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Water Ski Engine Size

Mr. Jones

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Looking at building a new 16' boat with either a 70HP Yamaha four stroke that I'll flash to an 80 or 85HP or a old Yamaha two stroke 90.

I like to water ski sometimes and would probably use this in the bay to ski ever now and again. The skiers would be 120-160lbs and are all pretty decent single skiers.

Opinions on whether this engine size is enough to ski for a few laps? Nothing serious.
 

boatpi

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Been down that road many many years ago as I started waterskiing at five. depends on how many people in the boat and of course the hull design I would be much more inclined to go with a 110.

A water skiing day started in a Long Beach channel with about a 1959 skipjack with about 100 hp Merc two stroke but then I was only about 75 pounds. My last long ski trip was to prove a point at 55 years old. The entire length of Lake Havasu went through a tall cold one in my board shorts during that little trip.
 

Mr. Jones

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Been down that road many many years ago as I started waterskiing at five. depends on how many people in the boat and of course the hull design I would be much more inclined to go with a 110.

A water skiing day started in a Long Beach channel with about a 1959 skipjack with about 100 hp Merc two stroke but then I was only about 75 pounds. My last long ski trip was to prove a point at 55 years old. The entire length of Lake Havasu went through a tall cold one in my board shorts during that little trip.
Thanks. This particular hull (Tuff) has some weight restrictions apparently. I think they like to keep the motors 275 lb or less. I've been debating whether or not adding 75lbs with a Yamaha 90SHO that's flashed to 120 horsepower would really make that much of a difference in balance.
 

DarkHorseRacing

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If you give the boat the opportunity to get some speed up the momentum can pop the skier up, but it can be a bit of a pull.

We used to ski behind a little ponga in Cabo, we would have the ski line out and then take off in an arc of the ski line and when we got about parallel to the skier turn and go straight.
 

77charger

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When I was a kid I could get up on 85hp 18ft 1960s style deal. And prob about 120 pounds lol.

So I’d go for the 90hp
 

Desert Whaler

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I have a Yamaha F70 on my 1988 Boston Whaler 15.
I've pulled up skiers on singles w/ no problem. Wakeboards even easier.
I run a Turbo FX4 13.25 x 16 4-blade that I had Augie at Cutting Edge true-up, balance, and put a little cup in for me.
I run a Bob's 5" Manual jackplate to offsett the added weight I have in the boat.
Very happy with this set up for my application & needs. Little motor has plenty of low-end grunt for it's size. (2.33:1 gear case)
Another very good prop for the F70 is the Powertech SCD4 (Semi-Cleaver Design) . . . I've never tried one, but have heard nothing but goods things about it.

I'm VERY happy with the F70 . . . . I had a Yamaha 70 -2-stroke on it before. And while I do miss the little mid range 'powerband curve' of the 2-stroke from time to time . . . it's way offset with all the nice features and modern upgrades of the F70. I'd be curious how the flash for the F70 works out if you decide to go that route.

Link to my prop . . .

 

Ultra...Good

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For me the difference always came down to the prop. Use the lowest pitch that will achieve a speed slightly more then you will use and life is good.

That and a non ventilated prop make it WAY easier to plane at lower speeds, low speed maneuvers also much easier.

Stainless is a must and more blades seemed to work better. Always looked at it like having wider tires on faster cars. More traction type thing.

My last rig was a 17' open bow checkmate with v4-140 evinrude 2smoke. Ran a 24" raker to near 70 at best and could have pulled a skier. When I was pulling skiers I would switch to a 17" that would pull yore arms out of yore shoulders.

Would also plane out at a real low speed with the 17, non vented, and maneuver real well when retrieving or docking.
 

HST4ME

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2 stroke 90 yams are very good runners, few bits from hydrotec makes them better
 

brgrcru

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All I know is we had a 140hp I/o
On a 16’ boat growing up . With any one over 160 lbs. and 6 people onboard
Everyone on the boat had to crowd the driver . When we were skiing until skier was up and then ,It was a race to any seat in the boat . Like musical chairs .
 
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