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

what size pulley should iput on 305cc engine there is a 51/2'' pulley on blower .it is a 36' cut blower for a lawn mower but i am modifying to go on atv .its a single stage so i want to get most power i can out of it.any help would be appreciated thanks..

would bigger pulley on bottom make any difference or would i be wasting my time.

A bigger pulley on the bottom (driven pulley) would help some with the engine bogging down problem.  But using a larger "driven" pulley is going to drop the RPM of the shaft.  So the auger
RPM will be dropping as well.  Your throwing distance will suffer.  The Blower width, auger RPM, pulley/sprocket combination and engine size are all engineered to work together. If you drop the HP
that the system was designed to be used with.  There really is nothing you can do to get around the lack of power.  You can always increase the power/HP driving a designed system and improve the
blower performance.  But you can't go the other way and offset a lack of engine power by changing the gearing so to speak. 

Bill H has a 48" blower on his tractor which I know is 12" wider than yours.   But he also has a 20hp engine.  That's twice the size of yours, roughly.  I'm afraid you only real option is to get a larger engine.
A 16hp would probably do it.  And as was suggested reducing the clearance between the throwing portion of the auger and the housing is also important. 
If you want to get the maximum performance out of the blower.

As a single stage blower owner and being extremely jealous of all of you knowledgeable 2 stage owners I read all of these threads with great interest. I was thinking about the issue of impeller and auger housing clearance and thought about the possibility of using something like a roll-on truck bed liner like dupli-color bed armor or something similar. Enough coats would probably help with the auger clearance while protecting the housing at the same time. Good idea or bad?

I wouldn't think that the bed liner material would be a good idea.  Although it would be durable.  You need a smooth surface for the snow to travel over. The smoother and slicker the better.  Most bed liner material is textured. It's designed to produce somewhat of an anti skid surface. 

Just to clarify, it isn't really about auger clearance.  On a single stage tractor type blower.  The clearance issue is limited to the two or so blades in the center of the augers. That actually catch and throw the snow up the chute. The augers to the left and right of the center blades/paddles simply move the snow to the center for discharge.

On a two stage blower.  It's the impeller blade to housing clearance is the important issue. 

thanks for all the info iguess ineed more hp.just wonderin would a 2 stage blower work better or would it be the same as a single stage.

A two stage would work. But you'd have the same sort of problem.  A 10hp engine would not be big enough to run a 36" 2 stage blower.

ralphfr wrote:

Is your auger adjustable? Some large single stage blowers have a means of adjusting the auger clearance. Check your manual if you can't tell by looking, or even the parts manual. It makes a HUGE difference.

JRTREBOR - Makes sense. I had a feeling the texture might be an issue. Initially I thought this was just an impeller issue until I read a post earlier in this thread alluding to auger clearance as an issue. Thanks.

BILL_H - Not an issue for my Toro SS as the housing is plastic and the auger is rubber and wears with use but thanks for the suggestion.

checked my rpm on engine today it is at 3640 rpm.would it be safe to turn it up,iread on here someone had turned up to 4500 with no problem.

Most OPE four stroke engines are designed to run at 3600 rpm.  You could spin it at 4500 but who knows what effects it will have?   I have no reservations spinning up two cycle engines.  Not sure I'd want to be spinning an OPE four stroke engine too high.   Go-cart racers do it all the time but they also rebuild their engines every so often.