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AQ series single prop propshaft

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murfman

Regular Contributor
What is the interchangeability of the propshaft on the AQ series drives? I am considering a project to make new shafts that would use the common Mercruiser spline size allowing the use of modern prop technology and the ease of getting a replacement quickly. I just want to know if there were major differences between the 270-280-290 and SP shafts internally. Once it is past the last seal it would be the same dimensions as a Mercruiser outdrive. Thanks in advance Murf
 
The 250, 270 and 275 prop shafts are of a different over-all length from the 280, 290 and SP.
However, when the correct spacer/line cutter is installed, all of these shafts net the same length of exposed splines.
In other words, there's actually NO long or short shaft as some speak of.
(this is very commonly misunderstood)

FYI, the amount of work, tooling, material needed, hardening, chrome finishing, etc, will quickly make this idea very non-cost effective.

If you are going through propellers often, you'll do better if you were to find a great multiple purchase deal, and stock up on AQ series props!


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Props are like gas for me. I expect to have less of it when I get back. I just figure a hundred bucks into the cost of any trip for a new prop. A good reason to stay with aluminum. One day I may take them all in for rebuild at once in hopes of getting a wholesale price for repair - I've got 5 that need work. Here's how I fit the cheap prop on my 250 drive.
http://tinyurl.com/o9j4sfu
 
Last edited:
RicardoMarine said:
The 250, 270 and 275 prop shafts are of a different over-all length from the 280, 290 and SP.
However, when the correct spacer/line cutter is installed, all of these shafts net the same length of exposed splines.
In other words, there's actually NO long or short shaft as some speak of.
(this is very commonly misunderstood)

FYI, the amount of work, tooling, material needed, hardening, chrome finishing, etc, will quickly make this idea very non-cost effective.

If you are going through propellers often, you'll do better if you were to find a great multiple purchase deal, and stock up on AQ series props!


.
Click to expand...
I was led to believe that at least the 250 series had a smaller diameter shaft. Not on the prop end, but internally.

I know that back in the 1980s there were shafts made that used Merc props but they are long gone now.
 
I have connections at machine shops, specialty steel suppliers, players, and heat treating shops all around Chicago through work. I do industrial controls, and calibrations for a living. I might be able to pull some strings to get a run of these made.
 
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murfman said:
I was led to believe that at least the 250 series had a smaller diameter shaft. Not on the prop end, but internally.
The 250 lower units used bevel cut gears, of which may have caused the internal portion of the 250 shaft to be different.
270 and later are all hypoid cut gears.
270 and 275 are similar........ 280, 290 and SP are in the same category with one another, but are not the same as the 270/275.

Given my access to V/P parts, I've never tried to interchange these shafts.

I know that back in the 1980s there were shafts made that used Merc props but they are long gone now.
You may be getting some erroneous info.
The short hub prop that would fit the 250 will also fit up to the SP drive.
IOW...... early 70s through early 90s.
Click to expand...
 
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These shafts were made in 2 styles, stock Volvo prop, or Mercruiser prop splines.
 
Run yours 500-1000 hours a year and get back to me on that ;)
Plus winding up buoy line in a DP has way more potential for expensive damage than a SP , last time it was $4,100.00 :(
It's just my experience from 34 years of fishing.
 
The advantage of the Duo Prop is far too excellent for me to give them up.
I'd use those 34 years of experience and would avoid those dang buoy lines. :D


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Sometimes the crab pots are close together, crazy crowded, it doesn't matter how good you are or how many years experience, everyone winds up line now and then. And it is NOT floating line. No crowd usually means no crab$. Gas engines stall quicker when winding up line, usually causing no damage.
 
My core Mercruiser shaft showed up today, I am going to pull apart my spare lower unit and take the shafts to a couple machine shops this week. I will figure out pricing and let you know.
 
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