Single 7.4 vs twin 4.3's in late model 270

[joseph]

I'm shopping for a 1998-2001 270 (DA 9'2'' beam not SE 8'6" beam). These were available with a single 7.4 liter 310hp injected V8 with Bravo III drive or with twin 4.3 liter V6's with alpha drive units (either 190 or 210hp depending on model).

I'm looking for real world numbers for cruise speed, fuel consumption at cruise speed and top speed for each of these boats to help decide which to buy.

Any owners out there who can tell me what their experience is with these boats?

 

[Kevin Smith]

270 DA With 9 + Beam

Joseph,

I have a 1991 250/270 Weekender that has an overall length of 29' 6" and has an 8' 6" beam and weighs 5,600 dry. It has a 7.4 Magnum 330 hp with a Bravo II. It cruise with a full load of gas, gear, persons, etc at 3,000 RPM at about 25-30 mph, subject to wave action. I have never had it wide open, but know it will get well over 40 mph. This is the second Sea Ray of this size range with this motor and we have been very happy with the performance of both boats with the 7.4. (We found the single 5.7 motor was not enough for this size boat.)

I would highly recommend that you do not purchase the twin 4.3 option in any large boat including Sea Ray. The horsepower may look about right for the weight, but those V-6 engines don't have the muscle to push that boat and still hold up long term. If the weight is about the same, maybe you should consider the 7.4 and have the sale subject to an extensive sea trial. Do you know the dry weight and fuel capacity of the boat you are looking at? Will small block V-8s fit in that boat and still allow easy maintenance? Let me know and we can talk about this more?

Kevin Smith
Richmond VA
250/270 Weekender 7.4 330hp Bravo II

 

[Sundancer]

I've seen the 4.3 twins on an awful lot of boats! They seem to be a good and reliable package on the 25-29 foot boats. Allegedly they use less fuel than a single 454, but I don't have any first hand knowledge of this. We drove a 1991 270 (later dubbed a 290) with twin 4.3's. The engines handled the boat with ease and didn't seem to be working very hard at all. Top speed was about 35 or so around 4,800 rpms. It didn't struggle to get on plane and seemed to have adequest power. It fell off plane around 18 or 19 mph and came right back up with a twitch of throttle. It was ready to cruise and had a full complement of fuel, water, gear etc. I was impressed!

 

[saxonj]

1997 270 DA Sundancer

I have the 97' 270 with twin 4.3's. The boat handles great and the engines never seem to struggle a bit. Boat cruises at about 3200 RPM's optmimum. Fuel consumption at that rpm seems to be around 17-19GPH. I am having a floscan and full electronics package installed within the month, I will let you know the exact GPH/MPH then.

 

[gard500]

1995 SD 290

I have a 1995 Sundancer 290 with twin V-6 4.3L motors. I have only owned it for about 6 months, but it has been awesome so far. Like saxonj said, it handles very well and gets up on plane without difficulty. It cruises between 3000-3200 RPMs at around 30 MPH and has been better on fuel than I was told it would be by the previous owners. We do a lot of low RPM "cruising" and get around 9 GPH (based solely on fuel calculations between fill-ups). I suspect that number will double this summer as we start going out to the Channel Islands more.

Saxonj, I am looking forward to hearing your floscan results. I too am looking to upgrade my electronics and add a floscan and am interested in the package that you put together.

 

[saxonj]

270 Sundancer 1997 twin 4.3's

I just had a floscan installed. 3200 RPM 29Knts at 6.5 GPH per motor.

 

[Kevin Smith]

Twin 4.3s Mercs

I am very impressed by the that kind of fuel efficiency. Never would have thought is was that good. Thanks for taking the time to post the results.

Kevin Smith
Richmond VA

PS Did met a guy with a 2003 290 Sundancer with 4.3 twins are our marina the other day and his boat is for sale. He had just put new motors in it. He said the dealer told him they failed due to water getting into the engines and said it was related to the condition of the flappers, the height of the risers and the low mounting position of the engines.

 

[saxonj]

Floscan twincsan for IO/ Internet price is 485.00. Installation cost was 695.00, a very proffessional job done by Andy Scevelli 727 638 8484

 

[netboy]

Twins vs Single

Hi, a couple of comments about twins. They DOUBLE your maintenance, and they fill up your engine compartment so that working on them is tight.

When are twins a good idea? When you need to be sure you can get back to port under power. If you mostly use the boat on a lake or other places where there are lots of other boaters, if your engine won't run you can probably get a tow. But if you deep sea fish, running out many miles to places where there are not many other boats, having twin engines is a real saftey plus.

Regarding fuel economy, in the general case there probably will not be a huge difference. Same overall power required for any speed. Two small engines and outdrives probably weigh a bit more than a single big block.

I have owned both. For my current needs I have a big block single, and plan to buy a 10hp outboard kicker engine for when I take it out in the ocean for emergencies.

Twins make especially good sense for BIG boats (12' beam and larger), where you need more power than most singles can provide, and there is plenty of room in the engine compartment to get down between the engines and work on them in relative comfort.

Just my 2 cents worth.....