I/O (Sterndrive) Conversion to Outboards

[airshot]

Very personal decision based on health, age, retired or not, etc. One thing we can't change is time and it is indeed marching on. Tasks that I was exited about learning/doing 20 years ago now seem daunting. I'm finding the older I get the more the moon/stars have to line up before the boat goes out. Is downsizing not an option? Drop to a single, many greats boats out there in that category. What you think you have to have now may not be so in 5 years.

Life changes in a flash, live life to the fullest as long as you can afford it ! When we retired, we bought a used motor home to try it out....was great for the first two years, started looking at newer units and downsizing our home. Within a few months my wife had two hip replacements then two back surguries....non her fault.. Shortly after can barely walk, motor home sat for 18 months then gave up and sold it. Downsized the boat as she can no longer handle any wave action with her back. So....life can change in an instant, enjoy while you can !! Just a small 16' fishing boat to keep fish in the freezer. Only travel for us are trips to the doctor....

 

[Scott06]

Owner reviews on the Suzuki 300/350 duo-prop outboards seem to be OK. One thing that jumped out when looking at the spec's is that the 350 has 12:1 compression while the 300 has 10.5:1. So, I guess they are getting power from the compression as the blocks are the same displacement (267 Cu in) IIRC. Got to burn higher octane fuel in the 350's.

Just wondering if I can be OK with the 300's and use 87 octane gas. Most of the alternative boats that I looked at and of similar weight had twin 300's.

These are direct injected i would assume. since the timing of injection inhibits detonation they can use really high compression ratios again. Always a lot of discussions on compression on the muscle forums I am on. One of the engine builders mentioned difference between 9.5 and 11:1 compression is only like 3% or 4 % more power. So basically he was saying no sense pushing it for a few more ponies. Of course this is old school carbed engines.

i wonder if direct injected OBs suffer carbon build up on th intake path and valves like automotive engines do? this might negate some of the Maintenace savings of switching. What does the rough math on this workout to? Would think it would be half of the boats cost if not more to swap?

 

[Pmt133]

These are direct injected i would assume. since the timing of injection inhibits detonation they can use really high compression ratios again. Always a lot of discussions on compression on the muscle forums I am on. One of the engine builders mentioned difference between 9.5 and 11:1 compression is only like 3% or 4 % more power. So basically he was saying no sense pushing it for a few more ponies. Of course this is old school carbed engines.

i wonder if direct injected OBs suffer carbon build up on th intake path and valves like automotive engines do? this might negate some of the Maintenace savings of switching. What does the rough math on this workout to? Would think it would be half of the boats cost if not more to swap?

If the intake and PCV system is set up correctly, there should be minimal build up in the intake/valves on a DI engine. When I pulled my intake to replace my plugs at 100k (yes you read that correctly, stupid design) there was nothing much to note in there. Looked the same or better as any port injected engine I've had apart with that kind of milage. I know it's not typically the case but my experience is good. The ole Italian tune up helps too.

 

[tpenfield]

I'll probably price-out 3 engine options. Mercury, Yamaha, Suzuki and see how it all compares.

In 300 HP options The Merc is a V8, the Yammy and Zuki are V6
In 350 HP options, The Merc is a V10, the Yammy and Zuki are V6

IIRC, The Yammy used to be a V8 in the 350 HP range, but now they have bumped their V6 to 350 HP.

Yammy are the lightest engines and Zuki's are the heaviest.

Not sure any of the motors are supercharged . . . (any more like the old Merc Verado (L6) . . . probably a warranty repair item ? )

 

[Scott Danforth]

My former boss's boat has twin Suzuki 250's. Other than ECM issues, they have been ok.

 

[Stinnett21]

Also, I noticed that Suzuki now has dual prop lower units available on both the 350 and 300 HP versions. Just wondering about that vs. the single prop that the Merc and Yammy would have. It seems like Suzuki is making a strong play in the re-power market.

Others know more than me at this level but it seems having duo props on a twin installation would make no sense.

 

[tpenfield]

It is beneficial on heavier boats. That is why you see many twin engine boats with the Bravo 3 and the Volvo DX series outdrives. Now it looks like the outboards are getting in the game, since many boats that came with I/O are now going outboards.