Inboard/Outboards Vs Outboards
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rockdog
Well-Known Member
The comparison generally is a 1987 i/o vs a different boat with a 2017 Yamaha hanging off the back. The answer is obvious.
But if you compare 2 2017 models let’s say of equal hp and years.....then there are pro’s and cons to both and it’s a fair comparison. But it’s not a landslide one way when you factor in money.
But if you compare 2 2017 models let’s say of equal hp and years.....then there are pro’s and cons to both and it’s a fair comparison. But it’s not a landslide one way when you factor in money.
wolf
Well-Known Member
I have had both and prefer the inboard for one reason cost a 300 hp yammy is about 32 grand a 350 chev rebuild is easy maybe 3 grand? only good thing about a outboard is they last until you hear POP and BANG then you throw it away another 32 grand i know of one guy who has gone thru 3 motors in 7 years ... yammys...... they all have faults .Comes down to the old debate Ford versus chevy and dodge etc
I am currently running the brand new 300 hp volvo 2018 with the dps leg and love it but yes working on it no way just like the new ones all computer and such and if you dont have the program your f#%&$ look at some of the old old boats with a 305 or 350 in them still going there isnt to many old outboards still going that are over 30 years old. it all depends on what your comfortable with the old days of working on engines are basically over not like the old 350 chevy you could fix that thing with a pair of vise grips and a cresent wrench LOL LOL....things were simpler 30 years ago.... not now.
If i was guiding off shore with a big boat and money no object id have a turbo diesel engine, as that is a working man engine , but for the 100 hours i put on a main every year and at 10 GPH i want a inboard. not something that sucks between 14 to 17 GPH
I am currently running the brand new 300 hp volvo 2018 with the dps leg and love it but yes working on it no way just like the new ones all computer and such and if you dont have the program your f#%&$ look at some of the old old boats with a 305 or 350 in them still going there isnt to many old outboards still going that are over 30 years old. it all depends on what your comfortable with the old days of working on engines are basically over not like the old 350 chevy you could fix that thing with a pair of vise grips and a cresent wrench LOL LOL....things were simpler 30 years ago.... not now.
If i was guiding off shore with a big boat and money no object id have a turbo diesel engine, as that is a working man engine , but for the 100 hours i put on a main every year and at 10 GPH i want a inboard. not something that sucks between 14 to 17 GPH
In general I/O's & inboards whether they be gas or diesel used on the type of boats most of us have are marinized car/truck engines. Most of them sit in the bilge in the aft. In rough seas, water in the bilge will slosh around, get into the front pulley's flinging corrosive S/W all around the engine. They are designed to push a highway vehicle at cruising speeds requiring at most 20% of output power most of the time with very brief periods requiring 80% or more of power. I have heard that the load on a marinized road engine at cruising speed in a boat is like driving a road vehicle up at steep hill at 80 MPH. The 350 in my SeaRay would not tolerate much over 4200 RPM.
My neighbor used to gill net using an I/O 454 in Alaska. He said to avoid corrosion, they pulled the engine & stored in indoors during the winter. My experience mooring the 350 Sea Ray in Tofino was that when I came up to use it some $20 car engine part would be corroded - temp gauge wiring, etc.
If you can mitigate all the above then the I/O/inboard would be OK.
For me it's a reliability versus cost issue.
FYI for fishing, nothing beats straight shafts; no running gear off the back of the boat to avoid.
My neighbor used to gill net using an I/O 454 in Alaska. He said to avoid corrosion, they pulled the engine & stored in indoors during the winter. My experience mooring the 350 Sea Ray in Tofino was that when I came up to use it some $20 car engine part would be corroded - temp gauge wiring, etc.
If you can mitigate all the above then the I/O/inboard would be OK.
I'd say comparing both engines new the O/B costs about twice the 350. I'd say that if I don't mind the fuel costs, the yammy gives me twice the usable HP at twice the money.
For me it's a reliability versus cost issue.
FYI for fishing, nothing beats straight shafts; no running gear off the back of the boat to avoid.
rockdog
Well-Known Member
Leaving or having salt water in the bilge is what I believe to be the main killer over time. Its the corrosion on older motors that cause most of the problems. I don't know why people would leave water in the bilge to be 'sloshing' around. Turn on the bilge pump? That's just basic stuff, but its also what I mean by simply looking after it.
I don't necessarily agree with your second comment about engine load. The engines used in boats are not quite the same. Its not as simple as pull from a car and drop in a boat. Either way, these 'car' engines are also used in towing applications as well as many different industrial applications and they get run hard in some cases.
There is also a load on outboard motors. They both handle loads just fine.
Aquaholic
Crew Member
Cruise in a car at 3500 rpm, back off the gas and you roll for a quarter mile. Cruise in a boat at 3500 rpm, back off the throttle and the boats stops in seconds. Marine engines usually have a different cam and years ago the carbs were jetted differently. Automotive carb runs too lean in the mid rpm range where a boat usually cruises at as the mid range load is significant. Marinized automotive engines weren’t just the funny manifolds.
wildmanyeah
Crew Member
would you recommend a I/O to a new boat owner?
Aquaholic
Crew Member
agreed, no argument at all. Just adding some more first hand experience. Thanks.
rockdog
Well-Known Member
Not an old one but newer? Why not?
Would you recommend a boat with a 1993 2 stroke 175 merc with 1709 hours on it to a new boat owner?
I have a friend who isn’t mechanically inclined. He Bought a boat 10 years ago. The motor it came with (175 merc 2 stroke) cooked. So he replaced it with a used 200 2 stroke merc. These are the older ones. Cost him another few g’s after it was mounted. 1 year warranty. 3 years later pooched again. So he now has put a new Merc on the back and with rigging and all that, there’s 22g. In 10 years, this boat has cost him close to 45g, maybe more because every hiccup and the boat goes to a shop. During the same period, I had a 3.0 I/o and it ran flawlessly. Mine was also a ‘93 vintage. My boat cost me virtually nothing in that same time period.
so what’s the answer? I don’t think there is a right answer wmy .I suppose it would depend on how much money someone was prepared to spend. I can’t have 22,000 invested in just a motor, so my I/o gets me out there and catching fish like everyone else at a fraction of the cost.
Rain City
Crew Member
I had a 4.3L mpi in my new 2007 3500 lb Maxum 185 and that thing went like all hell and cost pennies to run. Just did regular maintenance on it for the 7 years I owned it. Sold to a guy on the coast and he's now had it for another 6 years with zero issues. Lots of power for the load is what's key I think. Now my 2006 6500 lb Bayliner with a carburated 5.0L had all kinds of issues. Blown valves and dead sensors the list goes on. The guy that owned it prior to me didn't take care of it at all though and you could tell. So yes I would 100% recomend a nice new, well maintained I/O because swim grids are a blast to well, swim off of.
wildmanyeah
Crew Member
just an open ended question no right or wrong answer required.
rockdog
Well-Known Member
I suppose that question would require a lot of other info. Such as usage (purpose ski, fish, both?), salt or fresh or both, Size of boat, budget, mooring?..but as Rain City also just said, I would have no issue recommending an inboard/outboard boat to my best friend if he really liked the boat and it was newer. I think age is very important.
ab1752
Crew Member
For any boat, and particularly one with an IO, one look into the bilge tells me pretty much all I need to know about how that boat has been maintained. If I see water sloshing around in there, full of grease and it clearly has been for a long while, to me that's a sure sign its been neglected. Corrosion in particular especially since most of these engines are Chevy blocks with the starter buried way down below in the back.
On our boat, I keep a Ryobi portable wet / dry vac on board and I use it to remove any water that might appear in the bilge. I realize this is likely overkill but once the bilge is clean it is quick maintenance and then one look down there tells me if something is amiss. I personally think that clean stuff breaks way less than dirty so I like to make sure things are kept tidy.
On our boat, I keep a Ryobi portable wet / dry vac on board and I use it to remove any water that might appear in the bilge. I realize this is likely overkill but once the bilge is clean it is quick maintenance and then one look down there tells me if something is amiss. I personally think that clean stuff breaks way less than dirty so I like to make sure things are kept tidy.
Gear'n'beer!
Well-Known Member
Mechanical stuff breaks......it's not rocket appliances here folks. They both have pros and cons......I personally have an outboard, but from my perspective I certainly wouldn't steer away from in IO.
wolf
Well-Known Member
Marine inboard is totally different from a truck engine, back 40 years ago NO and about 15 years ago the marine world went wit Roller cam and roller rockers so it didnt effect the engine my boat when I got it I rebuilt it to a 383 stroker with all the stuff new everything and it was amazing engine and still is 425 hp and my boat went 49 mph total cost of rebuild was 2800 bucks... for the complete engine with machining...
Now fast forward to the beast thats in it now 300 hp engine now though has direct fuel inject and variable time cam and WOT is only 43 mph . i cruise at 26 to 30 and burns at 10.4 GPH and my boat is VERY heavy about 8500 to 9000 lbs loaded. ALL machinery is the same if you dont look after it and ride it hard and put away wet you will have problems...
as for HP to usable HP all comes down to gearing and prop selections ( and then your into a whole different word) current gear ration I have is 2.32 to 1
the old 290 i had was 1.93 to 1 big difference. And ill be honest have no clue what a outboard drive ratio is.
What I tell all new guys buying a used boat with inboard is quite simple I tell them throw away the manifolds and risers and start new ( i would replace no matter what every 4 years ) put a new marine starter in at same time and get the old one rebuilt replace the wiring and plugs and cap and rotor start fresh and you will be good for many hours on the water
Now fast forward to the beast thats in it now 300 hp engine now though has direct fuel inject and variable time cam and WOT is only 43 mph . i cruise at 26 to 30 and burns at 10.4 GPH and my boat is VERY heavy about 8500 to 9000 lbs loaded. ALL machinery is the same if you dont look after it and ride it hard and put away wet you will have problems...
as for HP to usable HP all comes down to gearing and prop selections ( and then your into a whole different word) current gear ration I have is 2.32 to 1
the old 290 i had was 1.93 to 1 big difference. And ill be honest have no clue what a outboard drive ratio is.
What I tell all new guys buying a used boat with inboard is quite simple I tell them throw away the manifolds and risers and start new ( i would replace no matter what every 4 years ) put a new marine starter in at same time and get the old one rebuilt replace the wiring and plugs and cap and rotor start fresh and you will be good for many hours on the water
Foxsea
Well-Known Member
There are some excellent observations on this thread. I've had both stern drives and outboards and have had little trouble with either one. As several have noted, a lot of that is as a result of care and maintenance. Another factor of note is that many boats are sold underpowered. That puts more strain on the entire drive train resulting in poor performance, poor economy, more needed maintenance and reduced longevity, no matter what the drive type. Then there is age.
The technology used in modern outboards and stern drives is far and away better than what we had even 15 years ago. ECM's, electronic ignition and electronic fuel injection are great improvements. Reliability has never been better. This while also providing much better emission controls on both. Newer is better.
Many years ago, sterndrives provided better performance and economy than outboards. Both have improved dramatically. But now there are some compelling advantages to many of today's 4 stroke outboards.
The technology used in modern outboards and stern drives is far and away better than what we had even 15 years ago. ECM's, electronic ignition and electronic fuel injection are great improvements. Reliability has never been better. This while also providing much better emission controls on both. Newer is better.
Many years ago, sterndrives provided better performance and economy than outboards. Both have improved dramatically. But now there are some compelling advantages to many of today's 4 stroke outboards.
- Outboards are designed and built specifically for boating. Common inboard/outboards are still “marinized” automobile engines repurposed for boats.
- Especially important in smaller boats, outboards provide more room inside the boat because they are installed on the transom, outside the boat. I/O engines are in the cockpit which takes up an area of the boat that can be better used for user convenience and comfort.
- With equivalent outputs, the modern four stroke outboards offer higher performance–quicker to plane, quicker 0 to 30 MPH, and faster top-end.
- Four-stroke outboards can offer better fuel economy: less GPH, more MPG than I/O motors.
- Outboards offer better power to weight ratio. Typically a four-stroke outboard is approximately 400 to 500 pounds lighter than its sterndrive counterpart.
- Because of driveline losses, sterndrives deliver less power to the propeller than outboards.
- Outboards have advanced, internal corrosion protection, plus the leg can be tilted clear of the water, reducing potential corrosion and marine growth.
- Outboards have a shallow draft allowing you to operate in less water than you can with an I/O.
- Outboard motors are much more accessible and require less maintenance (no cooling system, manifolds, risers, bellows and universal joints to look after.) Easier to work on with the outboard being outside the boat.
- No special winterizing needed on outboards.
- No possibility of catastrophic hull breach as a result of collision or failed component with an outboard.
- In the last 4 years, registrations of boats with outboards have increased +29.8% while those with I/O’s have declined 18.2%. In other words, manufacturers determined more people want four-stroke outboards.
- When it's time, a boat equipped with an outboard is easier to repower. Many older sterndrive boats are given new life with pods and outboards.
rockdog
Well-Known Member
Good post Foxsea.
This bullet point is interesting.
"Especially important in smaller boats, outboards provide more room inside the boat because they are installed on the transom, outside the boat. I/O engines are in the cockpit which takes up an area of the boat that can be better used for user convenience and comfort."
This is one thing about podded boats that I never liked. I don't like having a big outboard and kicker hanging 4 feet off the back of the boat. It is space in the water that I cannot use for playing a fish, netting or just swimming. It also becomes a bit of a drag trying to pull skiers and tubers with that back there. I use my boat as multi purpose, so that is also a factor.
Winterizing - this to me is a bit of a misconception, Its not hard. Air doesn't freeze. So much like a travel trailer, if you get the water out then there is no problem. I added a valve to drain the heat exchanger, as well as the exhaust manifold. When I need to winterize I open both valves and all the water drains out and I'm done, winterized. I've done it that way for 11 years, zero issues. With my travel trailer its the same thing, drain all the water and blow out the lines, no issues.
This bullet point is interesting.
"Especially important in smaller boats, outboards provide more room inside the boat because they are installed on the transom, outside the boat. I/O engines are in the cockpit which takes up an area of the boat that can be better used for user convenience and comfort."
This is one thing about podded boats that I never liked. I don't like having a big outboard and kicker hanging 4 feet off the back of the boat. It is space in the water that I cannot use for playing a fish, netting or just swimming. It also becomes a bit of a drag trying to pull skiers and tubers with that back there. I use my boat as multi purpose, so that is also a factor.
Winterizing - this to me is a bit of a misconception, Its not hard. Air doesn't freeze. So much like a travel trailer, if you get the water out then there is no problem. I added a valve to drain the heat exchanger, as well as the exhaust manifold. When I need to winterize I open both valves and all the water drains out and I'm done, winterized. I've done it that way for 11 years, zero issues. With my travel trailer its the same thing, drain all the water and blow out the lines, no issues.
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Rain City
Crew Member
I love my current diesels for the power and ridiculously low running costs. I think in bigger heavier boats the argument starts to sway back toward diesel I/O for that reason. 15000lb dry and probably pushing 18000lb filled to the tits and I don't EVER think about fuel costs going up or not getting up on step. I can't imagine what the twin 350s would cost to run.
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