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

How do you diagnose a 2-stroke to find out if someone ran straight gas through the engine and wrecked it?

I found a Toro snow commander snow thrower (see photo). I've never used a toro single stage so I thought I would snatch it up. The previous owner said that it did not run. Apparently it ran last year but not very well. Looks like it sat out in the rain most of its life. That's all I have to go on. 

At 24" the blower is wide for a single stage and very heavy (over 100 lbs).  The 7hp engine appears to be the same InTek 2-stroke as the Toro 3650 and 2450.  I noticed that it does have an electric start feature.

Now that the blower is sitting in the garage, I realize how large it is. Think "single stage monster."  A very odd beast,  a mass of red plastic.  Toro only sold these (model 38602) blowers for a few years (2001, 2002, 2003, ?) with a list price of $960 US. There was a Toro recall in 2006 for 2001 and 2002 models. This one is a 2003 model.  I don't think they were very big sellers (expensive, hard to handle, too many parts).

I don't have any experience with 2-strokes so this is a new adventure for me. Is there an easy way to determine if someone ran the engine with regular unmixed gas and ruined the engine? Would I notice anything when pulling the starter cord?  I thought I try to rule that out first if there was an easy way to do so. 

A lot to learn for such a simple looking device. I'll let it soak in.

Its not all back together but I was impatient and put some gas in anyway. It started right up. Lots of fun. Noisy and if you watch closely you can see that its smokes.  Still, it was quite a thrill to see it start. 

http://www.youtube.com/watch?v=DZpSxnqzic4

Nice thrower... what did you end up paying for it?

-Friiy

Good going!

Sounds pretty healthy but if that was idling speed, it's set too high.   A single cylinder two stroke should idle around 1200 rpm or so.  Put a tach on it to see what it's running at then adjust your idle screw to bring the revs down. 

borat wrote:

Idle screw. I did not see that any place.  Is this screw attached to the carb? I will look again. I think I remember seeing a photo of a a governor control in the manual.  If my memory serves me, the idle speed was to be 4,000 rpm.  

What about smoke? Am I within an acceptable limit for smoke or is there such a thing?

Thanks for helping me work on this little motor. The kids all jumped up and down shouting when it started. Very exciting. Then at dinner I was told it was "too loud and  too smelly."    You can't please everyone.  

All two cycle engines smoke.  The newer ones with catalytic converters produce very little.   Older engines produce quite a bit when cold but tend to thin out as they get warmer.   Your engine will probably emit less smoke once it warms up.  Four thousand rpm for idle speed doesn't sound right.  That sounds more like max operating speed.  The idle screw is often a screw that puts force on the throttle linkage to open up the butterfly or slide (depending on carb type).  I suspect your carb has a  butterfly.  If so, see if you can find a screw or spring that sets the butterfly opening while at idle.  Something I just thought of now, is that your engine may not have a controllable throttle.  It may be running at max operating rpm upon start up.  Maybe that's what the manual means by "idle" speed.  

superbuick wrote:

Would I know it if I had a surge issue?  Does it surge under load or when idling?
I'll check out the links. It sounds like 2-stroke motors have a big following especially for lawn boy. 

 

borat wrote:
This from aa335 : " The Toro manual states that it is the same Rtek engine with different engine RPM for different models.  The RPM is changed by bending the tab, as  you had mentioned.  3800 RPM for 2450, 4000 RPM for both 3650 and Snow Commander........."

Idle speed is set via the governor.  There is a metal tab on the carburetor that has a spring on it that leads to the governor.  Bending this tab either increases or decreases the tension on the spring/governor.  When you make the spring tension less, it will idle lower, and when you make the spring tension more, it will idle higher.

As far as the smoke - the mix (%) and type of oil you are running has alot to do with that.  I run opti-2 at 100:1 and have no visible smoke in the units I run that in.  They run perfectly with that mix.  As noted by Borat, even with a smokier oil and a richer mix, as the unit warms up, most of the smoke dissipates.

As to your earlier questions about the 2 stroke vs the 4 stroke, I agree with Borat that the 2 stroke is the superior type for OPE.  They are lighter, simpler, and make way more power.  They also require basically NO maintenance.  Run them out of gas each year and throw a spark plug in there about every 5 years or so and you're golden.  Realize when looking at that R*Tek and how small it is, it makes more power than the GX160 and has way fewer parts.  The theory of operation is very simple - if you go on youtube there are a ton of videos showing how a 2 stroke works: 

http://www.youtube.com/watch?v=LuCUmQ9FxMU (is a good one - shows a reed valve but piston ported is same theory just with a third port instead of a reed)

Think about chainsaws and their use profile.  They need incredible power to do what they have to do, have to be light weight to be usable by a single person for long periods of time, and have to be able to run at many different angles.  Then think of how many 4 stroke chainsaws are made....

Nice video. The combustion makes more sense, but what about the lubrication of bearings and sleeves and all those moving parts? When you open up a 4 stroke you can see how the oil has been splashing all over the place providing protection from wear and dirt.  Can a 2 stroke really protect friction surfaces sufficiently? If a 4-stroke is worked hard in dusty conditions you can shorten the oil change interval, not so with a 2-stroke.  The dirt contaminating friction surfaces might build up resulting in a short engine life. 

Because of a lack of faith I may have added a little extra oil to the oil/gas mix.  I suppose that some of the smoke may be attributable to that discretion (Can you blame me?).   

Superbuick, are you setting your idle at 4000 rpm? \

Does the Toro Snow commander in this video sound like it is doing the "surging" thing that has been spoken of ?
Video link here: http://www.youtube.com/watch?v=F0ZmkFeW28E

I don't know if your Toro has a air filter..  or if it should being a snow unit....

The biggest problems I saw with 2 stokes was dust and debris in the lower end... (other than some fool not using mix)

       In lawn equipment,  poeple would often neglect the air filter on the Toro 2 cycle mowers (Suzuki engines) ...  the ingested grit would wear the govenor shaft and bushings in the case.....Otherwise they are great engines (2 stroke)...

   As far as running an engine on slope or heavy slant...  Most 2 stroke motors (chain saws, trimmers and blowers)  have Vacuum Diaphram carbs that do not have a fuel bowl to flood...  but your unit would and could flood if tipped too far  (float bowl)...  4  stoke engines can also run on slopes depending on the carb set-up and oil lube system, but such features are not cost effective for the units, also the added weight of a 4 stroke is not the greatest on a slope..

-Friiy