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

Does these two models share the same chassis and paddle set?  The Rtek engine is the same, however, the 3650 is rated at higher HP.  Is there a REAL difference in HP?  Apparently this same engine is used in the Toro Snow Commander rated at 7 HP.  What gives?  Why 3 different HP rating for same engine?

On a related topic, how does one go about raising the HP of these 2 stroke engines?  Remove the governor and add throttle control?  How do you do that?

The jetting on all of the snowblower r*teks I have worked on is the exact same. 47.5 pilot jet (Lawn Boys have a 37.5 which often causes a surge so alot of lawn boy guys replace them with suzuki or r*tek pilot jets), same needle/seat assembly, and same main jet (I forget the number). I don't necessarily believe that they run at a higher RPM, and if they did, simply bending your governor tab would change that. They all sound exactly the same. Also, Toro switched to the "less bolts" paddle design in recent years, so I have to assume it is an improvement - the older models had bolts the full width. The rubber is thick and fiber-reinforced like a tire, so I wouldn't worry about that much at all. Plus, if something is going to break, the auger is alot cheaper than the gearbox or crankshaft.

Changing jetting will also require air intake and exhaust efficiency improvements to gain any potential the jetting may offer. I'm certain that there would be considerable differences in engine parts if there were any real differences in power. If the machine is up to the task, adjusting the governor spring tab would be an easy route to gaining more power. I know that most two stroke engines running at 3600 rpm can handle an rpm increase with virtually no additional stress. I've got a twenty year Echo lawn mower with at 140 cc engine. I had it spinning at 6500 rpm making somewhere around 12 h.p. The engine didn't seem to mind at all. I've since set it at 4000 rpm max. which is 1200 more than factory setting. It also has a controllable throttle so I can set the speed if I want to run it slower. It cuts heavy wet grass much better at the higher rpms. If anyone is planning on adjusting their governor, they should use a tach of some sort to give them a reading of what the engine is running at wide open throttle. Mini Tachs can be had for around $25.00 USD. They're very simple to install and use. Does anyone know what rpm these R-tek engines run at in stock form?

superbuick wrote:
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.  Interesting is that 3650 is rated for 6.5 hp, Snow Commander is for 7.0 hp while both run at same RPM.  Hmm...  I guess Toro believe that you should get more on paper when you pay more.

borat wrote:
12 hp walk behind lawn mower! That is quite a hoot.  Wonder what it does to mulching.

I think I'm interested in bumping up the RPM on a two stroke engine.  Where can I find those mini tachometer? 

Yeah, the problem with all of that additional power was the additional speed. It's self propelled. That was the main reason I sped up the engine was to gain more walking speed. It was just too slow running at 2800 rpm. Now, with it set at 3600 to 4000, it's a good clip without being too fast. Here's a link to one brand of tach. Shop around, I think I've seen them close to half that price. What's really annoying with these things is that you cannot change the battery in them. They're sealed. They're supposed to last five years or so, but that doesn't impress me. Not for $40.00. http://www.jackssmallengines.com/hour_meter.cfm

I'm not impressed with the price.  These mini tach should be around $10-$20, not $40 and $60 at some places.  There's not much to them, even with a sealed battery.

Snow Commanders use a different cylinder and piston than regular R*tek's. The Cylinder has two boost ports flanking the intake port, and the piston has matching windows for those boost ports, that's the main difference and allows a greater air/fuel charge into the combustion chamber = more horsepower.

Loblolly77 wrote:

Like he said
 

So it does, in theory.  Any real gain in HP?

Anyone check the part numbers from Toro/Briggs?  I have 2 "7hp" r*teks and 2 "6.5hp" r*teks in my garage at this very moment and I can tell no difference between them in starting/running/rpms/power.  they are all extremely powerful, easy to start, and run at almost identical RPMs.  The carbs all have the same jetting too (though one of the 6.5hp motors has a metal carb - all the rest are plastic carbs)