I/O (Sterndrive) Conversion to Outboards

Lou C

Supreme Mariner
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Nov 10, 2002
Messages
12,652
Agreed and you don't have the following concerns:
sudden freeze destroys your engine because you couldn't get to it, happened to thousands across the South a few years ago, we Northerners are used to that inconvenience
fuel vapors in the bilge hazard
gimble/ujoints issues if you wait too long to change your bellows
no risk of a catastrophic transom failure if you let noises from the gimble or ujoints go too long...you can trim the OB up in shallows without worrying about the ujoints complaining...
Leaky Mercruiser steering arms corroding, etc....
Regular and expensive exhaust manifold & elbow replacement in salt water (5-7 years like clock work), I have 5 years on the current set, and if these need replacing, that's exhaust #4 (2004, 2011, 2017/18). Keep in mind if you're doing the whole works, even at aftermarket prices $900 parts (now) with OEM (1.5x that aftermarket price) and labor forget about it. So far just for parts, I am in for close to 2 grand for my exhaust maintenance over the years (those were all pre-Covid, government spending spree prices)
Ever price an I/O exhaust with cat converters, well, you used to be able to buy a fully dressed engine for that price! ($6500 parts, labor extra).
The older you get, the more OBs make sense even if you got to take out a loan to buy one lol.
 

Dubed

Petty Officer 1st Class
Joined
Sep 3, 2021
Messages
373
I was swearing last weekend about just wanting a simple Center Console with an outboard. I was changing fuel filters, laying on my side, hanging in the bilge, trying to remove my water separator (which wouldn't unscrew). Ended up having to remove the alternator and bracket, the bilge pump and hose, just to access the filter. Yeah, an OB would be just fine for my 63 year old body
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,424
OB's are not going to be 'easy street' by any means, after all it is still a boat.

More boats are coming out with decent swim platform designs around outboards, whereas 10 years ago it was pretty much non-existent. For me it has the following advantages:
  • no anti-fouling on the lower unit . . . (prop efficiency)
  • although the engines would still need work, stuff should be more accessible.
  • get closer to shore . . . traverse skinnier water.
I've had Sterndrives (I/O) for 20 years. but . . . I think my needs are changing in the direction of OB's
on larger boat like yours I could give up swim deck space because there is more seating/lounging area. On a 21 ft the swim deck is prime real estate.

All of it is a far cry from the old days - I remember stepping on the outdrive to get back in out neighbors boat (1969 Starcraft IO- 18 ft) didnt have a swim ladder/ the opposite of a walkthrough stern

the skinner water aspect is nice
 

Scott06

Admiral
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Apr 20, 2014
Messages
6,424
Prepaid Service agreements and extended warranties are cash cows for Service departments....lol

Buying either is foolish at so many levels....
Never bought one either for the same reason, just using it as an indicator of reapair costs
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,652
Head over to a Merc or Volvo parts site and check out what they want for parts for I/Os now. Hint, it ain't the old days of GM base engines, Delco EST distributors, and Holley or Weber/Edelbrock carbs.
 

dingbat

Supreme Mariner
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Nov 20, 2001
Messages
16,071
just using it as an indicator of reapair costs
Warranty pricing is calculated as a percentage of manufacturers cost and/or MSRP.

Indicates nothing other than a new high HP outboard sells for more than the other two offerings.
 

tpenfield

Moderator
Staff member
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Jul 18, 2011
Messages
18,039
I've listed my CY 338 for sale in a couple of places . . . Still got to do a couple repairs. As a final improvement project, I installed the TV that I had sitting in the closet for the past 3 years. :ROFLMAO:

2016-cruisers-sport-series-338-bow-rider-711139-20240905103303417-40_XLARGE.jpg
 

Scott06

Admiral
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Apr 20, 2014
Messages
6,424
There is truly no free lunch, one thing to keep in mind is that in the last 15 years engine tech on sterndrives has become much more complex and expensive, parts cost isn't much less than outboards, and due to ridiculous designs coming out of the sport boat makers, access is worse than ever.
I/Os made sense and were tolerable for me when:
1)outboards were loud, smokey and not too reliable
2)sterndrives had simple carbureted engines, cheap & simple to repair
3)sport boat design lent itself to more accessible engine compartments, without "improvements" like 'glassed in rear seating areas, or walk throughs that make the engine compartment even smaller (and the geniuses manage to put it on the side where the small block Chevrolet starter is, making that job nearly impossible).
The boat that my brother just traded, was a really nice running boat but a future maintenance nightmare, and I told him so. Having to pull the engine because Chapparal can't design it to allow you to change a starter, unclog Merc's single point drain, or God forbid, change a steering actuator, is a no-sale for me.
We are going to water test the Chap he bought with the outboard out on the Great South Bay this weekend, should be fun.
Your brothers old boat had the 4.5/250 hp correct ? How did that do in a 20-21 ft boat .

My current boat is 21 ft with a 5.0 with 4 bbl edlebrock on paper 260 hp… like the size but when I have 8 ppl one of which is one the rope wondering if 4.5/250 hp cuts it
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Hey Ted ..... You do boats like I do hotrods..... Sell them just as you finish them, and get the next project
 

Lou C

Supreme Mariner
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Nov 10, 2002
Messages
12,652
Your brothers old boat had the 4.5/250 hp correct ? How did that do in a 20-21 ft boat .

My current boat is 21 ft with a 5.0 with 4 bbl edlebrock on paper 260 hp… like the size but when I have 8 ppl one of which is one the rope wondering if 4.5/250 hp cuts it
It was actually the 200 hp 4.5. Plenty of power, prob the equal of at least the 5.0 V8, partly to to somewhat less weight. Very smooth easy starts steady idling even the dog clutch Alpha seemed a lot more refined than in older models. Except for the lack of access for anything beyond oil changes & draining the water out (while it works!) a very pleasant power package. It’s a shame that the boat makers have such little regard for the serviceability of the power package…
 

Pmt133

Chief Petty Officer
Joined
Jan 6, 2022
Messages
568
Wow this thread was a ride. :oops:

I think all this really highlights is the need to have more than 1 boat. If I could afford 1 more I would. :LOL:
 

tpenfield

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Jul 18, 2011
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Quick Update . . .

The Admiral and I have been discussing the various options of either converting the boat (to OB's) or doing the sell & buy thing. It looks like neither is a straight path. . . it is very silent on the boat selling front (so far).

Also, I would miss the full cabin that the CY 338 has, so that may be calling me back to working with what I have.

We are doing an overnight this coming weekend, which we have yet to do with this boat. (It seems like Covid got us out of the habit). Anyway, we will see how that goes with the smaller cabin.

At any rate, we got a bunch of other stuff (other than boats), over the next year that will keep us busy, as we slide into retirement :D . My plan is to do some additional research over the winter and re-visit the idea of an OB conversion next year.
 

tpenfield

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The boat is out for the season . . . The 'plan' is to run it as I/O powered and then start an outboard conversion next year at this time.
 

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flashback

Captain
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Jun 28, 2002
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3,963
Yes, the boat is better than I had thought it would be for over-nighting. So, it's a keeper.
I thought that might be the case, one too many got under your skin, I can't blame you, it's a sweet ride and you'll get the fun of making it yours...
 

tpenfield

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I thought that might be the case, one too many got under your skin, I can't blame you, it's a sweet ride and you'll get the fun of making it yours...
Yes, I am working up the design for an extension/bracket. There should be plenty of time over the next year to figure stuff out. :unsure:
:geek:
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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will the bracket be stepped? recessed for tabs? 2 or 3 motors? with or without hydraulic jack plates? Integral swim ladders? Folding swim stairs?
 
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