Αre outboard engines lighter than other motors?

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Offline peppercorn

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Αre outboard engines lighter than other motors?
« on: 02/03/2010 12:15:16 »
If I wanted a lightweight engine with only a dozen horses or so, running fixed high rpm, would an 2nd hand outboard be a good bet?
« Last Edit: 03/03/2010 23:18:51 by chris »

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Offline graham.d

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Re: Αre outboard engines lighter than other motors?
« Reply #1 on: 02/03/2010 13:03:22 »
You can buy small engines as part of a generator or pump or (probably) for general use. An outboard is very specific to turning a propellor sitting in water so you would have bits you don't need and a rather inconvenient modification to get the rotary power out and into whatever you want to drive. Even a lawnmower engine would be more convenient I think.

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Offline peppercorn

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Re: Αre outboard engines lighter than other motors?
« Reply #2 on: 02/03/2010 13:07:10 »
What if lightness is key though?  I also think a o/p shaft speed from a outboard would be a good match for the large alternator I have in mind.

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Offline graham.d

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Re: Αre outboard engines lighter than other motors?
« Reply #3 on: 02/03/2010 13:29:43 »
I don't know whether outboards are in lighter than a general purpose engine but I doubt it, and it would not be very convenient to modify. Try Briggs and Stratton, Honda or any of the numerous small, general purpose engine manufacurers. Some outboards are VERY heavy by the way and, I can confirm, even the lightest are not that easy to lower from a boat onto a dinghy :-)

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Offline LeeE

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Re: Αre outboard engines lighter than other motors?
« Reply #4 on: 02/03/2010 13:59:22 »
I think the only concession to lightness in outboard motors are that they're capable of being lifted and carried (but not that it should necessarily be easy to do so, otherwise they'd all be pinched).

I'd suggest instead, that you look at the small IC motors fitted to hand-held power tools, such as strimmers, for very low power, or chain-saws if you need something a bit beefier.  Your cheapest option may be to use a 49cc moped engine from a breaker's yard though (and I'd imagine that they're probably designed for longer running times than a typical power tool motor).
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Offline Karsten

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Re: Αre outboard engines lighter than other motors?
« Reply #5 on: 03/03/2010 21:52:20 »
Outboard motors also rely on water-cooling. Old lawnmower motor might be another option. Simple, light, air-cooled.

Here is a generator built with a lawnmower:
http://www.webpal.org/b_recovery/3_alternate_energy/electricity/lawnmower/generator/generator.htm
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