OB vs. I/O - Fuel Economy Question

[mickjetblue]

Re: OB vs. I/O - Fuel Economy Question

I would just throw in a consideration based on the number of carburetors
in ratio to the number of cylinders. That is, if you go with a carburetor motor.
Being fuel usage if your main concern, an engine that has 6 carburetors for
6 cylinders is going to burn much more fuel than an engine that has 1 carburetor
for 4 cylinders. Given they are in the same hp range by about 20hp.

Good luck with what you are looking for at under $5k.

 

[109jb]

Re: OB vs. I/O - Fuel Economy Question

What WAS I thinking? You are so right OJB. Please forgive me and my opinion. Obviously I'm not nearly as intelligent as you regarding boat power. Silly me; I posted based on my past experiences. Please accept my apology. Next time I'll send you my replies first so you can proofread them and enlighten me when I err. Would that be OK with you?

UFM82

UFM82, I've got no problem with anyone stating their opinions, but why would you think you would be able to point out only the faults of one drive type without expecting a rebuttal. Wasn't that exactly what you were doing, rebutting the post previous to yours by Silvertip??

 

[wildmaninal]

Re: OB vs. I/O - Fuel Economy Question

I'll stick to outboards myself. I stripped 2 boats with I/Os and they are a PITA, that's why I took a saw zaw to the 2nd one just recently . Outboards seem to be easier to work on and as said they don't take up any room in the hull.

 

[Silvertip]

Re: OB vs. I/O - Fuel Economy Question

All one needs to do is visit the I/O forum to see how well informed people are about their I/O engines. Wait until spring and you will see how many posts there are about "why does my engine leak water" - or "how did this crack get there?". One can stand along side an outboard and you don't need universal joints in your fingers to work on them. Anyone that has the knowledge to work on an I/O can easily handle a two stroke. And four stroke outboards should be no problem either since -- well -- they are the same as the engine in your I/O.

 

[45Auto]

Re: OB vs. I/O - Fuel Economy Question

All one needs to do is visit the I/O forum to see how well informed people are about their I/O engines.

LMAO!!!!! Great line!! You think Iboats would give me some kind of bonus if I sent in a suggestion that they open some outboard forums for the VERY FEW people who have problems with their outboards??? Oh, sorry, just looked, they DO already have outboard forums with such classic topics as "Why did my motor fall off my boat?"!!

You really think the people on the outboard forums are more informed than the people on the I/O forum? I don't even own an outboard any more but I look over there almost every day just for laughs!!

I personally like 2 strokes. Did the whole motorcycle scene with the Kawasaki and Suzuki triples and the Yamaha RD's. But whether you like it or not, the reality is that under long term conditions a 4 stroke is inherently more reliable than a 2 stroke due to the lubrication system (talking gas engines here, not diesels). The auto market learned that a LONG time ago, the motorcycle and lawnmower market learned it in the late 70's - early 80's, and the boat market is currently in the process of being educated.

If you need lots of power in a small package (chainsaw, RC airplane, etc) it's hard to beat a 2 stroke. But once a few pounds don't make any difference (cars, motorcycles, boats, etc) you're going to find the 4 strokes on top.

 

[arboldt]

Re: OB vs. I/O - Fuel Economy Question

And there you have it, Packman.

Very strong opinions for each side. It's all trade-offs. Arguments so far contast efficiency vs maintenance, performance vs aesthetics, ...

One consideration no one's mentioned yet is that some governments, in their great wisdom, have prohibited 2-stroke engines from certain waters. (search these forums for those threads). If I were in the market for a boat, that might tip the balance toward i/o.

But I think it can be a lot simpler for you. When you start looking, there's going to be only a certain number of boats being sold, and your budget will restrict that number. Look at 'em until you find one you like, whether ob or i/o. As you follow this board, you'll find many comments that few people are really satisfied with their first boat. Live and learn.

As in most things, at a practical budget level, few will ever find the optimum, but most can find a sufficient solution. Tashasdaddy has often posted considerations for buying a boat. I hope you've thought through them.
I guess in my mind the most important is finding one you can afford that can do what you want it to do, then buy it and get on the water. You can always sell it and buy differently in a couple years once you better know what's important to you.

Al

 

[109jb]

Re: OB vs. I/O - Fuel Economy Question

I don't think that either group is more informed, but with an I/O, there is more that you should be informed about. Winterization in particular. If you are not informed there is more potential for the resulting problems to be catastrophic than with an outboard.

As far as pressure lubed vs. mist lubed bearings, you forgot to mention that pressure lubed engines use sleeve bearings and mist lubed use roller bearings. Different lubrication schemes and different bearings. I've had dozens of 2-strokes over the years including my boats, snowmobiles, motorcycles, weedeaters, chainsaws, etc., and have never had a bearing failure in any of them. The bottom line is that both 2 and 4-stroke oiling systems have a track record of proven reliability.

BTW, if you want the ablsolute most reliable oiling system, then premix 2-stroke is hard to beat. If the engine is getting fuel it is also getting oil. No question. If it isn't getting oil then it isn't getting fuel either and is hence not running.

It all comes down to what you want and what is important to you. The pro's and con's of outboard vs. I/O have been beat to death and reliability doesn't really even come into it in my opinion because each has years and years of proven reliability. However, what needs to be done in order to maintain this reliability has been one of the deciding factors for me.

 

[ufm82]

Re: OB vs. I/O - Fuel Economy Question

All I put in my post was a few points I've seen with regards to outboards. I run an outboard on my current boat and love it. I've also had I/Os in the past and have enjoyed them as well. I expressed no loyalty to either drive- I simply stated my thoughts.

I take no offense to any rebuttal of my post. And tone is impossible to express in text so unless ceratin words are used, I have no idea of what tone you are taking when replying. However, certain words and/or phrases imply a tone and your reply employed some of those terms.

"And I guess I/O's are thought controlled since they apparantly don't have steering"

"So I show someone the oil resevoir once on an outboard and they then know where to both check and fill the oil."

"Huh"

Those terms imply disdain to me. I did not attack any one's thoughts- just posted some alternative issues with outboards compared to I/Os. That's all.

Now can we argue something simpler, like Chevy-V-Ford? LOL

UFM82

 

[dingbat]

Re: OB vs. I/O - Fuel Economy Question

BTW, if you want the ablsolute most reliable oiling system, then premix 2-stroke is hard to beat.

No thanks, I?ll stick with the machine specificity built for the task. Humans are far more prone to error than a machine is too failure.

I don?t recall hearing about any machines that forgot to put the plug in or left their keys at home.

 

[109jb]

Re: OB vs. I/O - Fuel Economy Question

All I put in my post was a few points I've seen with regards to outboards. I run an outboard on my current boat and love it. I've also had I/Os in the past and have enjoyed them as well. I expressed no loyalty to either drive- I simply stated my thoughts.

I take no offense to any rebuttal of my post. And tone is impossible to express in text so unless ceratin words are used, I have no idea of what tone you are taking when replying. However, certain words and/or phrases imply a tone and your reply employed some of those terms.

"And I guess I/O's are thought controlled since they apparantly don't have steering"

"So I show someone the oil resevoir once on an outboard and they then know where to both check and fill the oil."

"Huh"

Those terms imply disdain to me. I did not attack any one's thoughts- just posted some alternative issues with outboards compared to I/Os. That's all.

Now can we argue something simpler, like Chevy-V-Ford? LOL

UFM82

You are right. My comments did show disdain for the comments you made, but intent was not a personal attack, but rather to simply highlight my opposition to the specific comments. However, if you look back at your original post it also had an air of disdain in your reply to Silvertip's comments. Again, my intent was only to rebutt the specific comments and if you were offended I am sorry, but the points I was trying to make remain.

 

[109jb]

Re: OB vs. I/O - Fuel Economy Question

No thanks, I?ll stick with the machine specificity built for the task. Humans are far more prone to error than a machine is too failure.

I don?t recall hearing about any machines that forgot to put the plug in or left their keys at home.

I too prefer mechanical means (ie: oil injection), but not because I think I would forget, but because the oil injection ratio is tailored to what the engine requires. More oil at higher power settings, less oil at lower power settings. At least for me, forgetting to add oil to the fuel in my Starcraft (premix engine), seems very unlikely since it goes in before the fuel the way I do it. Whether the possibility of forgetting to add oil to the fuel is a strike against these engines is debatable since it is also possible to forget to check the oil level on an injected 2-stroke or a 4-stroke. In the case of I/O's it is possible to forget to do other things like periodically changing belts, hoses, bellows, winterize, etc.

 

[ufm82]

Re: OB vs. I/O - Fuel Economy Question

We're good ojb. Fuh-get about it...

I also love the oil-injection as opposed to premixing specifically for the reasons you listed. My biggest issue with it is a lack of notification other than a warning buzzer which may not be heard at WOT with the wind roaring in your ears. You find out that the oil isn't getting to the engine when the engine goes BOOM. With the advent of smartgauges and the like maybe that's not a factor anymore but keep in mind the original poster's budget.

UFM82

Not that an I/O has an oil light normally.

 

[45Auto]

Re: OB vs. I/O - Fuel Economy Question

you forgot to mention that pressure lubed engines use sleeve bearings and mist lubed use roller bearings

Didn't forget to mention it, figured anybody interested enough to follow the discussion this far would know the difference (by the way, they're not "sleeve bearings", they're "shell bearings" - totally different things).

The pressurized shell bearings carry the load on a pressurized film of oil. Theoretically no metal to metal contact, except on start up with no oil pressure. Not uncommon for them to run for hundreds of thousands of miles.

The roller bearings used in a typical 2-stroke gas engine (NOT a commercial 2-stroke diesel, totally different animal there, uses a typical automotive pressurized oil system) have a much shorter life expectancy due to the way they carry the load with metal on metal contact.

I've had dozens of 2-strokes over the years including my boats, snowmobiles, motorcycles, weedeaters, chainsaws, etc., and have never had a bearing failure in any of them.

Yep, you've had a bunch of 2-stroke toys over the years that you've never used for more than a couple of hours at a time. Add up ALL your hours on all of them and it's probably significantly less than the time you put on a car in a couple of years (figure 12000 miles at 60 MPH, would be 200 hours a year, since you don't average 60 MPH it would really be many more hours on the car).

BTW, if you want the ablsolute most reliable oiling system, then premix 2-stroke is hard to beat.

You must be dreaming. Can't count the number of trashed 2-strokes with the piston melted to the cylinder that I've seen where someone forgot to mix the oil or used the wrong gas can.

If you really want a reliable oil system, you don't want one where your engine is consuming the lubricating oil. Too many ways for someone to forget to keep track of adding the oil.

 

[abj87]

Re: OB vs. I/O - Fuel Economy Question

not to mention that two strokes are dirtier than all get out. The one think i don't miss about the 2 stroke is the blue cloud that follows you around.

True o/b's require less maintenance, but as long as your not totally numb you can probably handle the extra work.;

 

[109jb]

Re: OB vs. I/O - Fuel Economy Question

Didn't forget to mention it, figured anybody interested enough to follow the discussion this far would know the difference (by the way, they're not "sleeve bearings", they're "shell bearings" - totally different things).

The pressurized shell bearings carry the load on a pressurized film of oil. Theoretically no metal to metal contact, except on start up with no oil pressure. Not uncommon for them to run for hundreds of thousands of miles.

The roller bearings used in a typical 2-stroke gas engine (NOT a commercial 2-stroke diesel, totally different animal there, uses a typical automotive pressurized oil system) have a much shorter life expectancy due to the way they carry the load with metal on metal contact.

Yep, you've had a bunch of 2-stroke toys over the years that you've never used for more than a couple of hours at a time. Add up ALL your hours on all of them and it's probably significantly less than the time you put on a car in a couple of years (figure 12000 miles at 60 MPH, would be 200 hours a year, since you don't average 60 MPH it would really be many more hours on the car).

You must be dreaming. Can't count the number of trashed 2-strokes with the piston melted to the cylinder that I've seen where someone forgot to mix the oil or used the wrong gas can.

If you really want a reliable oil system, you don't want one where your engine is consuming the lubricating oil. Too many ways for someone to forget to keep track of adding the oil.

First of all, an engine bearing IS a sleeve bearing. It is simply a pressure lubricated split-sleeve bearing. Sleeve bearings can be split, self lubricated, pressure lubricated, etc. When the 2 shells of an engine bearing are installed they form a pressure lubricated plain sleeve bearing. I guess you are nit picking to attempt to discredit. That doesn't matter though as you knew exactly what I was talking about.

As far as my toys, I have 2 snowmobiles that both have in excess of 15000 miles. I also had a Kawasaki S3 motorcycle that had abot 15000 when I sold it. That doesn't matter either though. The bottom line is that you state that the mist lubricated roller bearings system in 2-stroke outboards is an inferior system to the pressure lubricated bearing in a car type 4-stroke. Maybe so, but it works and has proven itself for many many years as a reliable system. Reliable enough that if the engine is maintained per manufacturer's instructions, chances are that the bearings won't be the first thing to fail if they ever do fail during the engine's life.

On the premix subject, you mention forgetting the oil in the fuel. Granted that can happen, but if it isn't forgotten then there is no way that the engine doesn't get oil if it is running. That was my point. Oil injected or pressure lubricated systems can have oil system failures that allow the engine to continue to run to destruction. These failures aren't common on either of these, but can and do occasionally happen. Oil injection pumps fail, resevoir lines can get plugged, oil pumps can wear or fail, pressure relief valves can stick, oil pickups can come loose from the pump, etc. My point was that if the premix fuel has the proper mix of oil, the engine WILL be getting the oil it needs if it is running.

As I have said before, both I/O's and outboards can be maintained such that they have good reliability. The choice depends on what you are specifically looking for in the boat in general and the amount of maintenance you want to do. Both require maintenance, but there is more of it on an I/O.

 

[curling_coach]

Re: OB vs. I/O - Fuel Economy Question

Well, having only joined iboats about a month ago and reading this thread I just want to thank everyone for making my life real miserable now. LOL. It is all good though. This thread has opened up another set of questions regarding what motor type to get even though I had made a decision on what boat I wanted to purchase. Allow me to regress a bit.
Like a lot of other new members I am new to this boating scene. I have had the pleasure to drive a couple of boats, mainly aluminum, but would like to finally own one after about 10 years of talking about it, being reliant on friends & family and being a little whipped :redface:.
After deciding what reasons I wanted a boat for and spending the last couple months looking at as many different manufacturers I could find, alum & fiberglass, boat lengths, motor sizes, motor types (I/B mainly), bodies of water I would use it on the whole kit'n'caboodle I made a decision and almost purchased what I thought was MY boat, a Glastron 185SF w/ 4.3 VP I/B. Then the economy goes into the crapper and if I want to buy from the US it is going to cost me another 30% plus our dreaded GST tax. Up until a month or so ago I could have received what I thought was a better deal buying south of the border.
Then I come across this post and WOW some new lights go on. Well now I have a bit more time to investigate the new information I discovered tonight.
Thank you to everyone and their respective opinions concerning the I/B or O/B. Some of the information shared especially the parts of maintenance was an eye opener and is making me revisit the O/B.
I am not a mechanic, don't really relish taking an I/B in every year for expensive winterizations/summerizations etc. so having the ease of the O/B maintenance explained in good detail opened up my eyes. Not that I expect things to be easy but being able to use an O/B a bit longer without fear of weather freezing unexpectedly and possibly screwing up an I/B, seems like a good idea when all I have to do is unscrew a couple of plugs compared to 4 or 5 in the I/B along with all the other necessary maintenance.
I don't have to worry about what the "girls" think, I am long past that so I think I will re-look at the aluminum with an O/B. I can probably still get a motor that will be sufficent for the water sports but this will really be used for fishing.

A question I do have have though isn't the new technology 4 stroke and fuel injected? Wasn't the 2 stroke where you had to mix the fuel & oil?

A friend has a 17 or 18 ft crestliner with a 60 HP merc on it and it seems OK for the fishing but if I wanted to tow skiers or tubers would I not need something along the lines of 115HP or more in an O/B?

Fantastic site this iboats forum. It looks like everyone has a wealth of knowledge they are willing to share and that makes for an exceptional community of people. Glad I have joined and look forward to further explorations as I go through each page and each topic.

 

[QC]

Re: OB vs. I/O - Fuel Economy Question

A question I do have have though isn't the new technology 4 stroke and fuel injected? Wasn't the 2 stroke where you had to mix the fuel & oil?

Actually there are some very good electronically fuel injected two cycles on the market that are equal on fuel and emissions to their heavier four-stroke cousins . . . The Merc Optimax and Evinrude E-Tec are two good examples. Also many two cycles have had a separate oil tank and injection system that takes the mixing out of the equation for many many years.

Welcome aboard . . .

 

[briguy2817]

Re: OB vs. I/O - Fuel Economy Question

I look forward to the smell of two cycle oil burning at first start up this spring. Of course, by fall I may change my mind,onnly to have to wait until next spring to start the cycle all over again.

Brian

 

[haskindm]

Re: OB vs. I/O - Fuel Economy Question

Wow! I bet the OP got more than he ever bargained for. I am a huge fan of outboards and would probably never buy a boat with anything else. That would be true even if OB technology was still where it was in the '80's. With the new technology, I am really in love with outboards. That said, it is a personal choice. I/O will GENERALLY be less expensive initially. In the type of boat that the OP is looking for, there are probably many more boats available with I/O's than with OB's. Just be aware of the maintenance that is required whichever power plant you opt for and have the boat/motor checked over by someone very knowledgeable prior to the purchase.

One other thing. If you are really concerned with fuel economy DON'T BUY A BOAT! They all use lots of fuel, especially if you want to go fast! The difference in the money spent for an outboard vs. an I/O during the course of a season will be a VERY small percentage of the cost of owning a boat. If it is even a 25% advantage for an I/O and you burn 200 gallons of gas per year and gas is $3.50 per gallon, you would burn 200 gallons with the outboard and only 150 gallons with the I/O for a savings of $175. Don't make a boat purchase based on saving $175 per year. There have been arguments presented giving advantages/disadvantages for both systems that far outweigh that tiny savings.

 

[govols019]

Re: OB vs. I/O - Fuel Economy Question

I love the smell of two stroke oil in the morning.