posted 09-02-2005 11:14 PM ET (US)        

I just had mine raised to the top hole (BW didn't do it right) and I should be going higher, but BW screwed it up.

I am still turning the same wheels (17P Rev 4's) and my top speed has gone from 46 to 50. Fuel burn has gone down 4 gph.

The boat also runs much better with more stern lift and more ventilation for the props at the higher height. Not even completely trimmed out I got 6000-6100 RPM a motor.

Check your motor heights. This boat is possibly a 55 mph boat with Optimax XS mounted at the correct height, propped right, and no bottom paint or obstructions. a 275 Verado/320 Outrage owner claims 52 w/o bottom paint. I don't know if his motors are at the correct height but manufacturers are mounting the Verados too low - and in this case, mine too.

They are still too low.

Boat is quicker than I thought it was and she really likes to run. She rides better going 50 in 1-2 than 28 mph.

I would be probably to 53 mph and maybe more if I moved them up more and turned 19 Mirage props...I'm disappointed I can't.

posted 09-03-2005 08:43 PM ET (US)            

Just thinking aloud here but one reason I can think of for mounting the motors lower is that you've got pressurized straight six engines that have their top most cylinder most likely farther away from the water pump than any other motors of comparible HP. I would be concerned that by raising the motor and lowering the water pressure from the pump, the top cylinder might not be getting enough water for cooling purposes if the pressure drops off too much. I think its worth a call to Whaler to discuss. In any event, keep an eye on the water pressure and cylinder temp.

posted 09-05-2005 07:42 PM ET (US)            

The outside edge of my cavitation plates are still under water while on plane with level trim.

The cavitation plates are approximately 2.5-3'' above the bottom. They were about an inch and a half before they were raised. The boat also has about 24'' of set back on the transom.

My buddy who raised them for me owns a huge dealership of Wellcraft and Fountain boats. Both often come with Verados and he has told me that 80 percent of manufacturers of boat he's seen have the motors too low. He says they can still come up more without a problem.

Additionally, the Rev 4's I'm running have a ton of bite. I was hauling arse back home to avoid a thunderstorm (about 45 mph) and went across a sportfish's wake...all 5 ft. of it (without tabs because they were broken)and launched the hull but the motors still somehow never broke loose with the units buried and the hull aired.

I also was able to catch up to a 26 Island Runner on his way out (we were both running on the pins) and never broke loose at all even with getting a little air off a couple waves.

I still have not had ANY issues with blowing out and the REV 4's just keeping biting regardless.

I am running 250 Verados. I have not really had a ton of water rough enough to see how she handles but without tabs she will take a 2 ft. chop, chew it up, and spit it right back out. As time goes on here, it will gradually get rougher as winter comes so I will report to the ride. She is very dry. She will pound in the tiny bit of rougher water experience I've had but I didn't slow down...I feel she rides better going faster since she likes to ride on top.

The boat handles great. She loves to run. Making sharp turns on plane is never a problem. I do not have ADS (20K!). It's just one more thing to break. The motors were mounted 2 holes below the top hole from the factory, so we raised them two to the top hole. They are mounted all the way up.

If I had low water pressure to any of the cylinders, I would know by a loud and obnoxious beep complimetry of the Smartcraft system and the digital System View offered with the Verados. I get alarms even when I air out the pitot/trans for the system. I will check the water pressure next time, but if I was roasting the top cylinder, my computer would probably let me know. I will keep an eye on the water pressure next time. Thanks for bringing that up.

posted 09-06-2005 03:31 PM ET (US)            

It is not possible to raise them anymore so they are staying where they are.

posted 09-07-2005 08:24 AM ET (US)            

I switched from 17P Mirages to 17P Revolution 4s late last year and have used the Rev 4s the entire season this year. The ride of my 27 Whaler WD has improved significantly. I lost about 2 MPH of top speed as a result of the switch. Fuel economy is just ever so slightly less overall with the Rev 4s (they are actually better at the slow plane speed because they don't lose their grip) but the significant improvement in the ride makes it well worth it. The boat can be held on a slow speed plane with no difficulty now.

I think the problem with the Mirages is that they didn't have enough blade surface area to carry the load properly. They were fine on smooth water above 28 MPH but not so good when slower speeds are desirable, such as when traversing 2 to 3 footers.

I expect that the Conquest 305, being a heavy and wide boat would have the same problems with ride and cavitation in a rough sea state. I expect that it would certainly benefit from 4 blade propellers. Hopefully, Mercury will come out with a left hand version of the 15P Rev 4. I think a pair of 15P Rev 4s would probably be ideal for the 305 Conquest/Verado or Optimax combination.

posted 09-07-2005 12:56 PM ET (US)            

The quickest 320 by far though that another friend owns is rigged with Twin Yamaha 300 HPDI's which are lighter and more powerful, now that 320 really flys. It ran easily over 56mph with fuel and 4 people on board. Sounds fantastic too.

Verado's are great to use and are very quiet, good allrounders and super smooth but if you want to go quickly in a 320 the YAmie 300's are superb.

posted 09-07-2005 07:35 PM ET (US)            

Those motors have been blowing powerheads as long as they've been out along with some 250's.

Stay away from Yam 300's....run...far.

If you are an owner with a lucky set, all the better, enjoy your motors.

Sideshow,

With the weight and overall design of your boat, it is not a speed demon and as you said, you don't need it to be either. The 305 is a lot of boat.

When you get your motors raised, check your WOT RPM and your fuel burn. Your fuel burn will likely be better and RPM's will go up some at WOT. If you find you are breaking out and running over 6000 RPMs, you may want to try out a pair of 17p Rev 4's....they will certainly give you a ton of bite, may take your fuel efficiency down a tad, but you will have great control at the dock and good bite offshore. I think your situation may just be okay if you are running 15p Mirage 3 blades even with the motors being raised. I don't know when counter rotating 15 p 4 bladers will be available...but hopefully soon.

Check your stats now...if you are getting your good RPM's at WOT, that's great. If you are getting better fuel efficiency, all the better. Run her in some rough stuff and following seas and see if the motors blow out at all. If not, I don't see the need for 4 bladers or lowering the motors. I think 17P is a little big for a big boat like that to swing so check your stats and report back here if you can...

In my opinion, if you are not blowing out with 15p Mirages and you are getting better numbers across the board as far as fuel efficiency and RPM's at WOT...the 15p Mirages are probably as best as you can do...because 17p rev 4's, I think, will suck your fuel efficiency back down a little bit along with speed and RPMs. Check it out and let us know what you find...

I also would not worry about frying your cylinders furthest away from the water pump. The Verado has a low-water pickup.

posted 09-09-2005 08:35 PM ET (US)            

You make a good point. However, the YamaMerc and the Verado are two completely different motors. The Verado should spin at least 6000 in my opinion...this is a good indicator that the boat is not overpropped, the motors are not buried, and that the motors are under such a tough load to only be able to spin under 6000. The rev limiter on the Verado is set around the mid 6000's, I believe. So, let's say you can turn 6500 max...which not a lot of boats can unless they are underpropped or they have the perfect situation.

Even though your YamaMercs can turn in the middle of their range, the Verados turn in the 6000's at WOT...or they should at least. That is why I think the 15p Mirage is a good prop for a heavy boat that will turn the RPM's the Verados will run at. This proves they are not under too much stress to push the load.

However, if Sideshow starts having cavitation issues, I would recommend trying out a set of 17p Rev 4's and keep the motors right where they are. Chances are, he will lose some RPM (not drastic), but he will have plenty of bite for the height they are at. If he is not having cavitation issues, then why fix something that is not a problem? The 305 is undoubtedly heavier (I can only assume) than the 320...however, my 320 with the motors at the height they are at, have not much of a problem turning 6100ish RPMs at WOT. I'm interested to see how the Mirages will run with them jacked up...he may have to get some Rev 4 17p, but when he reports, we will see!

posted 09-20-2005 08:53 AM ET (US)            

Top Speed: Increased from 37knots to 42knots.

Maximum RPM: Increased to 6150rpm. Can't remember what is was before, think it was around 5600 - 5800rpm.

Holeshot improved noticably.

I still have the original 15inch Mirage props. Conditions today where quite good with only a small chop. Will see how the setup goes in offshore conditions on the weekend with the raised engines. Haven't done any fuel consumption comparisons yet however I would assume an improvement at cruising speeds.