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. 

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.

Here's a trick for cleaning the carbon out of a muffler:

Remove the muffler, place it on a hot charcoal (or even gas stove) and heat it to the highest possible setting for about 15 minutes.  Any carbon inside will turn basically to dust and you can simply tap the muffler lightly and watch it fall out.  Works great on old Lawn Boys which used to run at 16:1 and 32:1 back when oil quality was mediocre at best.

The motor will have more than enough grunt for just about any snow conditions.  I have one on my 2 stage PowerMax 726te and it will chew through nasty nasty snow that bogs down even much bigger 4 strokes.

superbuick wrote:
Will the high heat burn off the galvanized coating on the muffler and cause it to rust out?  Or is 15 minutes not enough time to do that kind of damage.  My charcoal grill can reach 500 degrees F without much trouble.

The exhaust gases passing through the muffler can attain some very high temperatures.  Chances are that the coating will not be effected.  Another way to clean the exhaust is to put an ounce or so of diesel fuel into the muffler,  shake it around, ignite it with a butane torch and keep the flame blowing through it until it's burned out.  Either process will get the job done.

It's probably unlikely that the exhaust will need to be cleaned.  If you don't see an accumulation of carbon right around the exhaust port or see carbon accumulations inside, it's probably not in need of cleaning. 

Hasn't burnt off the coating on any of  mine, but Borat is spot on - its unlikely it needs cleaning.  If it does, though, either of those methods work well (on 2 or 4 stroke engines).

It's been a year now, how's it running?  I recently got a very similar unit (CCR 2450 - 38413) with the R Tek 5hp for free but the thing won't stay running.  After the first time you start it, it will run under a load for several minutes and then die (can't do anything to save it like primer or choke).  On subsequent startups it will die very quickly.

This is why I got it for free.  The guy I bought it from said it worked perfectly but was leaking gas before he brought it in for service at Acme tool.  Acme found the recall with the cracked gas tank and replaced.  When my friend received it, it wouldn't run.  Then Acme rebuilt the carb and it still wouldn't work.  The tech at Acme said that it was due to low compression ~100 psi and it should be 130.  Now it's in my lap.

I've pulled the carb apart and looked for anything outside of the ordinary, cleaned it and put it back together.  I noticed remains of a sticker around the pilot-jet but finished cleaning the carb and replaced.  It ran exactly the same, no joy.

Recaling the tape remains around the pilot jet, I put a piece of tape over the pilot jet..  It worked perfectly, for about 10-15min (much longer this time) and then died again.  Now it's possible the tape came off??  What did you do with yours?  Did you have to tape over that pilot jet?  In this discussion forum thread I've seen someone suggest that you don't have to cover the pilot jet but I've also seen in the R tek service manual that it's one of the differences between the R Tek engine and the DuraForce engine.  What did you do?

Pull the head off and see if the piston is dished out on top or burnt. Also can run the piston down and check some of the cylinder for real deep scratches. Or take the exhaust off and take a look see in the port that the rings arent scraped over