Inboard vs. IO

[NoGin]

I have had really poor luck with my IO this summer. I have the original 3.7 4 cyl Merc and Alpha 1 stern drives in my boat and have continued problems that have led me to seriously consider selling the boat. i love the boat, it's just the IOs that are causing me such grief.

I have a friend with a Rinker 2003 with the 350 merc and Bravo 3 drive. This any better? People tell me they would never go back to IOs after having problems with them and switching to inboards.

 

[45Auto]

Re: Inboard vs. IO

Maintenance on a B3 I/O is no different than the twin Alpha's you currently have. You have the same bellows, u-joints, 90 degree shafts, etc, just half as many. But the parts will cost you about twice as much .......

A pure inboard is much preferable to an I/O on a boat left in the water. Only major holes in the hull are rudder and shaft packings. No rubber bellows to leak. They're fairly rare on boats less than about 30' because of length and weight issues.

From what I've seen on I/O's on bigger boats left in the water maintenance is their downfall. They need to be pulled every year, oil changed, anodes checked, u-joints lubed, bellows checked, alignment checked, etc. But when most people have to pay marina prices to have a boat hauled and serviced, especially as the boat gets older, they tend to let the maintenance slide as long as everything SEEMS okay. That's when the leaking bellows, leaking seal, misaligned drive, etc, start to rack up some high costs when it's time to pay for playing.

 

[rodbolt]

Re: Inboard vs. IO

given a choice between my 21 shamrock and the 27 albemarle I sold take the inboard anyday.
I sold the shamrock cause the waters here are so shallow and I made a profit. I sold the albemarle for shallow water,twin jack shafted volvos and I made a large profit.
only draw back to the inboard is they typically dont take whacking the bottom well at all.

 

[TilliamWe]

Re: Inboard vs. IO

NoGin, don't judge all I/O (or all Mercruisers) by the poorly designed and horribly implemented 3.7s (470) in your boat. They were a bad idea when they were new, let alone 20-30 years later.

Bravo 3s are a superior drive to the Alpha, and a 350MAG MPI is FAR FAR FAR superior to a 3.7. They still need ALL the routine maintenance of any I/O, though. Just as 45Auto points out. In addition, Bravo 3s, with their two big stainless steel props, and one less sacrificial anode, are predisposed to corrosion issues. They have to be watched closely, have the Proper anodes for the type of water they are in, and they must be pulled every year and thoroughly inspected, especially the rear bearing carrier behind the props.

Straight inboards are a better choice for a boat that is slipped in the water all the time. Especially salt or brackish water. But I don't like the limitations they bring, such as inability to beach them, run in shallow water, and no ability to trim the running gear up at cruising speed to raise more bow out of the water and go faster or more efficiently cruise. But hey, that's me.

 

[NoGin]

Re: Inboard vs. IO

So far the winner is still IO. I completed an initial inspection and am leaning towards a 2003 Rinker 270 Fiesta Vee with single Merc 350 and Bravo 3 with two counter rotating props. Anyone familiar with this drive/prop set up?

 

[jaxnjil]

Re: Inboard vs. IO

So far the winner is still IO. I completed an initial inspection and am leaning towards a 2003 Rinker 270 Fiesta Vee with single Merc 350 and Bravo 3 with two counter rotating props. Anyone familiar with this drive/prop set up?

not on the water quite yet but can tell you what it took to swap an A I to a BIII as well as the cost

 

[TilliamWe]

Re: Inboard vs. IO

My father owned a Chaparral Signature 27 with the 350MAG MPI/Bravo 3. It did a good job. No rocket by any means, but a good job. If that 350 is just the 250hp carbureted version, I would say the boat could be underpowered. If it's the 350MAG MPI, then it's 300hp and it would be a good match.

You need to sea trial the boat with your anticipated load aboard. That way, you'll know if it has the power to do what you need it to do. Pay very close attention to the WOT RPMs. Since Bravo 3 propsets are over $1000 new from Mercruiser, and usually over $350 on EBay, changing props is not easy. Plus it takes a special prop wrench or two, depending on what you like.

Check the drive very closely for corrosion. And I mean have the props removed to check the rear bearing carrier too. That's where the corrosion would be the worst, and that's where it causes problems.

Good luck.

 

[Lou C]

Re: Inboard vs. IO

NO GIN is in salt water Long Island NY....anyone will tell you if you keep an I/O in the water here...it's gonna be work...no doubt about it...and for sure if you intend to buy another one...try to get one that was not left in the water and maintained well or one that is just a few years old so the salt water issues have not caught up with it yet....I have kept my '88 Cobra I/O running well in salt for 7 seasons but I do all the maintenance...every year...and things that need fixing get fixed right away...
The other option is an outboard in the 200 hp range...the OB is more epensive yes but still gives you tilt n trim and easier manuvering that the I/O has...the straight inboard is the simplest...cheapest to repair (sometimes the engine access can be poor) but least efficent...can't trim up prop and manuvering with a single inboard is more difficult....

OBs are a lot easier to re-sell around here than I/Os esp after they are a few years old...but I am OK with I/Os cause I can do much of the work myself...

 

[HT32BSX115]

Re: Inboard vs. IO

So far the winner is still IO. I completed an initial inspection and am leaning towards a 2003 Rinker 270 Fiesta Vee with single Merc 350 and Bravo 3 with two counter rotating props. Anyone familiar with this drive/prop set up?

Yeah, it's a pretty good setup. If you're going to moor it in salt or brackish water you need to have the electronic corrosion prevention system professionally set up and checked to ensure that it's working correctly.

The service manual and subsequent Service bulletins describe the procedures etc.

The performance of the Bravo III is great and correctly taken care of, there's nothing wrong with them.

My 87 211 Liberator with the original 340HP single prop OMC King Cobra while fairly fast at top speed was a real DOG out of the hole and getting up to plane.

After after I installed the 1997 330hp 454 & Bravo III, and while I lost a few top speed MPH, it now just ROCKETS out of the hole. (I took the original (new) owner <my brother> for a ride and he couldn't believe how well it launches and accelerates with the B3. It made a huge difference.


I think you'll like it.


Cheers,

Rick

 

[arks]

Re: Inboard vs. IO

OK, I'll chime in here.
My previous boat had an Mercruiser M (pre-Alpha) I/O and the damn thing caused me much frustration over the 18 years I had her. I had to replace a gear, seal, or bearing just about every year I owned that boat. The towboat operator was becoming my friend! I eventually put a brand new Alpha outdrive on her but was so sick of it I sold the boat
.
When moving up it was a no-brainer- I went with straight-shaft inboards. So far after 5 seasons- absolutely NO maintenance issues. Yes, I'm more careful about water depth but here on the Chesapeake we have mostly mud or sand bottoms so it's not a huge deal if you touch lightly. Also, I keep the boat in a wet slip year-round.

To each his own, I guess.

 

[TilliamWe]

Re: Inboard vs. IO

Other than being outdrives, Alphas and Bravo are nothing alike. So your maintenance issues on a boat 25 years ago has little bearing on this guy's post.

 

[Lou C]

Re: Inboard vs. IO

Going back to the original poster's question....I can say if you are leaving it in the water...corrosion is NOT the only issue....in salt water you can get barnacles and other nasties...which can actually cut trim lines and the bellows on an I/O....and the antifouling paint that is sold now...never works the whole season...so you will have to either pull the boat out mid season and clean it and re-paint...(also a good time to replace the anodes and check the gear oil) or anchor the boat in shallow water...tilt it up....and scrape away with an ice scraper...

And as far as repairs I've had to do to the drive...bellows...gimble...trim lines...bearing retainer (corrosion) and various seals...but when I bought this boat it was 14 years old...some bearings and seals had been replaced in the drive before I bought it....now it's 21 years old and still shifts great and is quiet..no problems other than the marine growth issues....so I/Os can be run in salt and moored in salt...there are many in my harbor...typically bowriders and the smaller cruisers...but the owner really has to be serious about the maintenance...and although many will say go OB for a smaller boat...or twins on a bigger one (the Coast Guard boats have twin Honda 225s on them....the Tow Boats have single Suzuki 4 strokes on them)...if you have a problem....you better have a good mechanic and they have to have access to all the diagnostic software the manufacturer puts out to fix problems...and the cost of parts is typically higher than those for an IO...and not so easy for the driveway mechanic like me to work on....

 

[NoGin]

Re: Inboard vs. IO

Thanks for all the great information guys. The war on Inboard v. Outboard v. IO is evident and seems can be debated all day long! After reading through all the posts yet another time I think the most important variable everyone has touched on is location. LOCATION, LOCATION, LOCATION!!!

I am on the North shore of long Island in the LI Sound. Salt water with horrible growth problems. It's no doubt that here IO needs to be maintained very well and always checked. This is where I went wrong on my Thompson with the twin 3.7s and Alpha ones.

It is also obvious that the newer IOs are built far better than the older ones. However, perhaps with an owner that doesn't take his eye off his older gear (in my case, alpha 1's) he will be just fine.

I am almost 100% that found the boat I will be moving up to; 2003 Rinker 270 Fiesta Vee with 350 Mag Vortec FI with Bravo III drives. Although I don't need to sell my Thompson prior to buying the Rinker it would most certainly help! Anyone interested she is in NY Craigslist. Just type in Thompson 290.

...... However in the back of my mind there is always the chance I may just keep her for next year and really stay on top of the maintenance! Would certainly be cheaper than a new Rinker!!!