I/O (Sterndrive) Conversion to Outboards

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,828
Holiday Update . . .

I hope everyone is having an enjoyable Holiday season. We hosted Christmas and the kids/grandkids have been staying with us for the week.

Fiberglassing has been on hold while the family is here to avoid the possibility of fumes in the house. Meanwhile . . .

1) I have been continuing to clean-up the outdrives of the 'old' motors, using the non-caustic paint remover. It works pretty well.

2) I also have looked into the engine choice and the Dometic Seastar Optimus stuff, which is all the high-tech electronic controls the the boat will have. As I gather information it looks like the Suzuki motors may be the easiest to integrate. I was leaning towards Mercury, but I keep running into potential gotchas on the compatibility of Mercury controls with the latest & greatest Optimus components. It seems to me that Mercury is more geared to the OEM market with their JPO, and not as easy to deal with in the aftermarket. ( let me know if I have the wrong impression :unsure: )

If I went with Yamaha, it would be all the Helm Master EX stuff. Pricing and convenience will tell the story.

One nice thing I found was that Optimus has a Bill-of-Material generator on their website, which has been helpful in understanding the components needed and the cost.

3) I'll be interested to see how the final 2025 figures on the boat market look. It seems that things have slowed down for boat sales in general, and I'll be interested to see how the outboard figures look. (hoping to get a good deal on the engines, which ever brand I choose).

4) My project schedule is sliding a bit, given the winter temperatures. I was originally hoping to be sending the boat off for re-power in the Feb/March time frame, but that may be more like April.

Anyway, I'll be back at it doing the fiberglassing after New Years.

Wishing everyone a happy & safe 2026. 🍾
 
Last edited:

redneck joe

Supreme Mariner
Joined
Mar 18, 2009
Messages
14,008
As I age and deal with every more of my stuff breaking down I'm leery of all things electronic. My newest car is a 2026 and it does crazy crap occasionly that can never be replicated at the shop. With steering, I want a more manual approach. Keep telling my wife I just want a mid 70s Ford truck with a straight six and a clutch. After we get settled in new house might have to resume that search.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,821
049.JPG056.JPG
I like inline 6s too, especially AMC/Jeep ones. I want to restore my old '98 Grand Cherokee because the new ones just ain't the same.
Inline 6, not a powerhouse but reliable and very easy to work on.
shift it yourself transfer case, no wiring, no actuators no fault codes, plus on the Selec-Trac case you have a useful full time 4x4 setting, great for winter driving.
live axle suspension where you can change 4 shocks in an hour, instead of dealing with spring compressors etc with the modern IFS.
and you still have EFI and ABS!
that's an old pic, it was at 96,000 then now it's only at 183,000 not too much for a 4.0 six.
We have owned it since new; I did every oil change, driveline oil change tune ups and brake jobs. VERY easy to maintain. Not like today's horror shows where it takes hrs to replace a headlight bulb. The only jobs I paid for were to pull the dash to replace the heater core and AC evaporator.
I do love my 07 Grand with the 5.7 Hemi but every single job is harder, more difficult or expensive to have done. It is FAST though!
 
Last edited:

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
51,884
Nah.... A toaster element on a simple switch is Luddite going back to the 51 patent and the 66 implementation
 

redneck joe

Supreme Mariner
Joined
Mar 18, 2009
Messages
14,008
When did the fuse come into play into the design. My wife tells me I have a hot butt, but not that kind.


Ted, get working to keep us on topic...
 

Pmt133

Lieutenant
Joined
Jan 6, 2022
Messages
1,252
Is there any way you are leaning towards for the repower? I know you have feelers on all 3 but are you leaning one way or the other? Or is it mostly going to come down to cost?
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,828
Is there any way you are leaning towards for the repower? I know you have feelers on all 3 but are you leaning one way or the other? Or is it mostly going to come down to cost?
Probably going to come down to a combination of cost and convenience. All things being equal, I'd go with Mercury. But, I doubt things will be equal . . . :ROFLMAO:

Also, I have a couple of upholstery jobs to 'squeeze' into my schedule. Customers from the past few years, coming to me with some follow-on work.
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
7,322
Probably going to come down to a combination of cost and convenience. All things being equal, I'd go with Mercury. But, I doubt things will be equal . . . :ROFLMAO:

Also, I have a couple of upholstery jobs to 'squeeze' into my schedule. Customers from the past few years, coming to me with some follow-on work.
Are you doing the upholstery as a business or side hustle now?
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,828
When I do the Optimus 360 configuration using their website tool (optimusbom.com) I get some notices when configuring for Mercury engines.

Screenshot 2025-12-29 at 1.45.06 PM.png

Apparently, the Optimus does not work with the latest DTS controls, so I'd have to buy a legacy control.

Then there are some Mercury parts to get to make it all work, which could add about $4K.
.
Screenshot 2025-12-29 at 2.04.09 PM.png
.
The Suzuki and Yamaha configurations come up cleaner.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,609
Hey Ted, as a Mod you could delete all these non-conversion comments and clean up the thread ;)
 
Top