MTD SNOWFLITE 3/21 Snow Thrower -- A Roadside Find

It's a two-stroke^[1], single stage machine -- a borderline toy, really. Model Number is 319-180A514. Serial Number is 0857276. When I went looking on MTD's web site for a user's manual, nothing came up, so I'm on my own here.

The compression feels reasonable, and the auger looks like it's hardly worn at all. Maybe I've got a useable machine here -- or not. I'll see if it has spark before I commit any fuel to its tank.

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Ten screws fasten the black top cover in place. When you get the top cover off, it becomes obvious that spark plug access is via a capped hole in the dashboard.

The spark plug is a Champion RCJ8Y, with a 3/4" hex. It looks to be in reasonably good condition.

Gap is 0.030". Let's see if it sparks.

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Yes, it does! We may have a working engine here.

The only problem so far is that the kill switch doesn't work. The switch has come apart, and I'm not proceeding without there being a working kill function. So, I'll drill out the rivet that holds the kill switch in place and get that corrected.

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WTF!?

I pulled the starter cord for another spark test and the engine jammed. A bit of fiddling to turn the flywheel in its reverse direction turned up this clip, magnetically stuck to the flywheel.

That was causing the engine to jam up solidly. 'Glad I found that.

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Kill Switch Repaired

Here's a view of the kill switch fixed so it can't come apart.

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No Start

Not so much as a burp.

I dismantled the carburetor^[2], and cleaned out the muck that was residing in it. 'Put it all back together and still no go.

Start

A hint -- don't skimp on fuel^[3] when you're trying out an engine. Fill the tank. Once I got enough fuel in the tank, the engine started. It's too late in the day for me to give it a proper run; the engine is LOUD. Tomorrow I can pursue it.

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Drivetrain

Four screws fasten the drivetrain cover in place. Here's what we have with the cover removed.

That V-belt has seen better days, and must be replaced.

A bail-operated tension-idler serves to engage auger drive. In the disengaged position, a brake shoe presses on the outer face of the V-belt.

There's a part number on the outer face of the belt that appears to be "MTD 754-0101 AD3D". The belt measures 35" in length, so I may be able to get away with using a stock 1/2" V-belt from Canadian Tire, instead of having to go some distance to the small engines shop in Pickering for an OEM replacement.

The tension idler pulley feels a bit lubricant-starved. I'll take it off and give it an oil soaking.

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Tension Idler Pulley Peculiarity

The idler pulley can't be removed from its bracket. The 9/16" A/F hex nut just turns on its stud to no effect. I took the whole bracket off and oiled the pulley's bearing as best I could.

A New V-belt

I got a new 35" V-belt from Canadian Tire.

The new belt has the same cross-section as does the original, so it should serve. Interestingly, though, on the back of the new belt's sleeve the belt is characterized as "fractional horsepower".

This is not a fractional horsepower application; it's a three horsepower application. We'll see how the belt holds up; it has a tough, demanding job to do.

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The Correct V-Belt -- TUESDAY, JANUARY 8, 2019

I got through one minor snowfall with the fractional horsepower V-belt with no trouble, but I thought it wise to get the correct belt. Here's a view of the sleeve from the new belt.

I imagine it's a Kevlar belt. So there's an end to V-belt worry.

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Tension Idler Trouble

The engagement bail's cable terminates in an extension spring that hooks into a hole in the tension idler bracket. The spring's hook-end exhibited a tendency to jump out of its hole, rendering the engagement bail inoperative.

I installed a 10-24 screw with a nyloc nut on it to trap the spring's hook-end in its hole.

Status So Far

The machine is now more-or-less serviceable, but it's hard-starting and rough-running. I've taken it out to the carport with its covers left off it. I'll keep trying to find a satisfactory cold-starting protocol -- the engine must start readily in cold weather for the snow thrower to be of any use. We'll see how it goes as winter proceeds to come on.

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Update --  FRIDAY, NOVEMBER 9, 2018

I tried starting it at a temperature of 5°C, and it started on the second pull. So it appears that I may have a useable toy snow thrower this winter.

I suspect that my earlier hard starting trouble was due to my flooding the engine at relatively warm temperatures. (Above 10°C.) That primer bulb really does its job, and is meant for use in COLD starting conditions.The engine is easily flooded by overuse of the primer.

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Kill Switch Trouble Again

The kill switch is being flaky -- pull the key to kill the engine, and the engine runs on for a bit before stopping. Engine kill ought to be instantaneous when the key is pulled.

I took the kill switch out and examined it. It appears that the switch's steel frame that the spring contact is supposed to short to is oxide-coated -- not rusted, just oxide coated. I scraped the contact surface portion of the switch's frame down to clean, bright steel, reinstalled the switch and hosed it down with WD-40. That should be the end of that malfunction.

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And Still Kill Switch Trouble -- WEDNESDAY, NOVEMBER 21, 2018

The kill switch is still not reliable. I pull the kill key and the engine keeps running. I reach in behind the dashboard and wiggle the switch's wire, and the engine finally dies.

I took the switch out of the dashboard again and gave it a real close look. The crimp connection right at the switch is questionable.

It has sufficient intact strands that it ought to be ok, but the connection looks badly oxidized. I'll try opening up the crimp, scraping it clean and re-crimping and soldering in a length of wire that I can butt splice to the kill wire.

Here's my repair attempt.

We'll see if that solves the problem.

I reinstalled the switch using a 10-32 screw and nut and two internal tooth lockwashers, instead of a 3/16" hollow rivet.

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Update -- WEDNESDAY, FEBRUARY 27, 2019

My last kill switch repair did the job; the kill function is now reliable.

I've referred to this machine as a 'toy', and I was wrong to do that. As of this date, the snowthrower has had some real workouts, and I'm impressed. The amount of work the machine has done for me is amazing. I would never again be without a snowthrower

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Notes:

[1] Engine is Tecumseh-Lauson Type No. AH600-1640N 8153

[2] The carburetor is a very simple float-bowl type. I could find no type number on it, aside from an embossed "46" on its frame.

[3] Gasoline to oil ratio is 32:1. Regular gasoline. For a litre of fuel (about a tankful) add 31.25 ml of two-stroke engine oil to one litre of gasoline. (31.25 ml = 2 tablespoons + 1/4 teaspoon.)

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