Motor lb range I should be factoring on an 84 20SF

[mbo_1971]

Recently picked up an '84 20SF hull (thanks Rex) and am looking for power. Others have mentioned the max HP rating was 175, but being fairly new, im wondering what kind of weight limit that means for new (used) power. I was thinking of hanging a 200 HPDI, on her, but wondering what others have done and issues I should be looking out for. Thanks.

matt

[caper]

I had a Yamaha 130 a stroke on my '75 20SF - 360 lbs. or so and the weight was about right - no wet feet - I am moving to a Johnson 175 2 stroke at about 390 lbs. I believe I can keep things the way they were by moving the battery and the oil tank under the console - still dry feet. It seems to me that anything much over 400 lbs. would be too heavy with the standard Seacraft scuppers.

[TUGBOAT]

Had a 200 Mariner on My '83 20 MA when I purchased it. Faaaassssssst! I now have a 150 Merc. I would go back to a 200 or 175.The 150 is actually heavier I thinks ?
Mo Metal !
Scream'n reels'

[tommytuna]

Suzuki 300-Hp Four Stroke
By Staff (more by this author)
Thu, Apr 13, 2006

It was only a matter of time, we suppose. But we've consequently learned to never say never. Not so long ago, the prevailing wisdom insisted that the laws of physics would never allow a four-stroke outboard to exceed 250 horses. It would be too big and bulky for transoms. Well, boat and transom redesigns, combined with advanced engineering and mechanical and electronic innovations, have upped the ante to the point that current wisdom knows no limitations. The former nay-sayers just shrug when someone suggests a 400-hp outboard.

If anyone can do it, it's Suzuki. At the recent Miami International Boat Show, American Suzuki Marine introduced the world's first 300-hp, V-6, four-stroke outboard motor. In his short speech, Suzuki Marine's marketing director Larry Vandiver said, "This should leave no doubt about Suzuki's commitment to push the envelope in four-stroke outboard power and performance."

The very first 300-hp two-stroke outboard qualified as a dedicated racing product. Having fished a number of them, we can vouch that they despised trolling speed so much that after trolling for several hours, you stood little chance of getting up onto plane before visiting a mechanic. Not so with Suzuki's four-stroke.

Available in both 25- and 30-inch shaft lengths, Suzuki's DF300 should elevate the company's reputation for superstrong, high-end-of-the-power-band ratings, as ever-lengthening offshore fishing boats start supplying transoms for more big-block power. Who knows? Perhaps we'll even get away from triple-engine installations in lieu of a pair of 300s.

The DF300 carries over some of the proven technology found in Suzuki's previous models, as well as features new and unique. For example, from previous models, Suzuki has kept dual overhead camshaft and 32-valve powerhead, variable valve time, multipoint electronic fuel injection, gear-driven timing chain and California Air Resources Board Ultra-Low emissions rating. However, the company created an entirely new, sleeker lower unit to handle the increased horsepower's higher speeds, but retained the successful two-stage reduction gear that allows Suzuki to turn props with higher pitch than its other engines.

Another truly appreciated feature — electronic throttle and shift controls — makes rigging a boat easier and operating it like driving on a silk highway. This system affords you several other new advantages, too: Want a second control station? No problem — just plug in a single wire. You need only one key to control any number of engines, and the key can be inside the cabin or console if you wish. And should you opt for a triple-engine installation, you don't need triple-throttle/shift controls. Underway at speed, all three engines respond to a single throttle lever. At maneuvering speeds, the two outboard engines respond to two levers while the center engine idles in neutral. We've found this to be an excellent safety feature in addition to a convenience. When maneuvering in close quarters, we always have to look down to assure that we're moving the correct lever when using triple controls. Use of dual controls more closely corresponds to an autonomic function like your heart beating or lungs breathing. With twins, we can maneuver without thinking.

Historically, Suzuki's biggest shortcoming has had nothing to do with its superb products, but rather with a smaller-than-the-competition dealer/service network. In recent years, Suzuki has aggressively entered the OEM marketplace, increasing the number of factory transoms, as well as independent dealers and service technicians.

There's a reason why you see so many Suzuki outboards used in oil-drilling operations, marine construction and commercial diving companies where a down day means a serious financial loss. Suzuki's reputation for reliability day after day buys the loyalty of those marine enterprises.

Sport Fishing is reporting this news without the 300's specifications. At press time, Suzuki had not released them. For more information, contact Suzuki at 800-247-4704 or visit www.suzukimarine.com. — Ed.

[Blue_Heron]

Hey Matt,
I've got a 1999 Merc Carbed 200 on my '83 20SF. She'll run around 50 mph WOT with a light load, around 45 with a full load of gear, crew, and fuel, but I'm still experimenting with props. She cruises at about 33 at 4200 rpm. All speeds measured on GPS.

I checked my fuel economy on my first offshore trip and went 82 miles on 30 gallons of fuel. That works out to 2.73 mpg, or about .91 mp$ at today's gas price. The only thing I would change would be to go with a fuel injected motor to improve the fuel economy.

The motor weighs about 400lb. With a full load, I have to keep the plugs in the scuppers to avoid wet feet. Had to gasket the bottom board on the splash well, too. The cockpit drains just fine at the dock with nobody aboard.
Dave

[HatTrick]

I have a 86 20SF with a 2005 yamaha 4-stroke 150. The motor with the 25" leg is supposed to weigh 475 lbs. so I pulled out the old oil reservoir and moved the two batteries under the console. It drains fine at the dock but i often put in the scupper plugs when fishing in case a few people stand in the corner. The motor is probably at the limit in terms of weight but I love this motor! Quiet, powerful, and very easy on fuel.

[mbo_1971]

great info - thanks much! I was hoping to find a Yamadog 200 HPDI somewhere. I know that is a little more tha 400, but if i can more the batteries and oil under the console, that might help a little. Thanks again.

[Bigshrimpin]

Just like SeaCrafts . . . Newer is not always better.

As other folks have mentioned. The older Chrome Bore Carb Merc/Mariner 2.4L 200hp motta's around 1985,86,87,88 are great. They're light 360lbs, Fuel Efficent 3mpg+ . . . (cruise 4k rpm . . . 30 - 35mph depending on the prop) and You can pick them up for less than 2k. Parts a dirt cheap, they're easy to work on and once you yank the oil injection they'll go for a long time.

You can also modify them to get a lot more than 200hp:
http://www.byuboyz.com/modules.php?n...warticle&id=45

[mbo_1971]

You can also modify them to get a lot more than 200hp:
http://www.byuboyz.com/modules.php?n...warticle&id=45

i have no idea what any of that means!

[Bigshrimpin]

Don't worry . . . It's written by Spidie's Couz'in.


It covers many of the mercury 2.4L racing tricks to improve airflow and cooling (i.e. generate HP) through the blackmax motors.