Crapsman weedwacker.

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a_dam

New Member
Feb 21, 2009
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Momence, IL
Like I mentioned previously, my brother-in-law had a weedwacker that "wouldn't run right". I told him that I could take a look at it and he said "You can have it. I'm getting a new one". Cool.
That was about six months ago. It's been sitting in my basement. Today I decided to look it over.

Before trying to start it, I noticed something loose. Thought it might be the carb. No. The cylinder (jug) was so loose it would rattle around. Not good.

So I had to partially disassemble the wacker to tighten the jug screws. Went to take off the back half of the plastic cover. The motor's crankcase cover actually IS the plastic cover. There was the connecting rod staring at me. How cheesey is that?

According to Craftsman, this thing is 25cc. But it looks so much smaller than my 25cc Homelite leaf-blower motor. The Homelite is much beefier and better made, I bet. The wacker has only 2 cylinder screws (Homelite has 3). No wonder it worked its way loose.

So I tightened everything up and put her back together. Fired right up and ran good. I did some trimming in the yard for about 20 mins and everything's fine. But now I'm not so sure if I would use one of these motors on a bike. That was my plans for the thing in the first place, but after seeing the quality, I'm having second thoughts. It's a perfectly functional trimmer.

Do other trimmers have sturdier engines than a Craftsman? (model # 358.795531)
 

deacon

minor bike philosopher
Jan 15, 2008
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north carolina
All the weed whackers I used on bikes were lightwights. None of them impressed me as better than another. The ryobi with the 3/8 drive shaft seemed to be heavier but I can't really say that. I shook all of them apart at one time or another. The craftsman I had went out because it was bolted down to the bike wheel and I ran it out of gas. Of course I didn't realize it was out of gas and kept on pedaling waiting for it to start. I waited until it froze up.

In my opinion one is about as good as another. Some guys probably feel differently. I loved my whacker bikes but I moved on since then. For toughness I liked the chainsaw bikes better. Whatever you use watch out for vibrations. They are bike killers. Thats what shook the jug loose. On a mounted whacker it will break the mounting holes in the engine frame.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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Not to mention most have a cantilever crank....(one bearing on one end, instead of the crank being supported at both ends).
 

deacon

minor bike philosopher
Jan 15, 2008
8,114
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north carolina
So very true..... You can use a Weed Whacker but the life expectancy is not great. I think they might work best with a pusher motor where you could put a sprocket on the motor and a scooter wheel on the pusher. I have been thinking about that a lot recently.
 

NEAT TIMES

New Member
May 28, 2008
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I Bought A Bunch Of Wacker Motors On Ebay Motors Auctions. The Older Motors That Have The Rewind On The Other Side Are Built Much Better. Never Did Do Anything With Them. Ron
 

a_dam

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Feb 21, 2009
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Momence, IL
Hey, deacon. I thought you might be the guy with the most experience on this. I figured most brands would be about the same, except maybe for the top-dollar ones like Stihl, Husqvarna, I guess. Probably be hard to find one of those cheaply, even used.

From what I just saw, I would recommend the Homelite over the Craftsman. The Craftsman says 2003 but doesn't look like it saw much use. I don't know how old the Homelite was when I got it. Looked well used and the fuel lines were deteriorating. But I put about 2000 motor miles on it last year and expect to put a couple more on this year - fingers crossed.

The aluminum mounting flange on the Homelite is a lot sturdier as well, but I wouldn't think of relying on that alone. It's bolted to 1/8 steel plate, then used the plate for mounting.

I might break down and do a build with the craftsman. It was free, but I'd hate to do a lot of custom work around a cheesy motor.

Oh yeah, I was curious why chainsaw and some other 2-stroke motors are rated such high horsepower for their displacement. Like this Harbor Freight concrete saw. 4.7 hp @ 61cc sounds like a lot to me.
 

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deacon

minor bike philosopher
Jan 15, 2008
8,114
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north carolina
It might be the compression of the chainsaw... My 42cc chainway was a real great motor. The problem was that the drive shaft broke off. That was probably my fault. I had a bad habit of using really big tread tires on friction drive. DON'T DO IT
 

a_dam

New Member
Feb 21, 2009
351
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Momence, IL
Adding to this old thread because I just had another experience with these weedwackers.

My dad has bad feet and legs, so I was doing the trimming in his yard the other day. He has a Craftsman wacker almost identical to the one my bro-in-law gave me.
I started using my dad's trimmer and it sounded kinda rattly/knocky. Sure enough, it had a loose cylinder. Must be a common problem with this model. (weedwacker - 17", 25cc, model 358.795****)

So I knew right away what needed to be done since I did it on the other one. The funny thing is, the jug was loose even though both screws were "locked" with loctite. I had to break them loose, then remove them, apply loctite and torque them down.

So anyone with this model should keep an eye out for loose cylinder screws. Having the jug rattle around can't be doing the unit any good.
 

shadowsaidhe

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Apr 15, 2010
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maine
I don't know if anyone ever answered your question. But a 2 stroke fires once every 2 strokes 4 strokes fire once every 4 strokes. A two stroke will go almost twice as fast for the same cc, w/ more power through the mid and high end. Where a 4 stroke has more torque through the whole powerband. which is why in moto racing 450cc 4 strokes are aloud in the 250cc class.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
I don't know if anyone ever answered your question. But a 2 stroke fires once every 2 strokes 4 strokes fire once every 4 strokes. A two stroke will go almost twice as fast for the same cc, w/ more power through the mid and high end. Where a 4 stroke has more torque through the whole powerband. which is why in moto racing 450cc 4 strokes are aloud in the 250cc class.

Not to argue, but that is only partly true, especially the part about "A two stroke will go twice as fast for the same cc".

Also, two strokes can easily out torque a four stroke of the same capacity when set up right.

The reason 4 strokes are allowed 450 vs. 250 is a weight issue as much as anything, and to encourage the use of 4 stroke's in racing.
 

a_dam

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Feb 21, 2009
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Momence, IL
I don't know if anyone ever answered your question. But a 2 stroke fires once every 2 strokes 4 strokes fire once every 4 strokes.
As far as I can see, nobody asked that question in this thread.

I had asked earlier why some small engines have such a high horsepower rating, but don't remember a 2-stroke vs 4-stroke question.

Actually, the point of the thread is to watch out with these craftsman wacker motors. I'd bet that a lot of people own them (probably not many used for MBs, though).