Cruising RPM on '88 SR 340 EC

N

norriscathy

New Member
Jan 21, 2013
60
east texas
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Does anyone know the cruising RPM's on an '88 340 EC w/ 7.4 L 300HP? I like the 340 much better than the300 WE but I'm afraid that the 7.4L would eat up a lot more fuel than the 5.7L at cruising speed. I know: Forget WOT unless you have a fuel tanker behind you!
Thanks for your help
Norris
 
norriscathy said:
Does anyone know the cruising RPM's on an '88 340 EC w/ 7.4 L 300HP? I like the 340 much better than the300 WE but I'm afraid that the 7.4L would eat up a lot more fuel than the 5.7L at cruising speed. I know: Forget WOT unless you have a fuel tanker behind you!
Thanks for your help
Norris
Click to expand...

My fuel economy numbers are slightly better than Northshore, however our 330 is a slightly smaller boat. The 7.4L engines are optional in the 330, and frankly I would not want the smaller 5.7 units. I can run 2800 rpm and 24 mph with 4 adults, full water and fuel effortlessly. I like the higher horsepower and torque which handles the boat very efficiently whether getting up on step or when docking.
Personally I believe more than just fuel economy should be considered .
 
You will do better with the big blocks.

The little 5.7s will be working their little asses off, and burning a lot of fuel, while the 7.4s will be loafing. Also, if you are serious about the late 80's 340da or ec I don't think you will find one with small blocks.

Good luck.
 
norriscathy said:
Does anyone know the cruising RPM's on an '88 340 EC w/ 7.4 L 300HP? I like the 340 much better than the300 WE but I'm afraid that the 7.4L would eat up a lot more fuel than the 5.7L at cruising speed. I know: Forget WOT unless you have a fuel tanker behind you!
Thanks for your help
Norris
Click to expand...

I am really trying to decide between a 340 EC with7.4L and a 300 EC with 5.7L. The 340 has more of everything but I'm concerned about fuel consumption. The consumption I'm getting on the 340 is exactly what the Merc web site gives at the same RPM's, which seems to be twice that of the 300 EC with 5.7L. I've narrowed my choice to one of these two boats. I really like both boats, your suggestions please.
Thanks to everyone for your input.
Norris
 
Needless to say, I'm going to be a bit biased...

We started our search off looking for 300's. We really wanted a generator and just could not find a 300 with one in decent shape. So we broadened the search out to the 340's. ZERO regrets. You are looking realistically at fuel consumption which is great but gauge that against how much time you will be using her at the dock where the fuel consumption is equal :grin:. If you find a good 300 and a good 340 and are really teetering, maybe condition, should be your primary metric.

The 80's 300 guys have there own thread so more info can be had there.

If I could make a recommendation, start a new thread - 'Late 80's 300's vs 340's' - More people would most likely dive in......

Also, "I wish I had bought a smaller boat" - I dont think I have ever heard those words uttered.


Best of luck in your quest!
 
Last edited:
northshore said:
Needless to say, I'm going to be a bit biased...

We started our search off looking for 300's. We really wanted a generator and just could not find a 300 with one in decent shape. So we broadened the search out to the 340's. ZERO regrets. You are looking realistically at fuel consumption which is great but gauge that against how much time you will be using her at the dock where the fuel consumption is equal :grin:. If you find a good 300 and a good 340 and are really teetering, maybe condition, should be your primary metric.

The 80's 300 guys have there own thread so more info can be had there.

If I could make a recommendation, start a new thread - 'Late 80's 300's vs 340's' - More people would most likely dive in......

Also, "I wish I had bought a smaller boat" - I dont think I have ever heard those words uttered.


Best of luck in your quest!
Click to expand...

See my post in your other thread. It basically agrees with most of what is said on this one. Based on your description of both boats, hands down I would go for the 340 if faced with the same choice.
I had my 87 300 Sundancer for many years and we absolutely loved it. It handled fantastically with the 5.7's and I/O's and was very fast for a boat of it's size.
300 WE's, EC's and DA's of that era are all fantastic boats with a lot of room for their size.
My boat sold overnight and I have two friends that are kicking themselves that they didn't buy it from me because it was such a great boat for it's size.Both have had smaller Sea Rays in the 22'-24' range an my 300 would have been a nice step up for them.
Back when I bought it I was primarily looking at 270's but the 300 with AC and extra room all around was a no brainer.
We loved that boat and still miss it but one of the big things we were looking for in our next boat was a generator. It would have really increased our use and comfort on that boat if we had one. There was many times we really wished we would have had one.
Extra space on a boat is always good to have too.
This time around we started out looking at 380's because we wanted the separate shower stall but after looking at a bunch of boats the 410 with diesels just offered so much more so that's what we got. We went a year or two older and spent a little more money for it than we would have for a 380 but although it's only 3 feet longer it offers a lot more room which will probably translate to us using it even more.
We came really close to closing on a 380 early last summer and were super bummed when the deal fell through but now that we have the 410 we know it all worked out for the best.
When someone asks me which is a better boat to get I always say the best boat is the one you'll use the most. Although fuel is a consideration it is only one of many factors in the expense of owning a boat. It's also the one factor you have the most control over because you can adjust those throttles anytime you want to conserve a bit.
You'll spend a lot more time on the boat with the motors not running than you will with them running.
 
My 390EC with 454 Crusaders burns 30gph @3100. My friends 340EC with 454 Mercs burns 25gph @3100. A 300 with 5.7s will burn about 20gph @3100. Given a choice I'll take my 390Ec all day given the amenities. Don't let 5gph sway your decision. As they say buy the biggest boat you can afford. It will cost you twice as much to move up in a few years.
 
hottoddie said:
My 390EC with 454 Crusaders burns 30gph @3100. My friends 340EC with 454 Mercs burns 25gph @3100. A 300 with 5.7s will burn about 20gph @3100. Given a choice I'll take my 390Ec all day given the amenities. Don't let 5gph sway your decision. As they say buy the biggest boat you can afford. It will cost you twice as much to move up in a few years.
Click to expand...

I very much agree with hottoddie. In my opinion, when looking at all the costs of boating, gas consumption is certainly not at the top of the list, although it is the most common question I am asked. Absolutely good advice to buy the biggest boat your budget can afford (considering all of the costs).
 
I sold my 300 in the fall to pick up a 89' 390EC

looks like a 10gph increase for me
 
norriscathy said:
I am really trying to decide between a 340 EC with7.4L and a 300 EC with 5.7L. The 340 has more of everything but I'm concerned about fuel consumption. The consumption I'm getting on the 340 is exactly what the Merc web site gives at the same RPM's, which seems to be twice that of the 300 EC with 5.7L. I've narrowed my choice to one of these two boats. I really like both boats, your suggestions please.
Thanks to everyone for your input.
Norris
Click to expand...

I think buying a boat in that size range based on fuel "economy" is kind of silly. They both will burn a lot of fuel and when you add up 100% of your costs for a year, the % difference is not much at all. As others have said the 5.7s will work harder and burn almost as much. Owning a boat is not a money saving kind of thing IMO. Buy the boat you want and don't get one with with the base engines in that model.
 
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