Outboard repower options

[mariner125]

Hello,

I am thinking of repowering my ski boat. Currently I have a 125hp Mercury 2-stroke on the back of a Stejcraft Silhouette (17ft social ski boat). I was looking at the 135hp Mercury Verado supercharged 4-stroke or the Honda 135hp 4-stroke. The boat's primary use is waterskiing, getting some big blokes (95+kgs) out of the water.

I was wondering if any one has experience with these motors for their suitability and hole-shot/torque for waterskiing.

The other option is sticking to 2-stroke with a direct injection motor, ie-optimax etc.

Is the economy (when skiing) of an DI 2-stroke comparable to 4-stroke?
Is the pulling power/holeshot similar between 2 and 4-strokes?
Is ongoing servicing costs the major concern between the two?

Any thoughts/experiences would be appreciated.

[bep078]

When comparing a 135 Hp verado to a 135 hp optimax, there is a huge difference. First off, the opti is a 2.5L V6 engine, While the verado is a s cylinder 1.7L Therefore the opti would have more grunt than the verado. The verado is also about 30-40 kg heavier than the opti. The MSRP of the Verado is $12,300. While the opti's is $11,600. i'd personally go for the opti. The reason being that for a cheaper price, the opti has 2 more cylinders and cubic capacity, hence more torque, and to ski people, you do need some grunt. Dont get me wrong, the verado will do fine, but once you start revving that 4 stroke, it will consume more fuel than the opti which would be producing the same amount of power, but at greater ease.

[David]

135 Verado = 510 lb, same as 150 and 175 "dry", ie add oil to that
135 Optimax = 431 lb, same as 150 and 175
135 Honda = 478 lb "dry", ie add oil to that
150 HO Rude = 419 lb
115 Rude = 369 lb
your old 125 probably weighs 348 lb
150 Yammy 2 stroke = 468 lb

In general:

1. extra weight on the transom will not help you pull a skiier
2. 4 stroke outboards have less low rpm torque than two strokes
(See 2007 Rude brochure, it shows HP and torque curves for their 150 and a 150 Yamaha)
3. You can make up for the lack of torque on a 4 stroke with a supercharger, at the expense of fuel economy, weight, and emissions - that ought to start something:)
4. The DI 2 strokes are reputed to have better low end torque than the old carb or EFI motors

If it were my money, I'd go for the 150 HO, but an Optmax or a Yammy HPDI would be good choices too.

Of your 4 stroke options, Verado vs Honda, for skiing, I'd take the Verado

500+ lb is a lot for a 17' boat (5.2 m?)

[150aintenuff]

PERSONALLY i would find a 1999-2000 2.5L EFI 200.. 404lbs.. and overkill in the Hp department for pullin yer skiiers if a 125 does it fine now.. and its lighter than all the newones listed and cheeper to boot... the money saved can get ya an SVS a PCM and a few other hop up parts and a full 225-250 HP could be realized and save fuel over ANY verado and honda every day of the week... the 150 Verado burns 20 GPH approx.. where as the 200 Efi conventional 2 stroke burns 19 and the opti burns like 14-15.... a 135 opti is a DOG of a motor... go 150-175 the 135 is way to lean and looses torque because of it.. the 150 and 175 are 100% better in torque and HP than the 135 is....

[The Big Al]

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[150aintenuff]

also look at the 140 and 150/175 suzuki... light and fast for 4 strokes..

[bep078]

I'd go for the 135 or 150 opti, mainly for the grunt.

[captcarb]

I have an 18 ft skiboat with a 1995 Johnson carbureted 150 which weighs 370. This is one of the lightest V-6's and is the reason I bought it.

If I were going with a new motor it would be the 150 Evinrude e-tec or the 150 Optimax in that order because of the complex nature of the Mercury. I do not believe you will be happy with any 4 stroke outboard on that boat.

I would not buy one of the new motors though. I weighed some Mercury parts the other day and calculated that by using the lightest midsection, the lightest block etc that I could build up a 200 carb or laser injected merc that would weigh about 360. It would be noisier than the Johnson that I have now I think.

[ghind]

I happened to go for a ride in a Stejcraft Silhouette last weekend. They are a small boat. Don't put a heavy motor on the back, you will regret it.

Get a hold of the Evinrude brochure, it is interesting reading.

The other thing to be aware of is your boat is only rated to 140hp. That is the MAX for that boat and they were designed for a light weight carby motor. DFI's are generally heavier and this should be your first consideration. Four strokes are much heavier again.

4 strokes are more expensive to service, have less low down power and are heavier. They are not really a ski motor, although there are exeptions. For example, the sea world guys are very happy with their honda 225's on their haines boats but they can probably float a bigger motor than most ski boats. I more consider the sea world boats as bay boats than true ski boats anyway.

Optis are reported to have as good or better fuel figures than 4 strokes.

How many skiers are you looking to pull? Doing what? Slalom, two feet in? It would be a lot cheaper to learn to start dragging a leg (let me know if you need to know how).

E-TEC isn't an option, they don't have anything around the 140 max mark, the sizes are 115 and 150hp.

Yamaha HPDI starts at 150hp so that is out too.

And if you were spending $15-20K on a motor, I would suggest selling your whole boat and buying a new one. Your current boat and motor will be worth more as a package than you will get for your old motor seperately. Then you have a 20k motor on a boat that really won't ever be worth more than $30k, probably less. Your boat is probably worth $20k+ now and might be worth $27k in two years time with an 07 135 Opti.

Actually scratch all that. I've just looked at the Merc site, the 135 opti weighs 195kg. That is way too much for your boat. You could ask the Stejcraft factory, but I just wouldn't do it.

If you are after pulling power, have you tried a high five prop?

A guy up the road from me just sold a Stejcraft Silhouette with a 115 Opti. A great boat, but an expensive motor for what is an entry level boat. For that money, you have a lot of choice in second hand boats. It took more than 6 months to sell and probably sold at a discount to initial asking price. As I said, a great boat, but people will only pay so much for a smaller entry level boat no matter how good the motor is.

What is wrong with your current motor?

I've just bought a new Stejcraft Pro Skier outboard and have fitted a 225 Yamaha Vmax on it. I've always liked the Stejcrafts. My last one of these pulled 4 men on slalom with a 150 yamaha and I will set this one up to do the same or maybe 5.

EDITED: The boat up the road is was a 16ft Stejcraft Silhouette with 115 opti not a 18ft Skier.

[ghind]

One more thing, the Stejcraft Silhouette is a 16ft boat including integral boarding platform which, from memory, isn't a normal part of the running surfaces so it is really more like a 15ft boat.

[mariner125]

Thanks ghind,

I really just want more oomph down low and economy from the motor that DFIs can give. Currently the 125hp motor on it weighs 158kgs, in your opinion would the extra 37kgs make that much difference? I really love everything about the boat and am not looking to change it. The looks, handling and size suit my use just fine.

Also, can you tell me how you drag a leg.

Thanks for your input

[ghind]

Thanks ghind,

I really just want more oomph down low and economy from the motor that DFIs can give. Currently the 125hp motor on it weighs 158kgs, in your opinion would the extra 37kgs make that much difference? I really love everything about the boat and am not looking to change it. The looks, handling and size suit my use just fine.

Also, can you tell me how you drag a leg.

Thanks for your input

How many skiers can you pull now and what prop do you run? What RPM do you achieve when you wind it right out?

37kg is a huge increase. Also what steering do you run? This weight will be in the worst possible place in the boat, high up on the very back.

What economy do you get at the moment?

I'm low on time at the moment, will explain how to drag a leg tonight.

[mariner125]

I am running a stainless three blade prop by Michigan Wheel, it is a rapture 21" at WOT the boat will do 52mph @ ~5700rpm. I can get two skiers out (feet in) with a bit of effort.

Current steering is rotary push/pull. I am burning around 18lph at a rough guess. The majority of running is slalom, kneeboards and kids on tubes.

[ghind]

That is a a good speed for that boat. Is it off GPS or speedo?

If you are looking for more pulling power, you could try a 19" high five with medium vent plugs in it. You will have to be careful not to over rev the motor at top speed, but how often do you need to go that fast? Should still be good for about 47+ mph (on the same scale as your 52mph) though.

If you go with a bigger motor, you should install hydraulic steering.

Where are you, in Victoria??

18lph isn't terrible, it is probably the tubes that are the worst.

Given you can pull 2 skiers two feet in, you should probably be able to pull 3 good leg draggers.

To start dragging a leg (for right foor forward):

* Keep your right knee bent and up against your right shoulder
* You want to stay over your ski as you come up. i.e. right knee directly above right ankle
* let your left leg drag out at full length behind you. Don't bend the knee, keep that leg straight. It helps to push on it, but push on that whole leg against the water as if it was another ski.
* The idea is to easily allow the ski to slide up on top of the water, parallel with it and for you to make as little resistance as possible.
* Obviously the ski starts verticle and rolls out flat above the water as you take off

Get the driver to take it very, very easy. It is a lot easier to learn slower and also, you want to learn how to do it slowly for multiple starts.

This start method is a lot easier on your body and is a lot easier in general once you can do it. I always start this way. You just don't drag.

You know you are good at it when you can get up on a trick ski or a 5-6 ft fence paling this way.

The summary. Right shoulder over right knee directly above right ankle. Driver be gentle.

I can try and get some photos if you PM me your email address.

I think you pretty much have the right motor for your hull. You could chase better economy by installing a 115 opti.

If you want a bigger outboard, sell your current boat and get a nice late 1990's Stejcraft Pro Skier outboard, maybe sell the motor off that and put a 2 stroke DFI on it.

Greg

[mariner125]

Greg,

Thanks. The speed is tested with GPS. I am in Adelaide. I have had a look and cannot see a 19" high Five for my model. They do have a 20" though.(http://www.propline.com/Select-Boat-Props-By-Brand/Mercury-Propeller-Company/High-Five-Stainless-Steel-Propellers/50_HP_4_Stroke_60_Bigfoot_75_125_HP.htm) Do you suggest getting props from the US or are there cheap places in Australia.

I will PM for those pics if possible.

[David]

I have pulled out on one ski behind a 115 Johnson effortlessly, as has my 90 Kg brother.

A 115 ETech would have even better pulling power than the carb'd Johnson, and its a light motor as DI and 4 strokes go.

[ghind]

I'm not sure about the 20" high five. They are a smaller diameter and I don't think they will have the traction to pull 3 on slalom. I could be wrong.

Ring up precision props in melbourne. They can repitch your current prop or put you on to others. They are really, really good.

If you can pull two with two feet in now, you might be able to pull three dragging a leg as it stands.

[150aintenuff]

the hi 5 will jerk your arms off... go pitch for pitch the 20 is FINE for your aplication.. will rais your RPM 200-300 on top at same speed... BUT you may have to raise the motor up a bit to fully utilize its ailities over the rapture... dont get me wrong the rapture is a good prop... jst not in the hole shot department... they are a cruiser prop for those of us that like to stay in the mid to upper RPM range and dont really care about ultimate in hole shot.... the high 5 is ALL hole shot and mid range... you will LOVE it for skiing... on my fissin boat a 19 high 5 will LAUNCH the boat and flawlessly pull up tandem slalom skiiers weighing over 250lbs( about 125 KG) each.. the 21 rapture struggles to pull 1 up on slalom.... the high 5 lies a bit more engine hight on the top end than the rapture but likes to be a touch lower at hole shot.. so a short setback hydraulic jack may be in order say bobs 3" plate.. but no more if ballence is the way you like it already.. keep the 125 or find an older lighter 2.0L 150 V6 and rebuild it.... 370 lbs is easilly obtained with a bit of parts lightening and a few part eliminations along the way..

[mariner125]

As a general rule, going to a lower pitch number with the same amount of blades will increase rpms and lower top end speed. Is the same true for when moving from a three to four blade prop. When I get the boat on the water again, I will ensure that I have the right top end speed and rpm readings to make sure I select the correct prop.

[ghind]

The high five is a direct replacement pitch for pitch with a 3 blader. They are made to take the rpm changes into account.

I absolutely agree that the high five is the best prop for multiple skiing and barefooting. They are a bit weak in reverse, no big deal but that is their main weekness plus you lose a little top end. Who cares when you already have the speed you do.

The 20" is a smaller diameter and it will make your boat get up very quickly. What I am not so sure about is how well it will pull multiple skiers. You need traction to pull out three on slalom. It will probably do it, but I would want to try one first.

The 19" will certainly do it as it has a bigger diameter. But it may not fit your motor.

I know the even numbers are designed for the small motors and the odd numbers for the v6's but I believe they both will fit the same shaft. Ring precision props. They may also put you onto a good second hand one.

[captcarb]

If you want to pull harder, just put a 17 pitch on it and watch the rpm's on the top end. It will pull MUCH harder. When you want to run flat out, just change props. That is what I do.

jim