What ratio outdrive for 290

Millhouse

New Member
Nov 12, 2023
15
Boat Info
1998 Searay Sundancer 290
Engines
T-5.7 EFI
I have a recently purchased 1998 Searay Sundancer 290. Powered by EFI 5.7. The Alpha One Gen 2 outdrive look awful and port has big chunk of cavitation plate missing.

Now to the question…. What is the correct ratio? Starboard drive is stamped 162R, Port is not legible(counter rotating) From my research the 5.7 should have the 150 ratio. Any chance it has wrong drives ? Or is it correct since it’s a pretty heavy boat? Any advice would be appreciated! Any thoughts on the SEI outdrives?
 

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What are the engine's serial numbers?

FYI, I think the chunk you're talking about is the anti-ventilation plate. Cavitation is an entirely different thing than ventilation. But it's probably one of the most widely made mistakes in terminology out there!

Engines can be mated to multiple drives/ratios. There is no one "set" ratio. How does the boat perform? Can you get close to your Max RPM? If so, you're good - stop thinking about and go boating :)
 
What are the engine's serial numbers?

FYI, I think the chunk you're talking about is the anti-ventilation plate. Cavitation is an entirely different thing than ventilation. But it's probably one of the most widely made mistakes in terminology out there!

Engines can be mated to multiple drives/ratios. There is no one "set" ratio. How does the boat perform? Can you get close to your Max RPM? If so, you're good - stop thinking about and go boating :)
Thanks! I’m not a boat mechanic so I apologize for improper terminology

Attached is pic of each engine
 

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No worries - as I said, it's a VERY popular mistake!

Can you please clarify the engine serial numbers?
 
It looks like 1.62 to me
 
Mill, as for SEI, my Bravo1 needed a lower half a year ago, mechanic recommended SEI. $1200 vs Merc $3k; 3 year no fault warrant vs 1 year limited warranty. I went SEI and it performed perfectly all summer.
I know a lot of people who use SEI including the towing company at my marina.
They require a 10 hour breakin period and i was told do it religiously and it will last years. Requires a lot of putting around off plane with short bursts of speed. I would definitely go SEI again.
As for ratio, no idea, my mechanic took care of getting the SEI and installing.
 

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I think it says 1.62R right on the tag
 
Mill,
Do SEI over winter. Fortunately, im retired so i would take it out in spring an hour each morning. 10 days and i got thru breakin period. If you still working and have limited time to use boat during week, 10 hours could be 10 weekends. Dont cut breakin short.
 
Please verify - just write the serial numbers in your reply.
. . Engine . . . Drive . . . . Transom
0L025492 . 0L115238 . 0L226738
0L025494 . 0L100336 . 0L225881

Scott, I believe you are correct. Looks like 1.62R to me as well.
 
Thanks to everyone! Definitely appears to be 1.62. So glad to have the lower cost Alphas rather than the Bravo III I have in my other boat. Them bad boys are rotting in front of my eyes.
 
Thank you, Yendor.

This is what the boat was originally spec'd with from the factory and first registered in Ohio:


ENG: 0L025492 4331037LS MERCRUISER 5.7L EFI ALPHA
DRV: 0L115238 5121300LS MERCRUISER ALPHA 1.62:1
TRN: 0L226738 6111001LS MERCRUISER ALPHA TRANSOM



ENG: 0L025494 4331037LS MERCRUISER 5.7L EFI ALPHA
DRV: 0L100336 5111300LS MERCRUISER ALPHA 1.62:1
TRN: 0L225881 6111001LS MERCRUISER ALPHA TRANSOM
 
I'd rather a bravo than an alpha
 

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