Repair Cost and Fuel Economy of Outboard Engines Using Carburetors, Port Fuel Injection, and Direct Fuel Injection

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Author Topic:   Repair Cost and Fuel Economy of Outboard Engines Using Carburetors, Port Fuel Injection, and Direct Fuel Injection

TommyWhaler posted 09-16-2011 05:29 PM ET (US)
A reputable outboard mechanic that sells used motors--anything you want--says he wouldn't have [an ouboard engine that used port fuel injection or direct fuel injection]--DFI or EFI--unless [the outboard engine] was new and under warranty. So, if you have [a new outboard engine that uses port fuel injection or direct fuel injection] and [your outboard engine] is under warranty, this thread is not for you. [Huh?--jimh.] [The mechanic's] reasoning is [repair of EFI or DFI engines] is almost five-times more expensive than [repair of a] carburetor motor. In addition, he says that the fuel economy on the c.1995 and newer outboard engines is not that far off the economy of DFI and EFI. What say you?
contender posted 09-16-2011 06:41 PM ET (US)
Do not know about the fuel economy, but to work on the carburetors I do not think they can be any simpler compared to the other type of induction. A mechanic should be able to take a carburetor apart, clean it, and assemble it (with all the parts) properly, no special tools are needed.
MATTANZA posted 09-17-2011 04:51 AM ET (US)
Does this mechanic have a carburetor in his car? Or fuel injection? I was a marine mechanic for over 10 years, and off-and-on for over 20. I'd take DFI or EFI over carburetors any day. My OptiMax is way more dependable than my past motors of experience. In my OUTRAGE 15 with 225-HP OptiMax get 3-MPG at 20-nautical-miles-per-hour. I'd be lucky to get 1.5-MPG with carburetors. Does your mechanic own a boat? If so. what make, yearm and power? That will tell you about the mechanic. Some of the best and smartest mechanics that I've known have never owned boats, so their opinions may not be based on user experience.
jimh posted 09-17-2011 10:09 AM ET (US)
I was going to respond, but I believe that I am disqualified by the criterion set forth in the initial article because I own an outboard engine with direct fuel injection that is under warranty. However, I don't have any plans to sell it and get an outboard with carburetors, if that information is useful to the discussion.
jimh posted 09-17-2011 10:21 AM ET (US)
I don't see much difference in fuel economy between outboard engines using a carburetor and outboard engines using simple port fuel injection schemes, particularly older outboard engines which lack sophisticated engine control systems and run in open loop modes of control. I will give a nod to the simple port fuel injection engines as being easier to start if the operator does not know how to read the owner's manual, easier to start if the temperature is very low, and easier to start if the operator never primes the fuel system. But in the moderate temperatures and sea level elevation that most outboard engines are used, I do not see an overwhelming advantage to port fuel injection over carburetors, and particularly for more modern carburetor engines with smarter control systems and operated by someone who read the owner's manual.
Perhaps the best port fuel injection engine made was the Yamaha Ox66 series. Those engines had a closed-loop modern control system. They probably offered improved performance and fuel economy compared to simpler systems on competitors' motors.
The fuel economy of direct-injection engine is much improved compared to other methods, particularly in two-cycle engines where direct-injection makes an enormous improvement in fuel economy.
DeeVee posted 09-17-2011 10:59 AM ET (US)
I recently repowered from a 1992 200 Suzuki carburetor engine to a direct injected 2005 200 Evinrude Etec. I have no scientific data to report concerning the improved fuel economy of the direct injected engine.
However, every time I return from a fishing excursion, instead of my usual consumption of a 1/2 tank +/-, it is now 1/4 tank +/-.
In simple terms, this equates to very much improved fuel economy. Instead of around a typical fuel burn of 40 gallons, typical fuel burn is now around 20 gallons. I will let others do the rough math.
Direct injection is great stuff!
Doug Vazquez
Salmon Tub posted 09-17-2011 11:31 AM ET (US)
Yes and no regarding fuel economy. For example; my carbed Nissan 90 2-stroke burns approx 9 GPH at WOT and about 1 GPH at idle. Just about any 4-stroke of the same size will get approximately the same or only slightly better WOT results. It is idle where they shine in both fuel economy and quiet operation. My typical day consists of 30 to 45 minutes of mid-throttle run time (3-12 miles) using 1-3 gallons, then, depending on the bite, up to 5 hours of trolling at idle, and subsequently the return home. As you can see, if the fish are in close, I can easily burn twice as much gas during trolling than while running. So for me, the best solution is an EFI 4-stroke since most of the 90-hp models burn only a fraction of the fuel my engine needs at idle.
pcrussell50 posted 09-17-2011 02:00 PM ET (US)
Yay! Another fuel economy thread! (Even though it did not start out as such).
Since the OP is asking about economics, not aesthetics, I will kindly ignore things like smoke and noise, which are well known around here for their immense power to separate a CWW member from the $10,000 (or more) he has lying idly about.
Here's my take on the matter... remember, we are discussing economics, not aesthetics:
IF you are handy with a wrench, there is no contest. Carbureted two-strokes hands down. If you can rebuild a carburetor or punch out and replace seals in lower unit, there is absolutely no contest that a carbureted two stroke will be much, much, MUCH cheaper to own, even long term, than a modern motor. You will never, EVER recoup the $10,000 (or more) difference in price between a modern motor and a carbureted two stroke, on fuel savings alone. (And that's ignoring the fact that a modern motor will need some repairs at some point, and the possibility/likelihood that those repairs will cost a good deal more than they would on a carbureted two-stroke).
IF you are not handy with a wrench, and could not possibly consider re-sealing a lower unit or rebuilding a carburetor, then the picture changes 100%. You are better off having a modern motor, under warranty. An expensive proposition. Look at it this way... skill with a wrench has monetary value. If you do not posses such skills, you still cannot escape that fact, and you will have to substitute money instead.
Marine propulsion will be a more expensive proposition for the person who lacks wrenching skills, or insists on quietness and minimal smoke. Period.
Mattanza, buddy. You said:

quote:
Does this mechanic have a carburetor in his car? Or fuel injection?
If he's a mechanic, he's a fool if he does not have a carburetor in his car. Either that, or he is willing to pay, (MUCH) more for aesthetics, than sensible economics calls for. Here in CA, pre-smog-era, ('75 and older) cars are outrageously expensive. (Smart) people want them, which of course, drives up the cost big-time. So much so, that it is most often cheaper to go with a fuel injected car.
-Peter

TommyWhaler posted 09-17-2011 02:33 PM ET (US)
[Raises new topic. Please contact the moderator to discuss that topic. Contact me via email--jimh]
To answer some questions posed. Yes the mechanic does own a boat, with a 225-HP carburetor engine. I believe he said it was a 60-degree OMC. His statement to me was "when something goes wrong, as it invariably will, you will spend significantly higher amounts of money to have a fuel injected engine repaired, compared to a carburetor motor. $1,000 vs $200. An example he gave was an injector not working properly, and the damage that would result. The motor would run long enough to do serious damage to the piston. Someone interjected older carburetor engines into the equation, where as he was talking 1995 and newer. I am not a mechanic, so I would have to pay for repairs. That bothers me more than the fuel efficiency, even taking into consideration that I took a perfect running 1985 150 Evinrude off the boat. I was scared of the age, and it drank gas at 12-GPH at half-full throttle on a 1973 Outrage 21. He sells DFI, EFI, and carburetor engines, so I don't see how he has an axe to grind.
But I am going to re-power in a month, and I will more than likely buy a used motor. Thus my interest.
MATTANZA posted 09-17-2011 09:28 PM ET (US)
With the price of fuel, and depending on how often you use the boat, fuel economy can play a very big part. hypothetically say you use 25 gallons less fuel per trip, and you use the boat 4 time a month. 100 gal X $3.00 X 12 = $3,600.00. i think i'll keep my dfi.
Tohsgib posted 09-18-2011 10:22 AM ET (US)
You need to get a new mechanic. He is an idiot.
pcrussell50 posted 09-18-2011 12:20 PM ET (US)
Heck yeah he's an idiot. He has a perfect opportunity to steer you into an expensive mistake, (to his benefit), and he blows it.
-Peter
jimh posted 09-18-2011 12:58 PM ET (US)
The concern about the fuel economy difference between outboard engines using carburetors, port fuel injection, and direct fuel injection was raised in the initial article of the discussion. I cannot see how anyone could claim that this discussion's topic did not begin with the topic of fuel economy. It clearly did.
The cost of ownership related to repair costs for a particular engine must include two factors:
--how often repair is required, and
--how expensive the repair will be.
To argue that repair to engines using port-injection or direct-injection fuel methods will require more expensive parts is to over look the frequency of repair. It is widely demonstrated that outboard engines with carburetors often need frequent repair or service to the carburetors due to fuel evaporation, fuel residue, and fuel clogging. The closed design of the fuel system in engines with fuel injectors tends to reduce the occurrence of problems caused by fuel evaporation and fuel residue. This leads to a lower rate of repair.
MATTANZA posted 09-18-2011 01:46 PM ET (US)
[P]ete--[I] have had fuel injection in all of my road vehicles for the past 25 years, and boats for the past 11 years. [N]ever once did [I] have any [problems] with the fuel system or anything else, except a few small non related [problems]. [C]ommon sense, and regular maintenance is all [I] did. [R]un a carburetor vehicle on today[']s fuels and let it sit--you better be a mechanic. [I]'ve been a marine mechanic, and the last thing [I] wanted to do in my spare time was work on my car, truck, or boat. [I]'ve owned carburetor cars, carburetor trucks, and carburetor boats, and did a lot related of repairs. [S]ince [I] got fuel injected, literally nothing but maintenance. [I] don't think your mechanic is an idiot, just antiquated, like some of the opinions on the matter. [I]t's like digital versus analog: they both work, but one[']s more efficient, more reliable, longer lasting, etc.
pcrussell50 posted 09-19-2011 12:05 AM ET (US)
I'll be straight with you. I've never had a carbureted car. But that doesn't change any of my point, which is that all things considered, including purchase price, if you posses basic wrenching skills you are better off economically if you stick with a simple carburetor. Some people here are willing to pay out the you-know-what, for new tech outboard motors in order to have a quiet, smoke-free idle. I pay out the you-know-what to have fast cars with world-class handling. Only I don't labor under the illusion that it makes economic sense to do so. It take it a step further in that I am sickened and disgusted by the unnecessary complexity I must endure in order to have the handling I require in my street cars. My current fun street car is the most amazing machine I have ever owned. Unfortunately, it goes off warranty in 6 months and it is for sale. I cannot risk the expense of keeping it past that point. I have no such requirement for my trucks however, and am constantly on the lookout for pre-smog, carbureted trucks. Only here in California, they are outrageously expensive, and for food reason. If my wife, who thinks more like you, would tolerate a carburetor-era daily driver, we would have one yesterday. But she won't, so again, I take it in the you-know-what to pay for aesthetics.
Where I finally get my respite is in outboards. Three of my boats have carburetor two-cycle engines, and I have three more carburetor two-cycle engines on top of those, with no transoms to hang on. Two of those boats are 50-MPH solid fun, and the third is a VERY nice Whaler. All three combined cost a LOT less than the single E-TEC 115 H.O. I might be forced to buy if "the man"' shuts down my access to Lake Mead.
-Peter
jimh posted 09-19-2011 08:17 AM ET (US)
If you like to tinker with your outboard engine, by all means get one with a carburetor or perhaps six carburetors. You will have plenty to tinker with, if you want.
But, a need to tinker with the carburetors is not endemic in a well-designed two-cycle outboard engine. I owned a nice two-cycle outboard engine with six carburetors. When I first acquired it as a used engine, I had a master mechanic synchronize the throttle plate opening and linkage on all six carburetors. That was the last adjustment to them for the next four years.
ThomasT posted 09-17-2013 09:18 PM ET (US)
[Revived the thread only to completely change the topic.]

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Author	Topic: Repair Cost and Fuel Economy of Outboard Engines Using Carburetors, Port Fuel Injection, and Direct Fuel Injection
TommyWhaler	posted 09-16-2011 05:29 PM ET (US) A reputable outboard mechanic that sells used motors--anything you want--says he wouldn't have [an ouboard engine that used port fuel injection or direct fuel injection]--DFI or EFI--unless [the outboard engine] was new and under warranty. So, if you have [a new outboard engine that uses port fuel injection or direct fuel injection] and [your outboard engine] is under warranty, this thread is not for you. [Huh?--jimh.] [The mechanic's] reasoning is [repair of EFI or DFI engines] is almost five-times more expensive than [repair of a] carburetor motor. In addition, he says that the fuel economy on the c.1995 and newer outboard engines is not that far off the economy of DFI and EFI. What say you?
contender	posted 09-16-2011 06:41 PM ET (US) Do not know about the fuel economy, but to work on the carburetors I do not think they can be any simpler compared to the other type of induction. A mechanic should be able to take a carburetor apart, clean it, and assemble it (with all the parts) properly, no special tools are needed.
MATTANZA	posted 09-17-2011 04:51 AM ET (US) Does this mechanic have a carburetor in his car? Or fuel injection? I was a marine mechanic for over 10 years, and off-and-on for over 20. I'd take DFI or EFI over carburetors any day. My OptiMax is way more dependable than my past motors of experience. In my OUTRAGE 15 with 225-HP OptiMax get 3-MPG at 20-nautical-miles-per-hour. I'd be lucky to get 1.5-MPG with carburetors. Does your mechanic own a boat? If so. what make, yearm and power? That will tell you about the mechanic. Some of the best and smartest mechanics that I've known have never owned boats, so their opinions may not be based on user experience.
jimh	posted 09-17-2011 10:09 AM ET (US) I was going to respond, but I believe that I am disqualified by the criterion set forth in the initial article because I own an outboard engine with direct fuel injection that is under warranty. However, I don't have any plans to sell it and get an outboard with carburetors, if that information is useful to the discussion.
jimh	posted 09-17-2011 10:21 AM ET (US) I don't see much difference in fuel economy between outboard engines using a carburetor and outboard engines using simple port fuel injection schemes, particularly older outboard engines which lack sophisticated engine control systems and run in open loop modes of control. I will give a nod to the simple port fuel injection engines as being easier to start if the operator does not know how to read the owner's manual, easier to start if the temperature is very low, and easier to start if the operator never primes the fuel system. But in the moderate temperatures and sea level elevation that most outboard engines are used, I do not see an overwhelming advantage to port fuel injection over carburetors, and particularly for more modern carburetor engines with smarter control systems and operated by someone who read the owner's manual. Perhaps the best port fuel injection engine made was the Yamaha Ox66 series. Those engines had a closed-loop modern control system. They probably offered improved performance and fuel economy compared to simpler systems on competitors' motors. The fuel economy of direct-injection engine is much improved compared to other methods, particularly in two-cycle engines where direct-injection makes an enormous improvement in fuel economy.
DeeVee	posted 09-17-2011 10:59 AM ET (US) I recently repowered from a 1992 200 Suzuki carburetor engine to a direct injected 2005 200 Evinrude Etec. I have no scientific data to report concerning the improved fuel economy of the direct injected engine. However, every time I return from a fishing excursion, instead of my usual consumption of a 1/2 tank +/-, it is now 1/4 tank +/-. In simple terms, this equates to very much improved fuel economy. Instead of around a typical fuel burn of 40 gallons, typical fuel burn is now around 20 gallons. I will let others do the rough math. Direct injection is great stuff! Doug Vazquez
Salmon Tub	posted 09-17-2011 11:31 AM ET (US) Yes and no regarding fuel economy. For example; my carbed Nissan 90 2-stroke burns approx 9 GPH at WOT and about 1 GPH at idle. Just about any 4-stroke of the same size will get approximately the same or only slightly better WOT results. It is idle where they shine in both fuel economy and quiet operation. My typical day consists of 30 to 45 minutes of mid-throttle run time (3-12 miles) using 1-3 gallons, then, depending on the bite, up to 5 hours of trolling at idle, and subsequently the return home. As you can see, if the fish are in close, I can easily burn twice as much gas during trolling than while running. So for me, the best solution is an EFI 4-stroke since most of the 90-hp models burn only a fraction of the fuel my engine needs at idle.
pcrussell50	posted 09-17-2011 02:00 PM ET (US) Yay! Another fuel economy thread! (Even though it did not start out as such). Since the OP is asking about economics, not aesthetics, I will kindly ignore things like smoke and noise, which are well known around here for their immense power to separate a CWW member from the $10,000 (or more) he has lying idly about. Here's my take on the matter... remember, we are discussing economics, not aesthetics: IF you are handy with a wrench, there is no contest. Carbureted two-strokes hands down. If you can rebuild a carburetor or punch out and replace seals in lower unit, there is absolutely no contest that a carbureted two stroke will be much, much, MUCH cheaper to own, even long term, than a modern motor. You will never, EVER recoup the $10,000 (or more) difference in price between a modern motor and a carbureted two stroke, on fuel savings alone. (And that's ignoring the fact that a modern motor will need some repairs at some point, and the possibility/likelihood that those repairs will cost a good deal more than they would on a carbureted two-stroke). IF you are not handy with a wrench, and could not possibly consider re-sealing a lower unit or rebuilding a carburetor, then the picture changes 100%. You are better off having a modern motor, under warranty. An expensive proposition. Look at it this way... skill with a wrench has monetary value. If you do not posses such skills, you still cannot escape that fact, and you will have to substitute money instead. Marine propulsion will be a more expensive proposition for the person who lacks wrenching skills, or insists on quietness and minimal smoke. Period. Mattanza, buddy. You said: quote: Does this mechanic have a carburetor in his car? Or fuel injection? If he's a mechanic, he's a fool if he does not have a carburetor in his car. Either that, or he is willing to pay, (MUCH) more for aesthetics, than sensible economics calls for. Here in CA, pre-smog-era, ('75 and older) cars are outrageously expensive. (Smart) people want them, which of course, drives up the cost big-time. So much so, that it is most often cheaper to go with a fuel injected car. -Peter
TommyWhaler	posted 09-17-2011 02:33 PM ET (US) [Raises new topic. Please contact the moderator to discuss that topic. Contact me via email--jimh] To answer some questions posed. Yes the mechanic does own a boat, with a 225-HP carburetor engine. I believe he said it was a 60-degree OMC. His statement to me was "when something goes wrong, as it invariably will, you will spend significantly higher amounts of money to have a fuel injected engine repaired, compared to a carburetor motor. $1,000 vs $200. An example he gave was an injector not working properly, and the damage that would result. The motor would run long enough to do serious damage to the piston. Someone interjected older carburetor engines into the equation, where as he was talking 1995 and newer. I am not a mechanic, so I would have to pay for repairs. That bothers me more than the fuel efficiency, even taking into consideration that I took a perfect running 1985 150 Evinrude off the boat. I was scared of the age, and it drank gas at 12-GPH at half-full throttle on a 1973 Outrage 21. He sells DFI, EFI, and carburetor engines, so I don't see how he has an axe to grind. But I am going to re-power in a month, and I will more than likely buy a used motor. Thus my interest.
MATTANZA	posted 09-17-2011 09:28 PM ET (US) With the price of fuel, and depending on how often you use the boat, fuel economy can play a very big part. hypothetically say you use 25 gallons less fuel per trip, and you use the boat 4 time a month. 100 gal X $3.00 X 12 = $3,600.00. i think i'll keep my dfi.
Tohsgib	posted 09-18-2011 10:22 AM ET (US) You need to get a new mechanic. He is an idiot.
pcrussell50	posted 09-18-2011 12:20 PM ET (US) Heck yeah he's an idiot. He has a perfect opportunity to steer you into an expensive mistake, (to his benefit), and he blows it. -Peter
jimh	posted 09-18-2011 12:58 PM ET (US) The concern about the fuel economy difference between outboard engines using carburetors, port fuel injection, and direct fuel injection was raised in the initial article of the discussion. I cannot see how anyone could claim that this discussion's topic did not begin with the topic of fuel economy. It clearly did. The cost of ownership related to repair costs for a particular engine must include two factors: --how often repair is required, and --how expensive the repair will be. To argue that repair to engines using port-injection or direct-injection fuel methods will require more expensive parts is to over look the frequency of repair. It is widely demonstrated that outboard engines with carburetors often need frequent repair or service to the carburetors due to fuel evaporation, fuel residue, and fuel clogging. The closed design of the fuel system in engines with fuel injectors tends to reduce the occurrence of problems caused by fuel evaporation and fuel residue. This leads to a lower rate of repair.
MATTANZA	posted 09-18-2011 01:46 PM ET (US) [P]ete--[I] have had fuel injection in all of my road vehicles for the past 25 years, and boats for the past 11 years. [N]ever once did [I] have any [problems] with the fuel system or anything else, except a few small non related [problems]. [C]ommon sense, and regular maintenance is all [I] did. [R]un a carburetor vehicle on today[']s fuels and let it sit--you better be a mechanic. [I]'ve been a marine mechanic, and the last thing [I] wanted to do in my spare time was work on my car, truck, or boat. [I]'ve owned carburetor cars, carburetor trucks, and carburetor boats, and did a lot related of repairs. [S]ince [I] got fuel injected, literally nothing but maintenance. [I] don't think your mechanic is an idiot, just antiquated, like some of the opinions on the matter. [I]t's like digital versus analog: they both work, but one[']s more efficient, more reliable, longer lasting, etc.
pcrussell50	posted 09-19-2011 12:05 AM ET (US) I'll be straight with you. I've never had a carbureted car. But that doesn't change any of my point, which is that all things considered, including purchase price, if you posses basic wrenching skills you are better off economically if you stick with a simple carburetor. Some people here are willing to pay out the you-know-what, for new tech outboard motors in order to have a quiet, smoke-free idle. I pay out the you-know-what to have fast cars with world-class handling. Only I don't labor under the illusion that it makes economic sense to do so. It take it a step further in that I am sickened and disgusted by the unnecessary complexity I must endure in order to have the handling I require in my street cars. My current fun street car is the most amazing machine I have ever owned. Unfortunately, it goes off warranty in 6 months and it is for sale. I cannot risk the expense of keeping it past that point. I have no such requirement for my trucks however, and am constantly on the lookout for pre-smog, carbureted trucks. Only here in California, they are outrageously expensive, and for food reason. If my wife, who thinks more like you, would tolerate a carburetor-era daily driver, we would have one yesterday. But she won't, so again, I take it in the you-know-what to pay for aesthetics. Where I finally get my respite is in outboards. Three of my boats have carburetor two-cycle engines, and I have three more carburetor two-cycle engines on top of those, with no transoms to hang on. Two of those boats are 50-MPH solid fun, and the third is a VERY nice Whaler. All three combined cost a LOT less than the single E-TEC 115 H.O. I might be forced to buy if "the man"' shuts down my access to Lake Mead. -Peter
jimh	posted 09-19-2011 08:17 AM ET (US) If you like to tinker with your outboard engine, by all means get one with a carburetor or perhaps six carburetors. You will have plenty to tinker with, if you want. But, a need to tinker with the carburetors is not endemic in a well-designed two-cycle outboard engine. I owned a nice two-cycle outboard engine with six carburetors. When I first acquired it as a used engine, I had a master mechanic synchronize the throttle plate opening and linkage on all six carburetors. That was the last adjustment to them for the next four years.
ThomasT	posted 09-17-2013 09:18 PM ET (US) [Revived the thread only to completely change the topic.]