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

I have an old Ariens snowblower that is in good shape but with a tired engine. I've been looking into a new replacement. The logical candidates seem to be the Tecumseh OHSK70, the B&S Intek 7.5, and the Honda GX200. 

The Honda seems to have the most torque (10 ft lbs) but is also by far the most expensive - $500 versus around $300 for the other two.

I have never seen a torque figure quoted for the Tecumseh, but it seems like the Intek 7.5 is around 7 ft  lbs?

Another engine that I came across was the Robin Subaru EX series, a 7hp OHC engine that has a lot of advanced features but isn't much more than the B&S or Tecumseh. They all have the same crankshaft (3/4") and height (about 4.17").
B&S sent me data sheets on the replacement: the Honda dealer has an employee who did one; and Tecumseh gave me all the dimensions and concerns (mostly about fitting the chute crank under the engine) but they all seem like they'll work.

I live in Boston MA and the current unit is a Tecumseh H50 on a 1970 Ariens. I checked the compression and it's 65 psi on the first pull and 75 psi after 2 or 3 (by hand pull). I do the sidewalks up and down the street for  some older (or lazier) neighbors so the kids can walk to school without walking in the road. The blower is great because it compacts the snow a bit and the biggest problem here after a snowstorm is finding a place to put it. I've used the unit 8 times so far this season.

The new pulley arrived today.  It is installed on the shaft along with a longer belt.  The original engine is shown for a side by side comparison.  Note the increased size of the engine pulley.  I am looking at incorporating a "Dead Man"  belt tensioner as the auger and wheel drives on these old Ariens keep going if you let go of the handle bars while blowing snow.  Thanks for your tips and suggestions.

6HP Tecumseh and 11HP Honda

It looks like the new pulley is at least double the size of the old one. That means the auger and impeller will be going over twice as fast. While this means the snow will be thrown faster and further it also means there is a lot more stress being put on the entire auger/impeller system. You will probably get a great deal of vibration and things will wear out pretty fast. Try using the lowest gear possible for the traction system or you might be running after a snow bazooka. Make sure you're no "aiming" at anything important.

Excellent point Nibbler. Dans the engine pulley on my similar Ariens is 2.5" in diameter matched to a 9" drive pulley that reduces the 3600rpm of the motor to 1000rpm for the impeller. By using only a 2.75" pulley the angular frequency of the impeller increases to 1100rpm, a 10% increase. Match that 10% with your 11HP (wow) and you should achieve very good distance. Please keep us up to date.

According to a previous post the new pulley has an OD of 5" as opposed to the probable 2.5" of the original. That means the auger rakes are running at about double their designed for speed. Add in the extra horsepower and there might be a problem with the auger system being too powerful and fast.

The other thing to note is that the final RPM reduction occurs in the worm gear that converts the front to back axis of rotation into a left to right axis of rotation. I'd be afraid of an auger running at 1000RPM although you wouldn't need an impeller for a second stage boost.

With a 2.5" pulley the impeller runs at 1000rpm, there is a 10:1 ratio for the auger, therefore auger turns at 100rpm. BTW a 3" engine pulley would increase speeds by 20%. probably the max. that can be achieved without too many problems as nibble mentioned above 5" pulley means impeller runs at 2000rpm way too fast. please note that I am no OPE expert.

nice

Dans, how's the engine swap going? I'm curious b/c I'll be doing the same in the spring, in the time being I’m looking on eBay for a good deal on the engine.

Garandman,

Sent you a PM.  Would like to do exactly what you did with your 70's Ariens.