repower
 

Hi everyone,

I just bought a 76 20 ft. cc, with a blown 175 Merc Black Max. The boat appears to be in great shape, the floor is very solid,gas tank was replaced in 91, the transom seems to be very solid.( I guess I wont know for sure until I take the old motor off). My question is does anyone know the weight of the Merc Black Max, I'm cosidering putting a Yamaha 150 four stroke on the boat but I'm concerned about the weight of the 2 motors being drastically different.
Also is there any other way to check my transom prior to removing the motor?
Thanks alot,Blackfin

Re: repower
 

Your motor weighs 400-450 lbs.My boats in the shop having a 225 hp. optimax installed. I've got a 2002 200 hp. EFi for sale. Runs great, I'm in the Merc. pro program so I update my power every 2 years.

Re: repower
 

A 1994 Merc 150 carb 20" motor weighs 406 lbs, according to an old brochure I have.

Re: repower
 

You have email

Re: repower
 

If the floor is original (height) and you don't intend to raise it, I would put the lightest engine I could find on there. A 130 Yamaha Saltwater Series 2-stroke will push those boats pretty good - it's what mine had before the redo and they aren't real heavy.

A 150 four stroke Yamaha, for the 20" shaft, weighs 466#s. If you have a 25" transom, that figure goes up in weight.

If you do leave the floor where it is, and put a four stroke engine on there in that weight range, you WILL need plugs in your scuppers and it will not be a self bailing boat except when underway. Sadly, I know this from experience [img]/images/graemlins/frown.gif[/img]

Re: repower
 

edsmarinesuperstore.com has a special on 150 yamaha 2004 2 strokes $6,700

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Mako 23, check your P.M.

Re: repower
 

A friend put a 225 opti on his 20,BIIIGGG mistake. Like Mark said plugs have to be in all the time when anchored or docked. In my opinion I would not put anything back there that would hurt the self bailing.

Re: repower
 

Thanks guys, I don't want to screw around with th self bailing system, I'm going to look into a two stroke, or possibly the four stroke suzuki 140 it's supposed to be pretty light. Would a 115 be enough H.P. for the 20 C.C.? I've heard mixed reviews.
Blackfin

Re: repower
 

115 would not be enough, stick with 2 strokes for weight and there is not much adavantage to 4's with the new ones, 140-150 is fine, I would think you would rarely find an opportunity to open up a 200 or 225

Re: repower
 

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

Re: repower
 

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

Re: repower
 

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.

Re: repower
 

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.

Re: repower
 

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.

Re: repower
 

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.

Re: repower
 

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.

Re: repower
 

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 http://www.click-smilies.de/sammlung...smiley-040.gif

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

Re: repower
 

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]

Old vs New engine weight.
 

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.

Re: Old vs New engine weight.
 

The '78 200 may or may not be more efficient than the Verado,but at least the boat would be floating.

Re: Old vs New engine weight.
 

Wow, in 30 years they have managed to more than double the weight and the price!

Re: Old vs New engine weight.
 

In 1977 I bought a 1976 175 Merc. If memory serves me right 76 was the first yesr for the V6 Black Max.The motor was a new in the box left over. I paid $2700 installed.

Re: Old vs New engine weight.
 

Verado is also a straight six, which is also somewhat ironic.

Re: repower
 

DUNK THANKS FOR YOUR POST ON THIS TOPIC I FOUND IT TO BE VERY INFORMATIVE [img]/images/graemlins/smile.gif[/img]. MAYBY YOU CAN HELP ME OUT,I AM ONE OF THE SEVERAL GUYS THAT HAS GOT A 225HP JOHNSON HUNG ON MY 1988 20'SC IT'S A 1992 MOTOR. WHEN I ORIGINALLY PURCHASED THE BOAT BEING OVERPOWERED WAS ONE OF MY CONCERNS. I DID SOME RESEARCH AND FOUND OUT THAT IF I WAS TO GO DOWN TO A 175HP I WOULD ONLY HAVE DROPPED ABOUT 60LBS, SO I DECIDED TO RUN HER AND SEE WHAT KIND OF PERFORMANCE I WOULD GET. I HAVE TO SAY THAT UNTIL NOW I HAVE HAD NO PROBLEMS, I FEEL SHE SITS REALLY NICE ON THE WATER & SHE DOSENT SEEM TO BE TAIL HEAVY (I WILL POST PICS TO GET SOME OTHER OPINIONS) ATER READING THIS POST I SUDDENY FOUND MYSELF WITH DOUBT AGAIN. [img]/images/graemlins/confused.gif[/img] AS ALWAYS ANY AND ALL OPINIONS ARE GREATLY APPRECIATED. [img]/images/graemlins/wink.gif[/img]

Re: repower
 

Noahsark, I wouldnt be to worried if youve been running the boat and dont have any stern issues. Ive seen quite a few 20s with 225s

Re: Old vs New engine weight.
 

I just went on a sea trial in a (72)20' CC with a 150 Yamaha 4 stroke. No problems what so ever with water coming in. The 4 stroke has a much different power band though. It didn't seem quite right too me. I have a Johnson 200 on my 20' with no problems.

Re: repower
 

I have a 1986 18' Seacraft with a 1991 Mercury 200 offshore engine on it. The engine was on the boat when I purchased it and had a seized piston due to an oil injection problem. I too looked long and hard at re-powering with a smaller engine. However, I found that some of the smaller engines (175, 150) are actually HEAVIER than the 200. I don't remember the exact weights, but I spent a lot of time on the NADA site. Someone also told me that the 200 v6 block is the same one used on mercury's 150 and 175. The only difference is the bore, and some electrical. Anyway, I decided to re-build the engine myself and removed the old oil injection system. It is now a pre-mix engine and has been running strong for about 3 years. While I will agree that the horsepower may be a little much, the weight does not seem to be a problem. I rarely drive the boat more than a good cruise speed, but it is nice to have the extra power if you need it....Toadfish

Re: repower
 

The 20' Seafari is even heavier than the CC, and will run just fine with a 115. My first Seafari was a 1973, 1830 lbs hull weight, dealer equipped with a '74 115 Mercury. Cruise was about 24-25 mph, top speed was about 29-30. I repowered with a '77 1500XS which gave me a cruise of 34-35, and a top speed of 45-46 mph.
My current Seafari is a '72, hull weight is 1870 lbs, and I got it with a 1972 Chrysler 120 hp. It planed easily, cruised at 22-23 mph, and had a top speed of 26 mph. I installed a 1991 Mercury 150 XR4, with the big gearcase and a Bob's nosecone. Top Speed light on fuel with just me is 46 kts on the ol' GPS, which I think is about 51 mph. Cruise is 34-35 mph, just like the 1500 XS. I have a higher top end with the V6, but not significantly higher. The real beneift is that the XR4 is better on fuel.