I/O vs OB

[Lou C]

In fresh water regions there is no reason not to have an I/O. In salt water regions there are some basic reasons why the OB will be less trouble over time. When people say I/Os are cheaper to repower, in salt water regions it would be wise to keep these things in mind. Yes, the SBC is cheaper than an OB power head. BUT, to that you will want to add:
Closed cooling, or face the problems cast iron corrosion causes in salt water over time, ie as the engine ages, a gradual tendency to overheating due to the way cast iron corrodes. So here you are spending about $900 extra, plus installation if you can't do it yourself. If you don't buy this pull off your thermostat housing and look at it. Flaking cast iron. Look in the intake manifold. Same thing. Eventually the cooling passages get so clogged with either rust flakes or sand that its hard to keep temps under control. At least with a heat exchanger it can be cleaned out or eventually replaced if needed, saving the engine from that damage.
Replace the exhaust system every 5-7 years, (800-900 bucks parts price alone per engine) or face the risk of water in a cyl and a ruined engine.
Keep in mind in salt water the transom mounts of I/Os, esp Mercruisers, suffer due to leaks and salt water corrosion. This causes leaks around the steering arm and loosness in the hinge pins. Eventually these need major work, or replacement. For some reason this is not common on OMC Cobras or Volvo SXs. Not an issue on an outboard.

Lastly there is the safety difference. It is safer to not have the engine electrical components in the bilge. It is safer to not have to depend on a rubber bellows to keep water out of the boat. While both of these issues can be mitigated via good maintenance practices, it is what it is.
One thing I know from experience, you never see a work boat of any kind used in the water all the time with I/Os here.

When people say, well the SBC is much cheaper to replace than the OB power head, well yes that is true but its only half the story of the repairs that will come due in the salt pond....

To me this is like the choice of trailers, no one would EVER choose a painted steel trailer for a salt water boat, unless you have it launched by a marina with slings. So if you want to run an I/O in salt keep these things in mind, 5-7 years replace complete exhaust system, 15 years, engine may need complete replacement due to salt corrosion, and you best be pulling the drive every year to keep on top of that too.

 

[Pat_220v]

I'm sure this has been bought up before......maybe even by myself.
Interested to now what others think..............I'll keep my opinion to myself for now.............

I think it depends on the person. For me I/O offers several advantages. However, understand I use my boat on the great lakes, and I use a system to remove the boat from the water after every use.

I purchased a boat expecting considerable costs after down payment. I expected to be able to do some maintenance tasks myself.

For me, in my price and size range, boats with 4 cycle engines used far less gas then 2 cycles.
For me, the boats of size I desired with 4 cycle engines were I/Os or inboards
Inboards seem as rare as hens teeth and the ones I saw scared me.
I detest the smell of exhaust smoke. I hate the smell of two cycle exhaust smoke.
I dislike the sound of a two cycle motor.
The quieter a motor, the better.
I like to idle my boat for long periods of time. Frequently in gear. It seemed to me outboards I was looking at had issues with this.
I plan to tap the engine for heat, with a heater core like in your car. Alternative solutions appear to be scary to me.
In days past I have done some work on cars, I may not be a mechanic but it is something I somewhat familiar with.
I feel I/O has superior sea handling
I feel I/O has a great deal less risk of water coming over the transom

I feel that with maintenance I can afford (done by a mechanic everyone in the area seems to recommend) all boats have the same reliability regardless of age, size, type, or configuration. I felt the maintenance costs on any of the newer outboards ( DFI ) was out of my reach.

 

[Pusher]

My dad's i/o's are always needing work. If I have to work on an engine I'd rather work on it standing up. Plus he's too out of shape to do a lot if his own work so his boys get to climb in there.

I like the idea of an I/O conversion to OB with pod and swim platform for cooler and access door to platform.

I also like that you can swap everything over to a new hull (trailer included) and keep on cruising.

If I didn't boat for fishing then it might be different.

 

[WIMUSKY]

I detest the smell of exhaust smoke. I hate the smell of two cycle exhaust smoke.
I dislike the sound of a two cycle motor.
The quieter a motor, the better.
I like to idle my boat for long periods of time. Frequently in gear. It seemed to me outboards I was looking at had issues with this.

Those points are where a 4 stroke or E-Tec O/B shine too.........

 

[Pat_220v]

Those points are where a 4 stroke or E-Tec O/B shine too.........

I have heard good things about E-Tec 2 cycle outboards. The direct injection DFI system seems to be the magic bullet for them. They also seemed to have very good gas mileage, better then I/O.

I also heard though they were expensive to keep maintained. I am not sure if this is true though. For some reason I received the impression both the parts are expensive and the labor is expensive. Apparently unlike cars the parts and testing equipment is not widely available/standardized?


What I would love to know is if EFIs on I/Os followed automotive standards and testing equipment. It is not something I would change now, but I am curious.

 

[WIMUSKY]

I don't know if E-Tecs are expensive to maintain of not. I believe you don't have to touch them for the first 300hrs.....

 

[bruceb58]

What I would love to know is if EFIs on I/Os followed automotive standards and testing equipment. It is not something I would change now, but I am curious.

They don't use OBD-II if that is your question. I bought a Rinda for my outboard in my sig.

I love my 4 stroke EFI Mercury outboard.

 

[Pat_220v]

Lastly there is the safety difference. It is safer to not have the engine electrical components in the bilge. It is safer to not have to depend on a rubber bellows to keep water out of the boat. While both of these issues can be mitigated via good maintenance practices, it is what it is.
One thing I know from experience, you never see a work boat of any kind used in the water all the time with I/Os here.

I live in a very different area then you. Where I am at, most work boats use straight inboards. I have never seen an outboard on a work boat.
our fishing boats look like this: http://pics.boatnerd.com/v/ship1/album57/album2677/

The small work tugs are all straight inboards.

The park service does have a few I/Os, something like this: http://pics.boatnerd.com/v/ship1/alb...T0111.jpg.html

The small police and coast guard boats do use outboards, but I think they are more for show then anything. The coast guard quick response boat uses jet drives: picture, and they always respond with this one if they are going to respond.


The Charter fishing guys are over 50% single engine I/Os. From what I have seen most of these do not have a backup outboard. The ones with a backup outboard do not seem to use them for trolling from what I have seen. There are others, usually twin engine and/or straight shaft. I do not know of any outboard charters off the top of my head, but I imagine they exist in the area. This might be driven by the type of boat used, typically some sort of enclosed bow / cuddy cabin with a hard top around 25'.