# Help With Small Engine

**URL:** <https://boards.straightdope.com/t/help-with-small-engine/724890>\
**Category:** In My Humble Opinion\
**Created:** [July 11, 2015, 10:01pm UTC](https://boards.straightdope.com/t/help-with-small-engine/724890 "2015-07-11T22:01:11Z")\
**Posts on this page:** 13\
**Page:** 1

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**Author:** ![Dego](https://avatars.discourse-cdn.com/v4/letter/d/ec9cab/32.png) [@Dego](https://boards.straightdope.com/u/Dego)\
**Post date:** [July 11, 2015, 10:01pm UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/1 "2015-07-11T22:01:11Z")

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I have a Weed Eater 500 (mower) would like to put this motor on a scooter.  
The scooter has a weed wacker engine already on it. Any tips on the project would be very appreciated.

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**Author:** ![jimbuff314](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@jimbuff314](https://boards.straightdope.com/u/jimbuff314)\
**Post date:** [July 11, 2015, 10:08pm UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/2 "2015-07-11T22:08:26Z")

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Reported for forum change.

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**Author:** ![jimbuff314](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@jimbuff314](https://boards.straightdope.com/u/jimbuff314)\
**Post date:** [July 11, 2015, 10:13pm UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/3 "2015-07-11T22:13:12Z")

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Hi, **Dego**. Welcome to the Straight Dope Message Board. This ATMB forum is for questions relating to the message board software or moderation. I notified the moderators to move your question to where it is more likely to get a response. A moderator will be along shortly to do this. Again, welcome to the SDMB!

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**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\
**Post date:** [July 11, 2015, 10:29pm UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/4 "2015-07-11T22:29:41Z")

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Moved from ATMB to In My Humble Opinion.

**samclem** , moderator

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**Author:** ![Nefario](https://avatars.discourse-cdn.com/v4/letter/n/59ef9b/32.png) [@Nefario](https://boards.straightdope.com/u/Nefario)\
**Post date:** [July 12, 2015, 12:31am UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/5 "2015-07-12T00:31:43Z")

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The complexity of adapting a vertical shaft rotary mower engine is quite a project and if you accomplish this, its carburetor and oiling system may not be happy in a horizontal shaft position. You’d be better starting with a horizontal shaft engine. Harbor Freight imports some small engines that may affordable for a hobby project.

Basically, if you have to ask, this project’s not for you. :dubious:

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**Author:** ![AnaMen](https://avatars.discourse-cdn.com/v4/letter/a/dfb087/32.png) [@AnaMen](https://boards.straightdope.com/u/AnaMen)\
**Post date:** [July 12, 2015, 12:44am UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/6 "2015-07-12T00:44:28Z")

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> [@Nefario](#):
>
> Basically, if you have to ask, this project’s not for you. :dubious:

Er, what? Are people only supposed to do things they already know how to do?

It’s not terribly complicated. You put a gear on the shaft, one on the rear wheel motor, add a bike chain and run a throttle cable to the handlebars.  
Not that those are complete instructions by any means, but the weedwacker motor should be fine, as people do this often.

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**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\
**Post date:** [July 12, 2015, 1:38am UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/7 "2015-07-12T01:38:52Z")

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> [@AnaMen](#):
>
> Er, what? Are people only supposed to do things they already know how to do?
> 
> It’s not terribly complicated. You put a gear on the shaft, one on the rear wheel motor, add a bike chain and run a throttle cable to the handlebars.  
> Not that those are complete instructions by any means, but the weedwacker motor should be fine, as people do this often.

no, **Nefario** is right. a weedwhacker engine is probably two stroke, with a horizontal crankshaft (crankshaft parallel to the ground.) he wants to put a push mower engine on the scooter, and those are almost always four stroke and have a vertical crankshaft. and since the push mower engine most likely has a splash oiling system, changing the engine’s orientation is a good way to kill it quickly.

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**Author:** ![AnaMen](https://avatars.discourse-cdn.com/v4/letter/a/dfb087/32.png) [@AnaMen](https://boards.straightdope.com/u/AnaMen)\
**Post date:** [July 12, 2015, 1:49am UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/8 "2015-07-12T01:49:56Z")

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> [@jz78817](#):
>
> no, **Nefario** is right. a weedwhacker engine is probably two stroke, with a horizontal crankshaft (crankshaft parallel to the ground.) he wants to put a push mower engine on the scooter, and those are almost always four stroke and have a vertical crankshaft. and since the push mower engine most likely has a splash oiling system, changing the engine’s orientation is a good way to kill it quickly.

Oh, I see, he is trying to replace a weedwacker engine on a scooter with a lawnmower engine. Yeah, that’s dumb. I was thinking he wanted to change over to a different weedwacker.

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**Author:** ![jimbuff314](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@jimbuff314](https://boards.straightdope.com/u/jimbuff314)\
**Post date:** [July 12, 2015, 2:23am UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/9 "2015-07-12T02:23:51Z")

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I think you may have negated my lovely, warm, welcoming message to **Dego**.

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**Author:** ![AnaMen](https://avatars.discourse-cdn.com/v4/letter/a/dfb087/32.png) [@AnaMen](https://boards.straightdope.com/u/AnaMen)\
**Post date:** [July 12, 2015, 2:31am UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/10 "2015-07-12T02:31:20Z")

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Why build up false expectations about how friendly people are on this board?

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**Author:** ![jimbuff314](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@jimbuff314](https://boards.straightdope.com/u/jimbuff314)\
**Post date:** [July 12, 2015, 3:15am UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/11 "2015-07-12T03:15:47Z")

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I just read the thread about the 3 kids in Michigan, their parents and the judge. I understand your antipathy. I’ve never had children, so I cannot imagine what it must feel like for you to be in such a thread. It’s not worth much of anything, but I’m sorry for your experience there, yesterday and today.

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**Author:** ![AnaMen](https://avatars.discourse-cdn.com/v4/letter/a/dfb087/32.png) [@AnaMen](https://boards.straightdope.com/u/AnaMen)\
**Post date:** [July 12, 2015, 5:41am UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/12 "2015-07-12T05:41:32Z")

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I like to read opposing viewpoints for insight into the thought process behind opinions that seem to make no sense at all. It’s upsetting to think of those poor kids in jail, but things like that happen because someone thinks they are okay. Figuring out how and why could be useful for doing something about it.

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**Author:** ![Nefario](https://avatars.discourse-cdn.com/v4/letter/n/59ef9b/32.png) [@Nefario](https://boards.straightdope.com/u/Nefario)\
**Post date:** [July 12, 2015, 1:26pm UTC](https://boards.straightdope.com/t/help-with-small-engine/724890/13 "2015-07-12T13:26:50Z")

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When I was around 12 - 14 I started building an offroad 3-wheeler based on a tricycle frame turned upside down, bicycle forks, and riding mower rear tires. After watching my efforts for a few months my parents bought me a used Tri-Sport vehicle that my Dad and I rebuilt. But:

- I had a VISION for the drive train.
- I knew how to run most woodworking tools, a metal lathe, and a drill press.
- I could sketch how a 4-stroke engine worked and I had considered a more powerful vertical shaft engine from a collection of junk lawnmowers. I chose a 3HP horizontal mower because I UNDERSTOOD the packaging and/or direction change issues.

So - really - if the OP has a vision of how how this could work I would enthusiastically offer advice in building. But if you don’t understand the fundamental problem - no. “Just put a gear on it” is not a meaningful answer.

Now if this a self-propelled mower with a right angle power takeoff…Hmmm… 😃
