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tntut1
07-30-2010, 12:14 PM
Greetings to all you fellow boaters from a new member and prospective Donzi owner. I'm hoping to obtain feedback/advice on two issues. First, I'd like to acquire a 90's area Classic 16 or 18, but am unsure which craft is best. What do you guys think?

Second, I float at higher altitude (5000ft) and am concerned about what steps will be necessary to allow a 16 or 18 to run well. The ones I've found for sale are all in low altitude areas, so I guess an outdrive rebuild, and perhaps staying away from the OMC products since parts could be an issue. What do you guys think? Go Mercruiser? Would a re-prop to a low pitch be enough on one of these small hulls?

Thanks guys.

Marlin275
07-30-2010, 12:25 PM
Go with the 18
more room
better ride
best handling boat in the world for her size
more room to work on the engine

Donzi first made the 16
then they made it better -
the 18 - 2 + 3

The Donzi 18 is one of the longest production run
boats in the world.

GBond
07-30-2010, 02:01 PM
What Marlin said

gcarter
07-30-2010, 02:11 PM
Donziweasel, who I think lives in Jackson Hole, boats at about 6K+ '.
He had some iissues, but eventually got to where he wanted to be.

For just two feet, the 18 is in a different solar system from the 16.
Unless you boat on a very small lake, the 18 is a much more satisfying boat.

tntut1
07-30-2010, 03:10 PM
Thanks for the feedback guys, I'll have to look up the Donziweasel. The 18 does appear to have a better hull design correcting the 16 porposing issue, but will trim tabs also do that? The market has more 16 for sale and the price difference is notable. The 18 in some cases are twice the price. Is the 18 really that much better?

glenncal1
07-30-2010, 04:00 PM
If you are looking at later model boats (16 or 18) grab one with EFI for the altitude. My big boat Searay 265 has two 6 cylinder mercs that are the MPI model. They ran good at sea level in florida where I bought the boat, they run good here in the mile high city. You will loose about 15% of your power at 5000' compared to sea level so you may need to drop some pitch in the prop.

gcarter
07-30-2010, 04:45 PM
Is the 18 really that much better?

Yes!
Be patient.
And don't just shop price.

mattyboy
07-30-2010, 04:48 PM
The one big advantage of the 18 is the comfort of the passenger that the front buckets give. the 16 is better at water sports and lounging around the lounge seating in the 16 gives more room to move about the cockpit but the 18 gives more room in the bilge with a V8.

the ride difference in the 2 is not that different the seating in the 18 gives a more in the boat not on the boat feel than the lounge seating of the 16. when it's rough in a 16 it is rough in an 18. When I came back from rough rides at the events the 18 owners came back beat up too come to think of it the owners of bigger boats came back beat up too well maybe not beat up but they were wet so it was rough ;). If my 16 had the newer 2 +2 seating I would still have it.

don't under estimate the 16 it is a very capable boat that once you get use to can be very agile and fun to drive.

you boating needs/style/area would really dictate what you need.



BTW they all porpoise 16 18 22 that is usually cured by the right prop if not cured at least controlled/ limited by the right prop.
tabs help when its rough or when the side to side balance is off. once you're used to the ride and setup right you'll use the tabs less and less

DonziJon
07-30-2010, 05:41 PM
My 20' Minx...does NOT porpoise at any speed up to max speed of just over 60. I am using the Antique Merc 21" Cleaver that came with the boat in 1986. Just sayin. :)

Sweet Cheekz
07-30-2010, 07:36 PM
I had a chance to run Mike O's great 18 at LG and it was a riot Does feel a bit bigger than the 16 but both boats ride great Like Matty said the 18 is not going to calm a real rough day over a 16 Both a very fun
Parnell

gcarter
07-30-2010, 08:57 PM
Maybe I should have been more specific. It's so easy to generalize impressions.
I think the main difference is the 18 responds more positively to engine inhancements, w/less hull modifications than a 16.
After all, the fastest classic in history was a 1000 HP (OK, 940 HP) 18 w/an Arnesson. It did 120+ MPH so effortlessly. To the best of my knowledge, it had a stock bottom. It was probably strengthened, but the bottom shape was unchanged.
An 18 has the room to have the more ambitious engines. There have been factory BBC's w/a TRS drive.....
I think an 18 handles an 18" chop better than any other Classic hull.
It has almost the same interior room of a 22 w/a 4' shorter hull.

But, if you like skiing, tubing, etc., you probably can't beat a 16.

Cuda
07-30-2010, 09:55 PM
My 20' Minx...does NOT porpoise at any speed up to max speed of just over 60. I am using the Antique Merc 21" Cleaver that came with the boat in 1986. Just sayin. :)
My Minx never porpoised either. My 22 did before I got the right prop on it. The Minx had tabs that I never used, the 22 didn't have tabs, but I could see inside the hull that it was made either for tabs or had tabs at some point.

Cuda
07-30-2010, 09:57 PM
Is the 18 really that much better?
It depends on where you boat.

RickSE
07-31-2010, 12:17 AM
Most of the altitude folks run a higher gear ratio in the outdrive, 1.68-1.83. All the boats that my dad sold in New Mexico came from Donzi with the higher gear drives.

tntut1
07-31-2010, 12:07 PM
Thanks for all your advice guys, and I can certainly see where patience and research are necessary. The closest 16 or 18 classics are about 1000 miles away. It also seems that most are in sea level regions, so an out drive rebuild may be necessary. In that scenario I worry about the gears being available for the OMC boats and may stick to a Mercruiser. I do have two younger kids (8,13) who enjoy wake boarding, tubing, etc...and the sweet 16 lounge would be an advantage. Do any of the Sweet 16 4.3 Mercruisers come EFI? Is that a throttle body EFI rather than multi port?:confused:

Marlin275
07-31-2010, 12:17 PM
I do have two younger kids (8,13) who enjoy wake boarding, tubing, etc...and the sweet 16 lounge would be an advantage.

18 s are great at ALL water sports
the wake alone is a blast!



http://www.donzi.net/forums/attachment.php?attachmentid=6480&d=1096126459

mattyboy
07-31-2010, 12:33 PM
Maybe I should have been more specific. It's so easy to generalize impressions.
I think the main difference is the 18 responds more positively to engine inhancements, w/less hull modifications than a 16.
After all, the fastest classic in history was a 1000 HP (OK, 940 HP) 18 w/an Arnesson. It did 120+ MPH so effortlessly. To the best of my knowledge, it had a stock bottom. It was probably strengthened, but the bottom shape was unchanged.


George, unchanged???? hook or rocker can be added at the driver's whim??? sorry not buying it ;)

tntut1
08-03-2010, 10:31 AM
Yeah you guys are on the money regarding these great little hulls. What about the U-17/19 series? I realize they represent an imitation, but have also heard they are very capable. The only Classic in my area is a poor choice due to its age and condition. There is a nice clean U-19 for sale locally that's already had the outdrive gears changed for high altitude. Would any of you be happy with a U series? I've read conflicting opinions on several sites.

HOWARD O
08-03-2010, 05:08 PM
I would PM Donziweasel, he's pretty familiar with altitude and a 16' and may be able to offer some good advice for you.

tntut1
08-06-2010, 02:09 PM
Thanks Howard O, your the second person to refer me to the donziweasel. I'll give him a try!

Okie2
08-06-2010, 03:05 PM
I have Donziweasal's old 16...he had it in Wy above 5000 feet...I have it in Ok around 1500 feet....I got maybe a mile or two more by coming down from the clouds. Couldn't tell you about the carbs...he changed them for me when I picked it up. Changed the jets? Scott

ps 16 or 18 are a handful...I don't let people drive my boat...it's a touchy S.O.B.!

Just Say N20
08-06-2010, 05:10 PM
Yeah you guys are on the money regarding these great little hulls. What about the U-17/19 series? I realize they represent an imitation, but have also heard they are very capable. The only Classic in my area is a poor choice due to its age and condition. There is a nice clean U-19 for sale locally that's already had the outdrive gears changed for high altitude. Would any of you be happy with a U series? I've read conflicting opinions on several sites.

The U-17/19 are decent boats, and I would not be concerned about owning one (if it had a Volvo outdrive, I don't know if they made any with OMC).

There are some subtle bottom differences between the Donzi and the Four Winns. I believe that the U-17/19 are slightly faster than the 16/18 Donzi with comparable power.

But, its not a DONZI. Some people are totally satisfied with a Yamaha that "looks and sounds" almost like a Harley, and other people would only own the Harley.

tntut1
08-06-2010, 06:26 PM
Quite right N20, there is no true substitute for an original. I'm asking about the U series becuase there are several for sale near Utah, but I can't locate a Donzi Sweet 16 or Classic 16 within 600 miles. Maybe something will turn up in the next month or two. Those little Donzi's have some serious style.

gcarter
08-06-2010, 08:41 PM
But, its not a DONZI. Some people are totally satisfied with a Yamaha that "looks and sounds" almost like a Harley, and other people would only own the Harley.

I'd rather have a Vincent.......

Just sayin'

Donziweasel
08-07-2010, 08:57 AM
Welcome. Altitude is a not a set of numbers. Each boat and engine react different to changes in altitude. NA motors fall off more than forced induction. A general rule is 3-4% loss of HP per 1000 ft over sea level. That nice 300 hp Merc 350 at sea level may have as little as 230 hp up here. My lowest lake I boat on is at 5800.

16 are a hoot to drive, but you can get beat up in them in anything over a mild chop. I would go 18.

If it is a carb boat, drop 2 jet sizes in the primaries and secondaries. Drop 2 pitches on the prop. If the boat struggles to get on plane or you can't get the RPM's in the 4800-5200 range, drop a gear in the drive. Once agian, each boat needs to be tuned individually. I have had 15 boats out here and 3/4 of them needed to drop a gear in the drive, including my 16. My 16 was a 56 mph boat where it came from at sea level. It ran 47 up here. I quickly changed that. Let me know if I can help.

Okie, I was running 60 with my 16. Though you said you were around 66-67. Pick up of 6-7 mph dropping 5000 ft. :)

tntut1
08-07-2010, 12:31 PM
Thanks for jumping in DW. Your considered the altitude dude on this site. Where do you float, Jackson lake, Jenny Lake, or up on big old Yellowstone? Your a lucky guy living in such a great location. I'm four hours south in North Ogden, Utah. I typically float on at 5000 ft and have had to work quite a bit with the local prop doctor while dialing in the right pitch and cup for my Chris Craft and Regal. I'm just hoping to avoid gear ratio switch in the drive. Especially since many of the Sweets have an OMC Cobra product. I have a King Cobra on my Chris Craft and really feel that its one of the best drives I've ever owned (on my 7th boat now). But my repair buddy hates OMC part availability and often encourages me to sell. There's a 1990 sweet 16 for sale in Oaklahoma (Tulsa Craigslist) right now, is that your old ride?:cool!:

Donziweasel
08-08-2010, 04:31 PM
I mainly boat on Palisades, but occasionally hit Jackson Lake during the week when the Park Service is not out. My Criterion has a 540 and is on the cusp of being to loud for Jackson.

King Cobra is a great drive. I can see why you wouldn't want to drop a gear. Hard to find and probably expensive. All my experience has been with Alpha's and Bravos. When I finished with my 16, it had 377 dynoed hp at sea level. Up here, with a 1.65 it ran 60-61. I dropped the gear when it only had around 340 hp. Probably would have been alright with the 377 hp.

Like I said, not an exact science. Best thing to do, pick your Donzi and give me a base set of numbers (what prop, rpm's at WOT, GPS speed, how does it plane) and we can go from there. We will get her dialed in for you.

My 16 originally came with a 350 2 barrel. First, I got a set of Edelbrock heads, intake and a comp cam. Put a 600 cfm 4 barrel on it. Really woke it up.

The one for sale in Oklahoma can't be mine, mine was a 1997. Mine originally came from Iowa.

Good luck!! :)

DonziJon
08-08-2010, 07:26 PM
Just a suggestion: I won't get into how I know this except that I know something about Aviation.

When an NA aircraft is climbing to altitude..at about 4000 feet above sea level, the pilot starts to "Lean" the mixture. The higher you climb..the more you lean the mixture. Pilots have this capability at their fingertips on the panel (dashboard)..a "mixture adjustment" on the fly.

Boats don't have that option because that requirement is not usually required.

Boats DO have an option...supercharging. ALL your Altitude problems GO AWAY. NA Military Aircraft (old) use this feature above 18,000 feet...to get them up to 32,000 + feet. :yes:

Note: NA= Naturally Asperated....more specifiaclly..Carburated.

GBond
08-08-2010, 09:16 PM
Very good point Jon!

Donziweasel
08-09-2010, 07:46 AM
A normally aspirated engine is either fuel injection or carbureted. It simply means lack of forced inductions, ie. a supercharger or turbo. A supercharged engine if carbureted will still have to be re-jetted for altitude. There is simply less O2 in the air up here. Regardless of NA or blown, the mixture of fuel to air will still need to be adjusted due to less O2.

The Hedgehog
08-09-2010, 01:31 PM
Just a suggestion: I won't get into how I know this except that I know something about Aviation.
When an NA aircraft is climbing to altitude..at about 4000 feet above sea level, the pilot starts to "Lean" the mixture. The higher you climb..the more you lean the mixture. Pilots have this capability at their fingertips on the panel (dashboard)..a "mixture adjustment" on the fly.
Boats don't have that option because that requirement is not usually required.
Boats DO have an option...supercharging. ALL your Altitude problems GO AWAY. NA Military Aircraft (old) use this feature above 18,000 feet...to get them up to 32,000 + feet. :yes:
Note: NA= Naturally Asperated....more specifiaclly..Carburated.

Actually civilian airplanes are often turbocharged these days. It is nice to get you over the weather.

Being able to lean the mixture on the fly is cool. Makes it easy to clean the plugs. You got to watch the EGT's though. I could see some scary things happening with a variable mixture control on a boat!

DonziJon
08-09-2010, 07:37 PM
When you climb above 4000 feet above sea level in a piston powered (Non Turbo Charged) aircraft, as you continue to climb, the engine seems to lose power..become sluggish...your altitude gain ..feet per minute.. decreases. Not good.

There is a mixture control knob on the panel that is a "plunger"...push-pull thingy. You can push it in to Full Rich..(used for takeoff) or pull it out to full lean. (Engine stops) Push-Pull is the course mixture adjustment. In addition, you can "Screw" adjust the knob for Fine adjustment of the mixture.

Here's how it works. As you climb, ...the engine will lose power, so you "Pull" the mixture knob out a little more (toward lean) and the engine will respond by increasing in RPM. Keep pulling the knob... and the engine will eventually "faulter". When it does...Push (or screw) the knob back in just a little until the engine regains its Max "Vigor". You repeat this procedure as long as you continue to climb.

A small general aviation aircraft (no turbo) maybe can get up to 15,000 feet. Add a turbo...and ....it's a whole new ballgame. :yes:

In a BOAT at high altitude, your lake is at a Constant Altitude, so adjustable mixture is not necessary.....as DW said, re-jetting takes care of this. BUT supercharging makes up for the lack of oxygen in the air and you keep your power. :nilly:

As Hedge said, EGTs (Exhaust Gas Temperature Sensor) is nice to have but you can do it without by "Feel".

The Hedgehog
08-09-2010, 08:03 PM
When you climb above 4000 feet above sea level in a piston powered (Non Turbo Charged) aircraft, as you continue to climb, the engine seems to lose power..become sluggish...your altitude gain ..feet per minute.. decreases. Not good.
There is a mixture control knob on the panel that is a "plunger"...push-pull thingy. You can push it in to Full Rich..(used for takeoff) or pull it out to full lean. (Engine stops) Push-Pull is the course mixture adjustment. In addition, you can "Screw" adjust the knob for Fine adjustment of the mixture.
Here's how it works. As you climb, ...the engine will lose power, so you "Pull" the mixture knob out a little more (toward lean) and the engine will respond by increasing in RPM. Keep pulling the knob... and the engine will eventually "faulter". When it does...Push (or screw) the knob back in just a little until the engine regains its Max "Vigor". You repeat this procedure as long as you continue to climb.
A small general aviation aircraft (no turbo) maybe can get up to 15,000 feet. Add a turbo...and ....it's a whole new ballgame. :yes:
In a BOAT at high altitude, your lake is at a Constant Altitude, so adjustable mixture is not necessary.....as DW said, re-jetting takes care of this. BUT supercharging makes up for the lack of oxygen in the air and you keep your power. :nilly:
As Hedge said, EGTs (Exhaust Gas Temperature Sensor) is nice to have but you can do it without by "Feel".

Yep, we lean planes without EGT's by pulling the mixture to the lean side of peak and then adding some juice back. You will feel and hear it. That would be kind of hard on the engine of a loaded boat.

tntut1
08-10-2010, 07:38 PM
All solid approaches for making motors run faster! Now I need to find a good Sweet 16 or Classic 18 someplace near Utah. Shipping costs are far too high to make an east coast boat a real option. I'll get back with DW once a boat is ready to be tweaked!

There's an older Hornet in Wyoming right now, but it really looks like a total restoration is in order, and I want to find something that can float right away. A friend of mine may sell his Minx III in Colorado, but he's not sure he's willing to part with her. Oh well.

DonziJon
08-10-2010, 07:49 PM
All solid approaches for making motors run faster! Now I need to find a good Sweet 16 or Classic 18 someplace near Utah. Shipping costs are far too high to make an east coast boat a real option. I'll get back with DW once a boat is ready to be tweaked!

There's an older Hornet in Wyoming right now, but it really looks like a total restoration is in order, and I want to find something that can float right away. A friend of mine may sell his Minx III in Colorado, but he's not sure he's willing to part with her. Oh well.

What is a MINX III..?

gcarter
08-10-2010, 08:19 PM
There's a ton of boats in the Mid-west.
Many sellers would be willing to meet you part way.

tntut1
08-12-2010, 01:18 PM
Your dead on regarding midwest boats, but I'm trying to find one that's at decent elevation and avoid having to swap out the drive gears. There's a nice Sweet 16 in Oaklahoma, but at 65 feet elevation and I'm at 5000 feet. I'll keep trying the New Mexico/Denver/Boise/Reno/Las Vegas/etc locations for a nice 16 or 18 with at least a mid level gear set. This will be a third boat for me to just have fun cruising and pulling water toys.

My buddy identified his Minx as a III, and said that's how it was identified by the previous owner. The previous owner told him that the Minx was built for three years and this one was procduced during the final year, hence the III designation. Not sure how acurate that is, but I've driven his Minx and its very nice. He remains undecided and I suspect will keep the Minx for a while longer. There are two nice Minx for sale in Seattle, but once again I'll have to redo the drives on either one. Oh well! Will be taking me Regal out this weekend for a good float! Hope you guys get to float your Donzis as well!