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. 

Underdog - the extra lube is a waste. A 2 stroke ALWAYS gets fresh, cool, clean lubrication - it never gets old or dirty, and there is much less to lubricate in the first place (rings and crank bearings are it, basically). In my kart racing series, we run 125cc (the r*tek is 141cc) motors that make 35+ hp and go 50 hours before they need a new top end. This is at 14,000 RPM. We run them at about 50:1. All you're doing with that extra oil is making more smoke and adding extra carbon buildup in your exhaust ports. The motors are stout - just don't over-rev them (same with anything, 4 stroke or 2 stroke) That snow commander is indeed surging, and I know that because it is mine. The pilot jet (behind the sticker) had not been properly cleaned, and that surging is the result. It is also revving too high, as I had not adjusted the governor as of that point (we bought it from a gentleman who stored it outside - it was filthy and full of dirt/crud) I noticed you are a big fan of the HS621 - an excellent single stage snowblower. I haven't run one (only the HS520 - which is terrible), but a Toro 221 or 421 looks comparable (or even slightly better) based on my use of them and in comparison to that video. The snow commander, in my opinion, suffers from a bit of overcomplexity, weight, and one more paddle than is necessary (2 work fine as seen on an HS621 or a 221/421). Although the snow in that video was extremely wet and sloppy (you can see it balling up as I come up the driveway), the 221 threw it much further and didnt bog down (albeit most of the bogging in the video was a product of the too-lean running conditions caused by the plugged up pilot jet) The Commander is also pretty heavy, negating half of the advantage of a single stage in the first place.

Personally, I prefer to mix my fuel at manufacturer's recommendation or richer.  As Underdog mentioned, the engine internals have only one source of lubrication and that's what's carried in the fuel.  For some reason, people like to run oil to fuel ratios thinner than manufacturer's recommendations.  I on the other hand, prefer to do the opposite and run my oil a bit richer.  Once must be careful doing this as well.  Too much oil will displace fuel in the fuel/air mix causing a bit of a lean condition.   I know that sounds strange but it's true.   Being that I have a plethora of two stroke OPE with oil to fuel ratios varying from 25:1 to 50:1, I usually run a quality two stroke oil mixed somewhere in between around 35:1.   I use CTC brand two stroke oil (made by Imperial Oil).  I've been using it for years and all I can say is that it's great oil for the money.    

I hear what you're saying Borat, and understand the reservation, but with a good oil they can, will, and actually DO run better with a leaner mixture (as you mentioned, more oil means less gas, which means a rich mixture makes it run lean and vice versa). The added carbon buildup can cause alot of hassles and in addition, not all of the extra oil will be burnt, resulting in more goo/mess. I've been using Opti-2 at about 80:1-100:1 with no problems for 3 years now in EVERYTHING (trimmer, blower, snowblowers, lawn boys, even my RC Boat)

superbuick wrote:
Yeah, lots of people like to run a lean oil to fuel mix   I mix 100:1 for my newer liquid cooled outboards but like to keep the oil ratio a bit higher in my air cooled engines.   I've been doing that forever.  The Dead Sea was  just getting sick when I started.  

I run a bit of Seafoam through them occasionally and I've been pretty lucky regarding carbon build up.  I'd venture to say that newer two cycle engines would be more tolerant to a thinner oil mix particularly with the better quality of newer oil formulas and synthetics.  However, I'd stay on the rich side for anything that's ten to twenty years old or older.   I guess it's whatever an individual's  comfort level is.   For me, having the convenience of one fuel mix with a slightly higher oil content gives me confidence that the engine's lubrication needs are being met.  

The idea oil packaged in single use quantities is sure appealing. From the advertising it is difficult to know what ratio the pre-mixed product are..

I agree on alot of what you guys are saying about oils.....  All 2 stokes require the same lube requirements,  oil are of diffrent quality...

       Opti oil 2 (I remember the original)...  100:1 mix Is a GREAT oil...  The problem is sloppy mixing of fuel...  If you have a guy working for you that does not check the ratio of the oil to gas as he mixes it, ( mixing too little oil or too  much fuel).. you may have mixed fuel that falls short of the 2 stoke engine's needs..  at about 1.7 oz per gallon,  a small error gan make a the fuel mix around 140:1... 

When Opti oil was big news 20 years ago,  I went to a few oil  shows and asked some questions ...  Most oil suppliers told me they could / have made their oils 100:1 or even 200:1 (some using Murcury metal) , but the consumer will not follow directions closely enough to protect the equipment, and packaging for one gallon mix containers is wasteful...  Hence, a 40:1 or 50:1 ratio is widly accepted as OPE norm and hard to screw up for the end consumer.

-Friiy

 

The R-tek is reading 4138 on the tachometer.  I took several reading and they ranged from a high of 4138 down to 4128 rpm.  I measure the rpms on the shaft that comes out this side of the engine and drives the pulley  

At those kind of engine speeds, with proper lubrication, that engine should last forever.  I've got 35 year old, vintage, two stroke Yamaha twin cylinder motorcycles that have the rev limiter set at 10,000 rpm.  They can spin up to that speed without hesitation and being as old as they are, that should be a testament to their durability. 

The small individual oil bottles might be appealing but you might want to compare the price of their contents to that of a quart or a gallon of high quality two stroke oil.  For your application, having one two cycle machine, it might be worth while using the small bottles.  However, a small plastic measuring cup or calibrated turkey baster will readily measure your oil requirements.  Many two stroke oil bottles have a mixing scale printed on the rear label.  It's handy if the quantities they have printed match your mixing needs.  Otherwise, you'll still have to do some converting.  For those with multiple mix requirements, a custom made chart would be handy. 

Now that you have your carburetor sorted out, I recommend you pull the muffler off for an inspection and cleaning if necessary.  Some two strokes have a fine spark arrester screen in them that tend to clog up over time.  It's unlikely that there would be a need for one on a snow thrower but you might want to take a look nonetheless.   I know you had your machine running nicely already so, the exhaust is probably fine.  After a period of storage, you never know what what take up residence in a muffler.  

Several years ago I had left my old Suzuki ATV at camp unused for several weeks.  When I went to fire it up, it was reluctant to start.  Very unusual for this machine.  After a  minute or so of intermittent cranking at full choke and full throttle, the machine began to occasionally pop.  I cranked it over for a good ten seconds straight with it popping with regularity.  Suddenly there was this big "kaboom" and the engine started.   When the blast occurred, I saw something flying out of the back of the machine, out the garage door and onto the ground.  It was a mouse nest with three half grown mice rudely scattered about in the driveway!  

I'm assuming that the explosion was caused by raw gasoline accumulating in the header pipe and being ignited by flames from one of the engine pops.  Either way, it certainly cleared the exhaust system.    

I will check the muffler. Its easy enough to do. In fact everything seems easier to do with this motor. I'm still withholding judgement until the snow comes. But it is reassuring to hear of the longevity of some of these motors.

Is a measurement of RPMs at the output shaft representative of the engine rpms? Is there gear reduction that would create a difference between the two (engine/shaft) as there is on the Yamaha 4-stroke snowblower?

The output shaft from the engine should be the end of the crank shaft.  Accordingly, that's a good place to measure the engine rpm.  I usually use an electronic tach .   With those, you just wrap a wire around the spark plug lead and it reads engine speed.   Don't know anything about gear reducers on the four stroke Yamahas.  Never been exposed to one.