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Author Topic:   Cost Savings of Fuel Efficient Motors
cc13 posted 07-21-2004 04:27 PM ET (US)   Profile for cc13   Send Email to cc13  
Is my math right? If I cruise a 90-HP 2-stroke at 4.5-GPH and I cruise a similar 4-stroke at 3-GPH, then I conserve 1.5 gallons per hour. At $1.80 per gallon, a 4-stroke saves $2.70 per hour of use. If the 4-stroke costs $1,000 to $1,500 more than the 2-stroke, it takes between 370 to 555 hours of use to recoup the initial outlay. Isn't the 2-stroke more cost effective?
Buckda posted 07-21-2004 04:36 PM ET (US)     Profile for Buckda  Send Email to Buckda     
Your math looks right, but you've left out a couple of factors:

Add the cost of 2-stroke oil
Add the cost of carburetor adjustments
Add the cost of 4-stroke oil changes and spark plugs.

I think the 2-stroke still comes out ahead in terms of cost effectiveness, however, there are the benefits of smoke-free, quiet operation of the 4-stroke engines, environmental friendliness, no need to handle 2-stroke oil, and other "intangibles" that make these new technology motors worth it to many people.

You have to calculate these benefits in your mind to come up with a true determination of which motor provides the greater benefit:cost ratio.



Florida15 posted 07-21-2004 04:36 PM ET (US)     Profile for Florida15  Send Email to Florida15     
I think a lot of the 4-strokers buy for more than just fuel savings, like being quiet and clean.
Personally, I would have to have a fairly quick payback to buy one but then I kind of like the sound of a two stroke.
2manyboats posted 07-21-2004 04:52 PM ET (US)     Profile for 2manyboats  Send Email to 2manyboats     
Not sure about fuel usage , but at cruising speed 2-stroke will use close to 40 gallons of oil at 4.5 GPH in 500 hours. The 4 stroke will use 5 filters and 20 quarts of oil.
rtk posted 07-21-2004 04:53 PM ET (US)     Profile for rtk  Send Email to rtk     
I went through the same math when I was choosing an engine for my re-power. I guess it would depend on how many hours you put on the boat a year and how long you expect to keep the boat.

If you plan on keeping the engine a long time and will put a lot of hours on it, the four-stroke would seem to save you money over the long term. Initial investment and short term or low hour use the two-stroke seems to be a more economical choice.

The other consideration between two-stroke and four-stroke is oil, smoke, engine noise, and environmental concerns. For some the extra dollars for the four-stroke may be justified by no smoke, less noise and a more environmentally friendly motor, even ignoring the cost savings from better fuel economy.

I chose the two-stroke strictly based on the price of the motor. It would have cost me about $4,000 to $6,000 more to go with a 225-HP to 250-HP four-stroke. I don't know how long I will own the boat--may move up in size--so I did not want to make the investment in the four-stroke. I went for the biggest bang for my buck for horsepower and a good local dealer to service it. Those four-strokes sure are nice, though.


rtk posted 07-21-2004 05:22 PM ET (US)     Profile for rtk  Send Email to rtk     
And yes florida15, there is something special about the growl of my Mercury 250 EFI V6 : ). The thing sounds like a stock car when I fire it up. Although I don't think the person who stays in his sailboat on the weekend in the slip next to me appreciates it as much as I do at 5:00AM when I head out to fish.


Sal DiMercurio posted 07-21-2004 06:54 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
There sure aren't many 2-strokes that still have carbs.
The DFI 2 strokes.
CC13, I really don't think there is a DFI 2-stroke that would even use 5 gallons of oil in 500 hours.
I've got 1,100 hours on my DFI and I haven't bought 18 gallons of oil, maybe less.
The DFI's also match the 4-strokes and in many cases get better fuel economy than the big 4-strokes.
Smoke? I haven't seen "ANY" smoke in the last 4 years since I bought the DFI.
rtk posted 07-21-2004 08:56 PM ET (US)     Profile for rtk  Send Email to rtk     
You are right Sal, the DFI two-strokes are about as efficient as the four strokes and do not smoke like the EFI/Carb two-strokes. I found the DFI two-stroke prices are very similar to the four-stroke, I typically put them in the same category as the four-strokes for efficiency and price.

Good point.


Moe posted 07-21-2004 10:03 PM ET (US)     Profile for Moe  Send Email to Moe     
Your math makes the same mistake most folks do when they calculate that a diesel engine will never pay for itself, that is, they forget the added trade-in/resale value that will be returned.

And with diesels, they usually use window-sticker MSRP for their caculations, rather than the closer to dealer invoice price savvy shoppers pay.

In the case of the diesel option, the added value at trade-in/resale can be much of the dealer-invoice price. That may already be the case with four-strokes, and will probably increase once carbed two-strokes go out of production.

jimh posted 07-21-2004 10:09 PM ET (US)     Profile for jimh  Send Email to jimh     
You will not have to compute these differential costs much longer. In a few months only the low-emission engines will be available to purchase new.
Clark Roberts posted 07-21-2004 10:51 PM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
I wonder what a valve job will cost me on my dual overhead cam, four valve per cylinder four stroke? My mechanic friend says there is no scheduled valve adjustment nor is it possible to adjust valves. AND valves don't last forever and sooner or later need grinding and reseating. I was in a Yamaha dealer shop today and the work bench was covered with maybe six power heads in various states of disaster and on examination of several I noticed very badly burned valves and messed up heads... big $$$$$$ is my guess. I will keep my fingers crossed... Clark... Spruce Creek Navy
jimh posted 07-22-2004 08:07 AM ET (US)     Profile for jimh  Send Email to jimh     
[Changed TOPIC; was "Is my math right?"]
Jarhead posted 07-22-2004 08:51 AM ET (US)     Profile for Jarhead  Send Email to Jarhead     
Hmmmm, another 2 stroke-4 stroke volley. Okay I'll play. :)

Tuesday the 20th I stopped off at the boat ramp in Fanning Springs to dunk my 160 Dauntless/trailer and run my 115hp 4 stroke Mercury in the fresh water of the Suwannee river after a day of fishing on the Gulf.

As I was about to board the boat, after backing into the water, another rig came by to also take advantage of the nice fresh water double ramp.

The other rig backs down the adjacent ramp with one of the party aboard the boat. I ask the guy in the boat, as I start my Merc. and it runs quietly, if they had any luck, where they fished ect. He answers and we talk a little until he starts up his 2 smoke (on the third attempt). I doubt if a bullhorn would have been enough to carry over the roar of that 150 at fast idle. And don't you know, the smoke drifted straight over to me!!

When you hear someone say "I'll never go back" is there a doubt which type engine they're talking about? To my way of thinking things like this need to be entered into the equation of worth.

My .02 :)

Legobusier posted 07-22-2004 09:07 AM ET (US)     Profile for Legobusier  Send Email to Legobusier     
I agree with Jarhead. While your math may be correct, there are several different things that effect "value" in this equation.

I'd venture to bet you own a Whaler because of many of those similar factors - after all, dollars and cents wise a Whaler's certainly not cheap.

cc13 posted 07-22-2004 03:16 PM ET (US)     Profile for cc13  Send Email to cc13     
Actually I own a whaler because: I can anchor it in the surf for days and nights at a time and not worry about a storm or squall sinking it; I pull the plug and it drains all rainwater; if it takes one over the bow, it drains that too; I don't have to worry about the functioning of batteries, bilge pumps, thru hulls, etc.; relatively speaking, it's light and rides high in the water; if my family goes out and gets in trouble, I know the hull won't fail them; I can fish in 1-2 feet or as deep as I please; it will never be functionally obsolete; at its most basic level, the most important function of a boat is to float; I can pamper it or abuse it and it keeps on smiling.
Presently, I prefer a 2 stroke because of many of the same considerations.
Bigshot posted 07-22-2004 03:23 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Being I currently own both....I am appalled at myself when I start my 225 and probaly kill all the fish in my canal from the smoke that pours out of that thing.

500 hours is about 2-3 years for how much do I save in the next 500-1500 hours? My 90 OMC burned 6gph @ 4k. My 90 Yamaha burned 4.5hph but they are more like 80hp. My 70 Suzuki burns about 2.5gph at cruise.

Using 90hp OMC vs a 90hp 4 stroke I get this: 3gph is still half of what the 90 OMC burned and she sucked down $3 of oil per 6 gal tank as well. Now if I burn 1/2 the gas and no oil...I am saving about $8-9 per hour which makes it about 150-200 hours or one season for me.

When I blew a piston last X-Mas, I was considering a new engine and the difference between $9500 and $12,500 was pushing me towards a 225 Ficht for the extra $3k because I KNEW I would regret buying another conventional 2 stroke. Instead I had the one rebuilt for about $3k and even though I have $10k still in my pocket...I kinda regret not getting a modern motor. For a 115 or under, $1000-1500 is $$$ in the bank down the road when you go for the DFI or 4stroke.

Bigshot posted 07-22-2004 03:44 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
When you get into the higher HP engines, burning 8gph vs 13 at cruise is a HUGE savings and extends your range considerably. I know I would use the big boat more often if she did not suck down gas faster than I can pour it in. A one hour trip each way to my favorite drinking spot is a $50 day with the 225. It is about $10 with the Whaler. It would only be about $30 if I had a 4 stroke 225 and hence I might sell the small I am getting way ahead of myself here.
cc13 posted 07-22-2004 07:58 PM ET (US)     Profile for cc13  Send Email to cc13     
If I ever get a boat big enough to need 200+ to get to the drinking grounds, I think your reasoning has serious merit.
JohnJ80 posted 07-22-2004 11:48 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
Also, since a 4 stroke (and in this case, I include DFI engines) uses less gas, you get more out of the same tank you carry on board. You 'buy' back storage space.

Clark Roberts posted 07-23-2004 07:49 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
If you trade a car that gets 15 mpg for one that gets 30mpg do you save any money on fuel? "Robert's law of the conservation of cash" states that you will not save any money on fuel, you will simply drive twice as far or more! Now, there are some corrollaries (sp?) to this natural law which says that building more roads does not reduce traffic but only makes it easier to drive thus creating more traffic... etc. If you really want to reduce traffic, try removing roads! Blah, blah, blah... but seriously, haveing had many, many engines (including DFI and 4 strokers... I had a 4 stroke Lauson 7 1/2 aircooled power head and water cooled exhaust baffle back in 1953) I like the "driveability" aspects of the modern 4 stroke ( least at idle, smoothness, ease of least with EFI,) above the fuel savings... increased range is more important to me than cost saving on a gal. of fuel.... But I still love my two strokes. As in the case of automobiles and motorcycles, we were forced into more advanced engines by the govt. and bingo we got better products so maybe we will all look back and be thankful that the private sector responded to regulation with advanced products. But, we pay for it don't we!? Happy Whalin'... Clark... Spruce Creek Navy
Larry McNerney posted 12-06-2005 03:56 PM ET (US)     Profile for Larry McNerney  Send Email to Larry McNerney     
Just wanted to add my 2 cents.

I recently repowered and swapped my 225 2 stroke carb for a 250 4 stroke DFI. Wow what a difference. I have a one hour run to my fishing grounds so I notice a huge difference in noise and fuel efficiency. I use less than half the fuel I used to. My normal outing used to cost me ($100-$120) 50-60 gallons of fuel. Now I burn ($40-$50) 20-25 gallons even with a little extra muscle. With gas prices now over $2 this savings is compounding.

It cost me extra to opt for the 4 stroke but I figure I paid for the quiet ride. The fuel savings is a bonus. I paid cash for my motor so i am not paying interest on a loan, but If I had a payment I would still opt for the 4 stroke. I think there is a personal break even point for each individual user depending on how many hours you run your motor each year. I considered buying a 2 stroke DFI because the fuel comparisons were similar. I am glad I didn't for the noise reduction alone.

jimh posted 12-06-2005 06:28 PM ET (US)     Profile for jimh  Send Email to jimh     
Below is a link to a spreadsheet which will provide a basis for computing fuel cost savings as a way to recoup the capital expense of a new motor. It assumes a more reasonable 30-percent improvement in fuel economy, as opposed to the 150-percent (or more than double, almost three-fold) improvement cited above. If real world results always provided 150-percent improvements in fuel economy, there would be a five year backlog of orders for new motors.

Engine Cost Analysis Spreadsheet

The spreadsheet is a development from a discussion begun in:

New Engine: When to Buy

boatdryver posted 12-06-2005 07:06 PM ET (US)     Profile for boatdryver  Send Email to boatdryver     
For me, I don't get as far as all those calculations on operating costs or (shame on me) the environmental concerns. I just like to troll and cruise around sightseeing at idle with no smoke or noise, and like the idea of a 2000+hour useful life.
lavieve posted 12-06-2005 08:53 PM ET (US)     Profile for lavieve  Send Email to lavieve     
All of this is very interesting. However,I have learned not to poke too deeply into the cost of boating and fishing. As long as the bride doesn't object too much, there is food on the table for the family and a roof over their head, I prefer to eyeball the cost. How can you put a price on something you really enjoy. For those who believe in expensing these costs out, the next question is how much does it cost per pound of fish you put on the table. I am sure that its cheaper at the fish market, but who cares. Relaxing, enjoying the experiece and forgetting the stress of everyday life is priceless.
jimh posted 12-06-2005 09:17 PM ET (US)     Profile for jimh  Send Email to jimh     
See the threads mentioned above for more factual analysis. I think they'll make a better place for more discussion on this general topic.

[Thread Closed after being revived from five months of dormancy.]

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