I agree with jkust. I think you may have motor issues. your speed should be around 50 and again the 19 should be over revving.
19 would normally be the choice for water sports.
Could be as simple as the throttle isn't opening all the way. Be sure its firing a on all cylinders.
Do a compression check. Probably has electronic timing but be sure it is timed right.
Is the bottom clean and smooth? Be sure to trim down for hole shot.
Just noticed the foil comment. Sometimes they can actually dig in out of the hole and they can sure steal some speed.
I would try it without the foil.

Thanks, I will take the foil off for tomorrow's outing.

As far as the other stuff you recommended goes, I would have to take it to a marine mechanic right? How about checking to make sure the throttle is opening up all the way, that seems like it may be easier to check.

 

[jkust]

Re: 2007 Crownline 180BR Prop Change

It was a deep water slalom start, but only 2 people in the boat. I'm pretty sure it is the 4.3L V6, I checked the engine serial number online and the distributor cap definitely has 6 wires coming from it. I am not in high altitude. I didn't test it on the water, just started it with muffs on. I haven't tested it with just me in it yet, I'd imagine it would gain a little more performance.

Using the slip calculator, it appears slip isn't a problem. 40 mph is the theoretical speed with 19 inch prop and 1.81 drive ratio.

I'm just not sure why I'm not acheiving the right WOT range. The boat planes very quick without a skier, and it has a hydrofoil on it, not sure how much that matters in the situation.

Ok. As a general rule, hydrofoils or wale tails and I/O's do not go together. Outboards yes, I/O's no. The previous owner was trying to correct some problem and didn't know enough to never put a hydrofoil on an I/O. If I were you, I'd pull the Hydrofoil off and give it a run. 40mph should be accompanied with 4800rpms with you having to ensure it doesn't over rev and I'd expect more along the lines of 43 or 44 with excellent out of the hole performance. Is your tach a Faria? Farias and some other tachometers have a switch behind them for 4 cylinder, 6 cylinder and 8 cylinder that needs to have the correct setting switched on as well.
Not that this does you any good now but a buyer in the know would never buy a boat only tested on muffs. A boat not under load can hide all kinds of issues. Not that this matters but since the boat is so new, how many hours are on the hour meter? How does the engine run in other slower situations...any symptoms?
Any boater should own and carry a spare prop, prop wrench, prop lube and an extra hub kit. I'd pick up all of that up and give it another whirl as welll. It isn't uncommon to have a 21" and a 19" where you both have a prop for the boating you intend to do and a spare if you hit ground.

 

[soonerce]

Re: 2007 Crownline 180BR Prop Change

Ok. As a general rule, hydrofoils or wale tails and I/O's do not go together. Outboards yes, I/O's no. The previous owner was trying to correct some problem and didn't know enough to never put a hydrofoil on an I/O. If I were you, I'd pull the Hydrofoil off and give it a run. 40mph should be accompanied with 4800rpms with you having to ensure it doesn't over rev and I'd expect more along the lines of 43 or 44 with excellent out of the hole performance. Is your tach a Faria? Farias and some other tachometers have a switch behind them for 4 cylinder, 6 cylinder and 8 cylinder that needs to have the correct setting switched on as well.
Not that this does you any good now but a buyer in the know would never buy a boat only tested on muffs. A boat not under load can hide all kinds of issues. Not that this matters but since the boat is so new, how many hours are on the hour meter? How does the engine run in other slower situations...any symptoms?
Any boater should own and carry a spare prop, prop wrench, prop lube and an extra hub kit. I'd pick up all of that up and give it another whirl as welll. It isn't uncommon to have a 21" and a 19" where you both have a prop for the boating you intend to do and a spare if you hit ground.

I will check the tach manufacturer. Yeah, I knew I was taking a chance buying it without taking it out on the water, but I had already had 3 boats this summer sold just before I was able to even look at them and I didn't want to risk letting this one go too.

The boat as 162 hours on the meter give or take a few tenths. The engine seems to run beautifully, it sounds great - I'd imagine that most people would never second guess it, I just really like to learn a lot about the toys I purchase. The guy I bought it from probably had no idea about WOT RPM range. I would like to pick up another prop like you suggest, I definitely need to figure out what the problem is before I buy another.

The boat also has an aftermarket swim platform from swimplatforms.com - It doesn't seem like this drags too terribly bad, but it might be hurting the hole shot by dragging the water when the boat's nose is high in the air?

 

[jestor68]

Re: 2007 Crownline 180BR Prop Change

I suggest you just put a 17" prop on it and get your boat going. That prop will produce good acceleration and get your rpm up to about 4500 at full throttle, while producing the same or slightly higher top speed.

The right hydrofoil works as well on the I/O as it does on the outboard motor. The Doel Fin on my Mercruiser planes the boat in half the time, compared to without. This same Doel Fin was used on the previous boat with a Mercury outboard.

 

[jkust]

Re: 2007 Crownline 180BR Prop Change

Lots of stuff going on. Just poke your head under the dash at the back of the tack and look for the toggle switch. That'd be a long shot for a boat that performs fine but the tach doesn't match. Have seen it a handful of times over the years even on new boats. Even if you have a pretty old boat where I've seen hydrofoils used and are exceptions to the general consensus on foils, there is just no way that new hull requires a foil. Likely they were trying to correct porpoising or possibly excessive bowrise where trim tabs are the usual fix but I'm just guessing. Tabs require some planning and drilling into the glass and a hydrofoil obviously doesn't. They tend to rob performance. As for the swim platform, I'm going to say it's not the problem given it was an option a person could have selected from the dealer and presume the aftermarket version is identical and installed correctly but again all conjecture.
First step, pull the foil off and test it then figure out if you are getting full throttle when at WOT and the different behavior of the hull. Slapping on a 17 is just masking the symptoms but since I don't know where you are, you may be like me here in MN where the season is going to over very sool and you just want to get out there. By chance to you have the 5extended warranty on the engine which I believe was transferable?

 

[soonerce]

Re: 2007 Crownline 180BR Prop Change

Fortunately I live in Oklahoma (well semi-fortunate, the heat is oppressive), where the boating season goes all the way to October so I have plenty of time.

As far as the 5 year warranty, I have no paperwork for it, so I'm going to guess it doesn't apply. Does it count from the date of sale or manufacture? Since the boat is 2007 then the 5 year would be up or close to being up. Or do boats sell a lot later? I'm thinking of it like a car which may not be the case.

I'll update tomorrow night after a day without the hydrofoil. It's a monster foil, Sting Ray XRIII. I've never seen one so big, but then again it's been about 15 years since I was in the boating world. Hopefully the tach is set wrong!

 

[jestor68]

Re: 2007 Crownline 180BR Prop Change

I tested a Stingray foils and found that they caused considerable drag at speed. It felt as if I was towing a skier. It is likely that removing that monster will let your motor rev up higher. Whether it will get up to the proper(4400-4800) rpm range remains to be seen.

Of all the (several) hydrofoils that I have tested, only the Doel Fin worked as advertised. I found that it's lift/drag factor was good to about 40 mph; after that the drag took effect and caused a slight loss of speed. In the cruising speed ranges, it actually helped to increase speed slightly.

The warranty starts on the date of sale to the original buyer. Some warranties are transferable; some are not.

 

[soonerce]

Re: 2007 Crownline 180BR Prop Change

Well, it turns out that the hydrofoil isn't the issue. I imagine that whoever put it on was trying to fix the performance problem. Today I did have a bigger load than normal, 5 people total, but the boat wouldn't plane out at all unless I had 3 people move to the bow. It wouldn't plane with 2. I clocked it at 40 MPH on the GPS at around 4200 RPM though, which I think is pretty close to right on. The boat just seems so sluggish when getting up to speed. Something is off.

I guess the next step is to take it to a marine mechanic. It needs to go anyway because my son turned the ignition all the way around while the boat was on and now it's anybody's guess as to where the key needs to turn to start the boat. Also the temp gauge isn't working. Good thing being on the water is so worth it!

 

[jkust]

Re: 2007 Crownline 180BR Prop Change

I'd still pick up another prop as well. Your engine requires a 200 hour tune up so possibly time to have that done as well. Keep us posted but my bet is it is a simple issue.

 

[soonerce]

Re: 2007 Crownline 180BR Prop Change

So it turns out that as everyone thought, it wasn't the prop. I replaced all of the plugs in the boat with the recommended AC Delco MR34LTS and took it out yesterday. WOT RPM's are now 4800, right where I wanted them to be, at the top of the spectrum. The old spark plugs were pretty fouled, and the gaps weren't set correctly on all of them. They also weren't the recommended plugs from the manual.

One of the plugs was set with such a small gap that it was almost touching the element...so it might not have been firing at all.

So glad that it was only $18 to get the WOT RPM's where they need to be.

 

[Maclin]

Re: 2007 Crownline 180BR Prop Change

Good deal! Regarding spark plugs, when the gap is closed, like a short, that can steal current from the spark cycle and affect all the other spark events.