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Old 06-06-2008, 06:09   #1
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2 stroke vs 4 stroke? Shaft length?

Hi all,

I know this issue has been discussed in previous threads, but in the past, it wasn't always clear whether the 2s vs 4s discussion pertained to dinghies or small sailboats...

We have a 1978 Watkins 27. This spring we blew the piston rings on our 30+ yr old Yanmar (diagnosed with the help of this community), and after a spring of evaluating our options, we've decided to chuck the inboard overboard and repower with an outboard. So now we are ready to ask or next set of questions:

We have heard 4 strokes are quieter than 2 strokes, but also that they are heavier. What do people prefer and why?

How long is a "long" prop shaft? For a transom mount, what do people recommend?

Thanks!

Erika and Ryan (WilmingtonPiper)
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Old 06-06-2008, 06:21   #2
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How long is a "long" prop shaft? For a transom mount, what do people recommend?
Not so sure there is a difference in the length of the prop shaft, but rather the drive shaft.

Normally you choose the 15 inch version for dinghies and the 20 or 22.5 for sailboats.

4 Strokes are heavier and expensiver, but will use less gas (pretty important these days with gasoline pushing $5.00 per gallon and much more in the islands)

A 9.9 HP will probably be all you need....
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Old 06-06-2008, 06:39   #3
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For your purposes I think a 4 stroke would be better. Quieter, more fuel efficient and most probably you can get it serviced where you sail. For a dinghy out cruising I would still go for a two stroke, lighter and easily serviced most anywhere.
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Old 06-06-2008, 08:36   #4
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Your shaft length will depend upon the distance from the top of the mounting bracket (in deployed position if adjustable) or transom, to the waterline.
Shorts shaft = approximately 15"
Long shaft = approximately 20"
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Old 06-06-2008, 08:51   #5
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Assuming you are powering a sail boat, there are mounts that swing up so that your not dragging the prop through the water while sailing. These often get the motor low enough when in use that you can use the short shaft.

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Old 06-06-2008, 14:59   #6
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On my Catalina 27, the pervious owner enclosed the original outboard well and added a drop down bracket to allow the motor to be tilted completely out of the water. They had a long shaft but it was to deep in the water when running and caused a lot of excess drag. Take your time and measure carefully when you set the bracket to avoid this, it really takes away from the ability of the motor to power the boat.

Also, reaching over the back to throttle and switch from FWD to REV is a pain, I highly recommend the remote throttle / gear selector. You can probably get a 4 stroke w/ electric start that can be wired to charge your batteries as well.

For it to be user friendly, $150+ for the bracket, $1000 for a used 9.9, $200 for the controls + labor......



How much is it to have the inboard repaired again?
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Old 06-06-2008, 15:08   #7
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