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  Repower with Twins: 18-Outrage (1983)

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Author Topic:   Repower with Twins: 18-Outrage (1983)
gvisko posted 10-26-2002 12:05 PM ET (US)   Profile for gvisko   Send Email to gvisko  
I want to repower my 18-Outrage with twins
Which is the best route to take?
Do I need to replace steering?

thanks gvisko

Bigshot posted 10-28-2002 10:34 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
No need to replace steering. you just run a tie bar from engine one to engine 2. Obviously everything else will need to be changed and depending you may need to run another full line from the tank.
gvisko posted 10-28-2002 07:20 PM ET (US)     Profile for gvisko  Send Email to gvisko     
Thanks nick that helps me alot. What motors
should I be looking at ? evinrude makes
75hp with ficht only whould like to get two
with carbs. IT would be a little cheeper
Iam open to advice.

Thanks gvisko

lhg posted 10-28-2002 08:00 PM ET (US)     Profile for lhg    
As one of the few participants here with a twin engined 18 Outrage, I can say that you MUST have Teleflex SIDE mount cylinder hydraulic steering for the boat, to deal with twin engine prop torque. See Reference section for information and photos of my Whaler. Although a front mount hydraulic cylinder will work, the side mount, installed between the engines, is by far the cleanest installation, and least expensive. The cylinder should go into the tilt tube of the starboard engine.

There is much prior discussion to be searched out on this subject.

Regarding engine choices, keeping total weight of engines in mind, I think you have six choices realistically, beginning at the lowest HP:

1. Merc/Yamaha 4 stroke 60's, or Merc 2 stroke 60's. Speed and power will be limited to about 40mph

2. Yamaha 2 stroke 70's. Speed not much better than above. One fellow here had such a setup, and said he would like more power.

3. Mercury 75's. Probably the most powerful alternative within the boat's HP rating, if that is an issue for you.

4. Yamaha 90's. Very popular light weight 90's. I would definitely prefer these over the same size 70's. Bigger block and more alternator output.

4. Johnson 2 stroke 90's. Good strong engines, and I would not worry about the excess HP. This combination is probably no faster than the rated 150HP single. The REAL downside here is NO integral oil injection tanks on the engines, a space and rigging problem. This alone would prevent me from using them.

5. Mercury 2 stroke 90's. Same comment with respect to HP, but a little bit lighter at 303 lb each, and possibly faster than the Johnsons. High alternator output for todays electronics. When and if I had to repower, this is what I would get for my own boat.

As mentioned, a HUGE plus for Mercury and Yamaha in these hp ranges is the oil tanks installed under the engine hoods. The 18 with twins has no real place for them, considering there are already twin batteries in the spashwell, and the console is needed for scarce dry storage.

Twin 4-stroke engines for this Whaler above 60HP, are still a problem waiting to be solved by lighter weight engines in the 70-90 HP range. I think the current offerings of all manufacturers are too heavy for the boat. I don't know what Ficht 90's weigh, but they could be one possibility for clean technology above 60 HP.

Don't ask me why, but you will find the boat rides smoother and handles better with twins.

gvisko posted 10-28-2002 08:45 PM ET (US)     Profile for gvisko  Send Email to gvisko     
Thanks, Larry. This is a big help . I like the Mercury 90-HP engines. I will keep you posted. Iam going back to research the steering.

george visko

jimh posted 10-28-2002 09:01 PM ET (US)     Profile for jimh  Send Email to jimh     
I just converted the steering on my twin engine installation from a (older) center actuator cylinder to a new HC5370 side mounted cylinder. The conversion cost about $300, but it was worth it just for the reduction in clutter and cables.

The side mounted cylinder steering allows the hydraulic lines to the actuator to be fixed, since the actuator does not move back and forth (as it does with a center mounted unit). This means you can dress the lines and secure them in place.

I have an article coming on this conversion but I need to get the pictures take for it. Some day soon, I hope.

JohnAz posted 10-29-2002 06:51 AM ET (US)     Profile for JohnAz  Send Email to JohnAz     
I run 2 40hp Evinrude's on a 20ft Center Copnsole boat, 2,000 lbs dry weight,,It runs 35mph [gps], and with a lower pitch prop gets 22mph on one engine,,I realy like the feel of 2 engines and sound,,
bsmotril posted 10-29-2002 10:44 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Don't forget the Suzuki 70HP Four strokes at 335lbs.
BillS
Bigshot posted 10-29-2002 11:48 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Larry is on the money. I do not know about doing twin 70 ms's at 335lbs. I think I would opt for the 60 Mercs. I would also look into Tohatsu. You can get their 70's for $4775. The 90's are the same weight I think.
tully_mars posted 10-29-2002 12:02 PM ET (US)     Profile for tully_mars  Send Email to tully_mars     
I just wanted to 2nd the opinion on Hydraulic steering, it is a must. I friend of mine has an 86' Outrage 18 with twin 70hp Johnsons and he said the torque was so bad he had to put all his weight and two hands to turn it. He has since installed hydraulic steering (Sea Star) and it is much better.

Tully Mars

chiefmike58 posted 10-29-2002 04:52 PM ET (US)     Profile for chiefmike58  Send Email to chiefmike58     
GVisko, how much fuel capacity do you have? I would imagine twin anything will eat up fuel pretty quick compared to one large single.
george nagy posted 10-29-2002 05:23 PM ET (US)     Profile for george nagy  Send Email to george nagy     
that would be a 63 gallon tank for the outrage 18'.
chiefmike58 posted 10-30-2002 07:18 PM ET (US)     Profile for chiefmike58  Send Email to chiefmike58     
How much fuel would you think that a pair of twin Merc 2stroke 90s would consume on an 18'Outrage? Just wandering.
lhg posted 10-30-2002 07:27 PM ET (US)     Profile for lhg    
Regarding fuel consumption with twins on an 18, I get 2.75-3.00 miles to the gallon with my twin in-line 6 115HP 2-stroke carbed Mercs running about 25-30 mph.

So I would think a pair of newer 90's would average more consistanly about 3.0 mpg, but not much more.

I have found that big singles on an Outrage really don't get any better mileage than smaller twins. Using the same engine technology, it simply takes a certain amount of energy (fuel) to move a hull through the water, regardless of # of engine's & engine HP. EFI improves fuel mileage, I have found.

Peter posted 10-30-2002 08:16 PM ET (US)     Profile for Peter  Send Email to Peter     
If you don't mind overpowering, my vote is 90hp 2-stroke Yamahas. If you want to stick within the rating limit, go with Merc 75 or Yamaha 70 2-strokes. If it were me, I'd go with the Yamaha 70s. My preference would be to keep the maximum weight on the transom down around the 500lb range. The Merc 75s (detuned 90s) have generous displacement but are a bit on the heavy side.

LHG, I doubt the Merc 90 is faster than the Johnson 90. I remember reading a report (might have been Powerboat Reports) one, two or maybe three years back that compared the Johnson 90 to the Merc 90 to the Yamaha 90. My recollection is that the Johnson came out on top on speed and holeshot. I remember this because at first I was somewhat surprised by the result but then had a ride in a Montauk with the 60 degree V-4 90 Johnson and was throughly impressed with its "spunk" (damn near went over the transom of the Montauk when the owner punched the throttle from a dead stop). The Johnson has 105 cubic inch displacement versus 85 for the Merc. That's a big difference in my book and would explain why the Johnson came out on top.

Bigshot posted 10-31-2002 10:27 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
I would love to see that report because I think the 90 Yamaha performs more like 80hp. I have been on a bunch with Yammies and I know a bunch who "upgraded" from their 90 OMC and all say the same thing, especially people who ski.

Now the weird thing is that my 70 4 stroke basically pulls the same holeshot with 2 people, 4 people, 5 people, etc. Seems that speed is effected by the weight but the holeshot really isn't. WEIRD! Also I had literally 6-8" in the WHOLE boat, probably a hundred gallons or more. At 7lbs a gallon that is mucho weight. The boat was downright unstable at slow speeds if water shifted. Anyway....I got out the canal and punched it and the damn thing got on step. I KNOW that yammie would never plane with 700+lbs all in the rear.

lhg posted 10-31-2002 06:30 PM ET (US)     Profile for lhg    
Peter - Remember I only said possibly! I was basing this on reports here that have indicated a Montauk runs a little faster with a Merc 90 when compared to a Johnson. The setup could alone make a difference, either way.

I do feel strongly, however, that lack of an under cowl oil tank, is a Johnson shortcoming with Whaler's older, low storage capacity boats, all of which were designed before oil injection even existed, and hence have no specific place for external tanks. Pre-mix, 4-strokes or Merc 125 & smaller, or Yamaha 90 & smaller, seem best for Classic Whalers 13-22' under V-6 sizes.

gvisko posted 11-10-2002 08:20 PM ET (US)     Profile for gvisko  Send Email to gvisko     
Thanks everyone for such good infomation
I bought a new 2002 150hp johnson carbs for
$8,100 installed could not turn it down.
I also bought a matching 15 hp johnson
long shaft kicker. I think this wiil be a
good setup for my needs, the kicker
screw turns had to be removed to fit over transom on the out rage and motor has to
be tru bolted on staboard side . there was
no clearance on the port side with the 150.

thanks again gvisko

acseatsri posted 11-11-2002 05:39 PM ET (US)     Profile for acseatsri  Send Email to acseatsri     
Good choice. You'll be happier with the maintenance costs. Hope you got a 4S kicker so you can run off the same fuel tank as the main.

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