Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Guys,

I may get to go check out some SS's. One is a Yardman 21" 5hp 2-stroke. The other is a Toro CCR2000e 2-stroke.

I am leaning towards the Yardman, based on boratification possibilities. I'm guessing/hoping it has a 5hp Tecumseh, maybe the HSK850. The Toro would have a 4.5hp Suzuki engine, from what I understand. I don't care about electric start. Any reason to avoid the Yardman? I realize it's probably not as solid/durable a machine as the Toro. But if it could be ramped up more in the power department, I could live with that. Thanks for any feedback.

Well, an engine swap is looking impractical. Before trying to take the cover off the Ariens, I looked up a bit of info on the crankshafts.

Thanks to the document trouts2 posted a few days ago (http://th.manualwebsite.com/pdf/engine_and_accessories_2001.pdf - a great resource!), I got some info on the crankshaft in the 850, which is 290614. The 600 has 290676. I can't specifically find interface details on 290676 (seems like it might have been a bit of a special for Ariens?). But the main diameters of the 600 and 850 crankshaft outputs are different. So I can't just swap the pulleys (the pulley styles are different between the two machines, ribbed belt vs V, so I also can't just leave them on the engines).

And the proper pulley half for an 850 engine in the SS522 (03801200) would be $30, and you need two halves. (by contrast, the pulley halves for the 600 engine are only $4 ea!). At $60 for a pulley, which may or may not actually fit the crankshaft geometry on the 850, swapping engines does not make any sense. I could buy a whole SS522 for not too much more.

Unfortunately a swap is not an option, but at least that provides direction- go through the Yardman and get it ready Make an engine mount, etc.

Checked the engine RPM of the 850 last night, it's set at 3900. I tried nudging the governor to speed it up. It's certainly quite a bit louder at 5000. It didn't sound bad, but I didn't feel like bringing it up to 6000 just yet. The engine starts quite readily. As I was running & shutting it down, it would fire up again with not even a half pull. It was 1 or 2 pulls (I forget which) when cold. Got the idler pulley's arm adjusted to try and align the pulleys as best I can, based on your good advice, borat. They were out of alignment as-is (no need to munch the belt).

Any engine that is sped up will make more noise.   I'm not keen or revving an engine when not under load.  I'll do it for brief bursts for testing purposes but that's generally it.  When working, you'll notice the engine doesn't seem as loud and changes it's tone.  Could be due to the load effecting back pressure and/or the snow absorbing some sound.  Either way, when working these HSK/TH engines seem to enjoy the higher rpms.   They certainly make serious power for their size and seem to be as "happy" as any two cycle engine I've owned. 

I'd never thought about it this way before, but in some ways, I'd imagine a governed 2-stroke (not a 4-stroke) could actually be seeing less wear at high RPMs & high load, vs high RPMs & no load. With a load applied, the governor opens the throttle significantly. That adds more gas, but it also brings more oil. So under full throttle, your engine is actually better lubricated than just sitting at that RPM. A fixed-RPM SS is a prime example for this, I suppose, since the RPM should be the same whether just warming up, or actually doing stuff. So, let that be a lesson- be kind to your 2-stroke, keep the paddles fed

In terms of noise, the snow would help absorb some sound. You're also doing stuff (not just focusing on the noise), you're *expecting* it to be doing more, and you're also not crouched by the exhaust (like I was last night ).

I had wanted to do something to make the motor mount more secure. When you'd pull the cord, you'd see the top of the engine move to the left as you hit the compression stroke.

I took some measurements of the area around the engine's unused mounting stud. Drew up what I wanted to make, starting with some 2" x 2"  90 degree extruded aluminum. It's just a simple piece, but milled what I wanted, including a radiused face to match the radius of the frame tube I wanted to mount it to. The radius should help keep it aligned with the tube, and keep it from sliding around as much. I bolted it onto the engine's stud, and used a pair of stainless hose clamps to secure it to the tube. The hose clamps aren't exactly fancy, but I had them around, and they'll be plenty secure for this purpose.

Tried pulling the cord, the engine stays rock-steady now It looks much better vs when it was tilting left/right. Took it outside, primed it, started on the first pull. Now I just need some snow to try it on! I haven't tried to boratify it yet. Might start with simply adjusting the governed RPM higher, before trying to rig up something to allow controlling it.

  Nice fix Red. MTD chose a good place for a support.

Red,

Looks nice and tidy, and instantly effective.  Keep a close eye on that nut, they tend to vibrate loose.  Use some blue thread locker liquid or use Nyloc nuts to take prevent that from happening.
 

Nice job red.  What did you use to machine the radius?  Excellent work.

Don't want to second guess you, but did you confirm your pulley alignment prior to building/installing the new engine mount?  If required, you could easily shim the mounting base to raise it and oval out the hole a bit if you need to lower it. 

Thanks guys. aa335, I had a lockwasher I was going to toss in, but the stud was too short. I was so caught up in whether this was actually going to work that I did not just grab my blue Loctite. I will have to go back and add that, good point. "Fortunately", the stud was rather rusty, so the nut was snug already. It came with built-in, brown, threadlock

borat, I had corrected the pulley alignment prior, and I don't think this really shifted the engine noticeably. But I will have to double-check the pulleys, just to make sure I didn't accidentally cause an issue. The mount was sized so that it basically lined right up with the stud location, so I'm not expecting issues with alignment, but I'll check.

The tube is 1.25" diameter, and there was a 1.25" diameter endmill available, so I just used that. If the tube had been a size for which an endmill wasn't available, I would have had to program that feature on the machine, and made it with a smaller cutter. And I'm definitely just learning how to do this, so it was a lot easier being able to just use a tool that happened to be the right size, vs programming.

Edit: and, trouts2, unfortunately MTD did *not* choose a good place for a support. In looking at the parts lists for this machine, I did not notice a reference to any sort of engine mount where I added this. I'm not even sure whether the engine is "supposed" to have a stud in this location (in other words, as was mentioned previously, I can't be sure that this is the original engine; if it is, there was a stud present, and nothing appeared to actually use it). The impression I got was that the engine is really supposed to be supported only around the crankshaft, and the rest of the engine just hangs in space, free to move around. Which doesn't strike me as a good idea.

RedOctobyr wrote:
Yeah, existing rust works as thread locker too.  :)  Forgot about that.  They work so well, sometimes you snap off the bolt trying remove the nut.