Find a clutter free area and workbench, bring in the snow blower. Have your tools ready and cleaning cloths to hand.

1. Drain the engine oil and old fuel into containers ready for recycling.
2. Remove the carburetor and clean it (see previous post). Take off inspection covers and check drive belts for wear.  If the belts show any sign of damage or deterioration, now is the time to replace them. Before removing old belts, photograph them, the position of the tension pulleys and where the tension springs are anchored. Their positions look obvious before dismantling, but when replacing the belts, what was their correct position is not so obvious.
3. If you have a snow blower with a speed selector, tip the snow blower on its front end, with the handles in the air. Take off the base and cover gear covers. The drive is a friction disc that moves across a larger aluminum disc. Check the rubber around the outside of the friction disc for damage and wear and replace if necessary.
4. Whilst the snow blower is in this position, check the wheel bearings, is the drive shaft firm or is there a lot of play due to worn bearings. Because of the way in which the wheels are driven from the speed selector, there is an uneven force on the wheel axle. This does cause wear in the bearings, particularly those with plastic bearings. Broken or worn bearings can be replaced, by removing the wheels and bearing housings.
5. Lubricate moving parts, linkages and grease hex shaft that the friction wheel slides along. Keep grease away from the rubber on the friction disc and the surface of the aluminum disc.
6. Check the tire pressures and if you have chains on those tires, make sure that there are no broken links. Replace covers and set the machine back on the level.
7. Obtain a spare set of shear bolts for the auger. DO NOT USE REGULAR bolts.  I have had many a snow blower in the workshop where regular bolts had been used on the auger shaft, resulting in a broken auger gearbox.  Shear bolts cost just a few dollars but a new gearbox, auger and drive shaft run into hundreds of dollars to fix. Check auger shaft bearings and replace those if necessary.
8. Lubricate worm drive and gear on chute and that it operates freely when turned to deliver the snow to where you direct it.  I found waxing the inside of the chute with car wax, helps to reduce the amount of snow build up and blocking the discharge chute.  When in use and the discharge chute blocks, STOP ENGINE before clearing out the snow. This may seem obvious, but when you are cold and want to get inside for a hot drink, you are not always thinking about the consequences.  Some time ago I did have a customer who lost the tops of his fingers by just doing that, trying to clear snow blockage from the chute.
9. If the snow blower has an electric starter motor check that it is working correctly and engaging with the engine and turning the engine over.

10.  After lubricating and cleaning the snow blower, fill the engine with 5W 30 oil, and put fresh gas in the fuel tank.  Gas companies change   the gas formula for winter driving. The gas is blended so as it will vaporize at a lower temperature.  Summer gas can make it very difficult for the snow blower engine to fire up on a very cold day.

Basic maintenance and by being careful, much of the regular service routine can be done, which in turn will save you money.  I found that by taking a few digital photographs, of the carburetor linkage, the tension pulley set up, the direction and lay of the drive belts, saved time and frustration when reassembling.

Since there are many different makes and models of snow blowers, this article is representative of many snow blowers on the market that I have serviced, but I cannot be held responsible for any injury or incorrect assembly that causes damage to the machine.

A snow blower that runs and performs well saves time, money and frustration. If you need parts for your snow blower check out http://www.discountonlineparts.com/snowblower

Whenever you are in doubt, take your blower to a competent service center or email me.

Float style carburetors are common on small engines used for outdoor power equipment, in particular the lawn and garden tractor. Many times when the engine is running rough or is hunting badly (engine speed not constant) it is because the carburetor needs a good cleaning and service.

Preparation

Record the engine type and serial number and obtain the relevant carburetor kit, engine and filter gaskets. Prepare a clean work area, an area of no smoking or naked flame (gasoline vapors ignite very easily). Basic tools required are set of wrenches (socket or open ended), needle nose pliers, can of carburetor cleaner, a container to clean parts and a container to store parts.

Carburetor Removal

Take a photograph or make a pencil sketch of the choke linkage, governor linkage and springs connected to the carburetor. This will save a great deal of heartache when you come to reassemble. Shut off fuel to carburetor before removing fuel line to carburetor.  Some have a fuel shut off valve, if not clamp the rubber fuel hose with a G clamp.

Remove the air filter, the carburetor fixing nuts (screws) and governor spring.  Ease the carburetor away from the engine, twisting as you do so to disengage the Z shape linkages to the choke and throttle valves. Note that there will be fuel still in the bowl at the base of the carburetor. Tip carburetor upside down to let the fuel drain out into a container.

Carburetor Disassembly

Now that you have the complete carburetor in your hand and before attempting to take apart, look for the two screw (some have only one) with springs under the screw head.  These will be the idle and high speed adjustment screw.  Count the number of turns required to screw home the needle, about 1 & 1 ½  for the main jet and 1 time for the idle jet.  Make a note as this will be setting will be used later.

Remove the high speed and idle adjusting screw, clean and place in a container ready for reassembling. Remove the bowl fixing nut, on some carburetors this nut was where the high speed  adjustment  screw was located.  Clean the nut and replace washer if required.  Those that house the high speed needle will have one or two small fuel transfer holes. These do get clogged – clean out with thin wire. The float  comes next, watch out for the fuel inlet needle and how it is attached to the float hinge.  Some of the brass floats do leak after a time, check by shaking float to hear fuel sloshing about, if so replace.

Use carburetor cleaner and spray outside, then the inside of the carburetor, the air and needle orifices. WATCH YOUR EYES – USE GOGLES. Ensure that the choke and butterfly valves move freely and that the throttle and choke return springs are closing the valves.  If weak or broken then replace by unscrewing the butterfly valve and removing the spindle. Inside the venturi at the throttle valve end there are 2 or 3 small holes (need to move the valve to open position to see them). I use a staple with one leg bent straight and using needle pliers cleaned out those ports.

Reassemble

Insert the needle and float. Using a new ‘O’ ring, fit the bowl to the carburetor. Screw in the high speed and idle needles (don’t forget the tension springs, ‘O’ ring and washer) until they just seat, then back off the screws by the number of turns you recorded when disassembling.  These settings should enable the engine to start – final adjustment will come later.

Using the photos taken or your sketch, insert the governor and choke linkage, then with a new gasket fit the carburetor to the engine body.  Reconnect the governor spring into the hole on the throttle cam, usually the same hole as the governor linkage. Reconnect fuel line and filter cover (with new gasket) to the body of the carburetor. Replace worn or dirty air filters

Adjustment

Start engine and allow it to warm up to normal operating temperature (3-5 minutes).  Set the throttle control to the maximum speed position, then turn the high speed mixture control in (clockwise) slowly until the engine runs erratic. Note that screw position.  Now back off the screw (counter clockwise) until the engine again begins to run erratic. Note that screw position, then screw back in to the mid position at which point the engine should be running smoothly.

Set the throttle control to idle or slow position and adjust the idle mixture screw in the same manner as you did with the high speed mixture control. Some times after setting the idle screw you may need to go back and readjust the high speed setting.

Disclaimer – This article is intended as a guide and is generic and therefore I cannot be held liable for injury or damage. There are many types of carburetors used on small engines, each with their own means of controlling the fuel/air mixture to the engine. However the above is typical of many carburetors used on small engines that I’ve serviced and repaired during the years I owned an outdoor power equipment sales and service business.

The above diagram copyright Tecumseh

Brian Wenham