2.3 omc tko 3.0 outdrive wot 2300 rpms

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alex2626

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i have a 2.3 omc tko with a 3.0 15 tooth outdrive it wont pass 2300 rpms wot its a 17 foot sunbird help
 
86 century

86 century

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

The gears are different in the drives for those engines don't have my manual handy right now..
Tomcat did some funny stuff with the gears for the 2.3 in different years the upper and lower may be differnt
 
Howard Sterndrive

Howard Sterndrive

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

yeah, #6 on this list stands out because I'm not sure the 15 spline propshaft drive was ever mated to the 2.3 originally
http://forums.iboats.com/showthread.php?t=295070

edit - and now I see the 3.0 part - definitely a different overall gear ratio. not sure if there is any hope for correcting it by changing to a different pitch prop.

I suppose you could drop pitch as much as possible. I think there was an 11P on the low end. certainly there was a 13P. I suspect an 11P would be pretty lousy at higher speeds though.
 
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alex2626

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

can i change the lower unit to a small gear 3.0 with a 13 tooth spline and would it work
 
Howard Sterndrive

Howard Sterndrive

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

no, the 2.3 had a unique lower and upper ratio

the 3.0 is a torquey long stroke 4, revving to 4500 only
the 2.3 is a screamer - high rpm engine revving to 5400

what pitch is your propeller?
 
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alex2626

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

Howard Sterndrive said:
no, the 2.3 had a unique lower and upper ratio

the 3.0 is a torquey long stroke 4, revving to 4500 only
the 2.3 is a screamer - high rpm engine revving to 5400

what pitch is your propeller?
Click to expand...

14.8x17
 
Howard Sterndrive

Howard Sterndrive

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

I'd try a 13P prop

iboats also sells 11P to fit your drive, a Solas and a Quicksilver -but there is no exact science here... it's trial and error
or get the correct drive

the issue with props is the loss of efficiency out of the usual 15 to 23 pitch range
 
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alex2626

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

Howard Sterndrive said:
I'd try a 13P prop

iboats also sells 11P to fit your drive, a Solas and a Quicksilver -but there is no exact science here... it's trial and error
or get the correct drive

the issue with props is the loss of efficiency out of the usual 15 to 23 pitch range
Click to expand...

can i replace the lower with a 2.3 lower and leave the upper the same and change the prop
 
Howard Sterndrive

Howard Sterndrive

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

if you have a 2.3 drive, just use that.
You'd want to look up the gear ratios and do the math on overall -that combo might be a worse ratio than what you have. You could get a Seloc manual and a calculator and work out the different combos of upper and lower.
If the 2.3 drive upper failed, you will need to rebearing/reseal the lower at minimum, and I'm not sure of the mix-n-match capability of all the lowers and uppers year to year.
..maybe.
 
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alex2626

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Re: 2.3 omc tko 3.0 outdrive wot 2300 rpms

Howard Sterndrive said:
if you have a 2.3 drive, just use that.
You'd want to look up the gear ratios and do the math on overall -that combo might be a worse ratio than what you have. You could get a Seloc manual and a calculator and work out the different combos of upper and lower.
If the 2.3 drive upper failed, you will need to rebearing/reseal the lower at minimum, and I'm not sure of the mix-n-match capability of all the lowers and uppers year to year.
..maybe.
Click to expand...

yeah i have a lower the lower on the modern 3.0 is 14.26 ratio and the 2.3 13.26
 
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