repower

[FlyDoc]

Blackfin,
Prior to buying my 2003 SeaCraft Master Angler I looked at two identical SC20s, one with the Yamaha 150 HPDI and the other was the 4 stroke. It is a little known fact that the two 25 inch shaft engines weigh exactly the same. The big difference is that the 4 stroke is actually a smaller 4 cylinder engine and the 2 stroke is a six cylinder. The six which is what I actually picked for my boat. The HPDI makes more low end torque. I was told by the Yamaha Dealers locally that the 4 Stroke was actually designed to be used as a twin in applications such as the Pathfinder 23 Offshore. They seemed hesitant to use it as a single.
Chris

[warthog5]

The DF-140 Suzuki is 410lbs for 20in. & 420lbs for 25in.
http://www.suzukimarine.com/sr04/df1..._and_specs.php

[Mark]

The Suzuki 140 4-stroke will push a SeaCraft 20 (with a full 75 gallon tank and t-top) along between 42-44mph.

Not real sure what is meant by "enough" when used in conjunction with engine sizes, but you see SC20's for sale on boattrader with 90hp engines on them. Mine had a 130 on it when I bought it and it was VERY "enough". I suspect that a 115hp, at 15hp less, would get you up on plane and the fish would still bite. However, if speed is important, you should probably consider as much horse power as you can afford.

[Finster]

A Suzuki 115 on my Aquasport does 38 mph with two guys, a full tank and beer.......
And the Aquasport specs out at 2300lbs dry which is 800lbs. more than the SC 20 at 1500.
I have no dought that the 115 will preform well on the SC 20 when I swap out the motors.

[Dunk]

Blackfin, this is my first post here. Jason asked me to add what I can...

That 150 Yams is a butt kicker from what I've seen and it's probably right at the 10% max(NMMA)165hp at the prop.. But I'm not a 4 stroke guy nor am I fan of Yamaha's. Although that Yam is the one I would recommend if you are dead set on a 4 stroke. That 175 Merc on that boat was the perfect power. Light and plenty of guts. But remember in 1976 the only V6 on the market was the 200hp Johnson and that was it's first year. So, that 20ft seacraft was designed for 300lb V4 OMC or 6 cylinder inline Mercs.. If I was repowering that 20ft Seacraft I'd be looking at a 175 Evinrude DFI. That 150 Yam is a strong engine, but it won't stay with a 150/175 Rude for the simple fact the Rudes are V blocks and produce more lower end torque. It's safe bet that Bomb will offer the 7yr warranties for the boat show season. The last two years it's been Jan 15 till Apr 15. Anyway you cut it Seacraft's are heavy deep vee's and need horsepower to move them. A 175 Evinrude comes in as close to that 175 Merc weight wise as you can get at 427lbs for a 25" engine. Somehow I just don't see a 140 Suzy moving that boat at 40mph+. Even if it would once you put 3-4 guys on it and gear/fuel the party is going to cave in fast. Getting a load like that out of the hole is a V6 job. Even a 135hp Evinrude will run circles around a 4 stroke 4 cylinder 140hp engine and especially out of the hole. Even if you are not looking for top end you want an engine that doesn't need to fight to get the boat on plane.

There's a guy around here with a 225 Johnson on a 20ft. You guy's are right....it's way to much weight. The SOB will run 55mph, but it looks half sunk sitting in the water. I've also got a buddy with a 75' 20ft with an 87' 120hp V4 Evinrude(looper). It's nice setup. The engine weighs 360lbs and it will run 35mph with 3 big guy's in it..cruise at 26-28. In any more than 2-3ft seas you can't run more than 20-22 anyway. The 135 Rude DFI's are rated 148hp at the prop according the Bass&Walleye magazine test. Everyone's 150 is 165 at the prop or they wouldn't survive the bassboat circuit and you can figure the Bombs 175 at about 190 at the prop. Everything we're talking about here is about a dead heat on fuel consumption at cruising speeds.

[Trayder]

Ah-

that did not take long.

Dunk- welcome to the forum thank you for sharing your info as this post is excatly the great type of info that helps us all out a ton.

By the way I have a 140 suzuki on my 20 CC unlike non-modified 20's I think my boat weighs in at 1300lbs un rigged. Even then I do not see 40+ with more than 1 other person on the boat.

I was going to repower with the 150 Yamaha this past spring however do to weight and the cost difference I stayed as is, but that 150 is much more powerful than my 140 Suzuki.

[Scott]

HOW COOL !!!

Dunk ...Welcome to the site!!!

Jason has come up with an incredible site ...with exceptional members….
Tremendous people here … all sharing a common link through these boats.

Thanks for sharing with us ... we are bound to learn lots.

[Capt Chuck]

Even then I do not see 40+ with more than 1 other person on the boat.

That speed reduction wouldn't be because you had a fat azz Fla guy with eel slim on his hands hanging on for dear life on the transom crossing Buzzards bay

BTW: Welcome Dunk, with 47 years in the business it apears you might be in my age group [img]/images/graemlins/tongue.gif[/img]

[Finster]

Jason, I wouldn't expect to see numbers much more then that with the 140. Like I said my numbers are pretty good with the 115 and it's got a nice cruise of 24mph+- at 4000, but for that boat I don't think I would want too much more due to the fact you'll get beat to death in light chop at higher speeds. But the SC displace's much more water than the Aquasport so that may offset the 800lb. difference.
Scotts been in the Aquasport plenty, and we've had simular conversations on the subject.


Oh yeah, Dunk welcome aboard. Don't embarrass us too much. [img]/images/graemlins/grin.gif[/img]

[Bigshrimpin]

Just looking through the NADA outboard section and I couldn't help but notice the weight differences b/w old and new power.

For example:

The 1975 straight 6 Mercury 150's weighed in at 275lbs.
The 1978 Mercury v6 200hp weighs 330lbs.
The 1987 Mercury v6 200hp weighs 363lbs.
The 2003 Mercury v6 200hp wieghs 406lbs.
the 2003 mercury v6 200hp Optimax weighs 512lbs.
and 2005 Mercury v6 200hp verado is 650lbs.

http://www.nadaguides.com/Values/Val...ode=MR&Type=OB

After 30 years of time . . . Shouldn't outboard companies have been able to "make progress" and refine these engines to make them lighter and smaller?

I'd be willing to bet that a 1978 merc v6 200 (330lbs) is more efficent than a 2005 200hp verado (650lbs ***twice the weight***of the 1978 engine) bolted on the back of a 20ft seacraft.