Miele S2 Momentum Vacuum Cleaner Service Note

The Miele S2 Momentum is a fine piece of high-tech machinery; that is to say that it's largely unrepairable by conventional means in a home workshop. If the machine's electronics or motor develop a problem, you'll be out of luck -- you'll have to take it to a shop that's equipped to deal with the machine's architecture. However, it's still worthwhile to check out a dead machine's fundamentals -- even sophisticated machines are prone to simple failures.

Our unit died on us recently, and the trouble turned out to be an open circuit condition due to a line cord plug defect. Here's a view of what I discovered within the line cord plug.

The plug's neutral tine had fractured within the plug's encapsulation. When I cut and filed away the plug's encapsulation, the neutral tine came away with just a nudge. A conventional, screw-terminal Leviton plug from Canadian Tire made for a neat repair, like so.

The machine is back in business at very little cost. A factory-authorized repair outlet would no doubt have insisted on replacing the entire cord reel assembly to effect a repair -- easily a $100.00 repair job, more than likely.

I had to open up the machine in order to do a continuity test on the line cord. The casing has some concealed claws that make access a bit of a challenge, but once you know about them, it's not too difficult to get the machine opened up. Proceed as follows to open up the machine.

Filter Bag and Filters

Remove the filter bag.

Remove the exhaust filter. (The rectangular filter up on top.)

The remaining rectangular filter in the rear wall of the filter bag compartment can stay in place. (It's the motor pre-filter.)

Lid Removal

Spread the lid at its hinged pivot-points to free the lid from its hinge pins.

Upper Shell Fasteners

There are seven obvious screws to be removed. You'll need a T20 Torx driver. The screws are all the same length.

Foot Switch Cap

This is the tricky part. It's pretty much impossible to show by way of a photograph how this item is fastened. There are four concealed claws at the rear that must be unlatched -- two that keep the foot pedals from flipping up, and two that retain the entire cap.

Start by forcefully raising the front of the foot switch cap with your thumbs. It will snap free upward, getting you to here.

Note that the cap is now tipped up at the front by about one inch from its normal, seated position.

Near the centre-rear of the two 'pedals', there are two claws that keep the pedals down in place. Trip those two claws with a small screwdriver, and you'll get to here.

Now, looking down into the rear of the machine, you'll be able to see the two claws that are holding the rear edge of the cap in place. Trip those claws with a screwdriver, and you'll be able to free the cap completely. Here's what you'll see.

Unlatch the white cover, and you can tip it up to your right, like so.

Free the cable, circuit board and switch from the white cover.

Free the white cover from its hinge pins.

Upper Shell

Down inside a deep well, you'll see one last screw to be removed. With that screw out, pry up the upper shell at the front of the handle to free the front edge of the upper shell. There's also one claw-tower near the rear of the filter bag compartment. Trip that claw, tug the shell forcefully upward and it'll come away. You'll now have full access to the machine's innards, like so.

For the trouble I was having, opening up the machine like this allowed me to do a continuity test on the line cord and its reel. That led me to an unambiguous diagnosis of the problem.

Note the following:

a) The on/off switch is not the power switch for the motor -- it's merely a signalling switch that triggers a solid-state switch.

b) The solid-state motor current switch is embedded in the motor -- it's not a discrete component that's accessible for test or replacement.

c) The circuit board is for motor speed control and, presumably, over-heat detection/shut-off.

Re-assembly Note:

There's a peculiar-looking white flexible shaft associated with the motor speed control knob in the foot switch cap. When reinstalling the foot switch cap, you'll have to take care to guide that shaft so it mates with a potentiometer on the circuit board. Aside from that little detail, re-assembly is reasonably straightforward.

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Ryobi RY09466 Leaf Blower -- Engine Teardown

See this post for the externalities tear down to get the engine out of the machine.

Here's a view of the engine.

I'm only tearing down this engine for amusement. No internal parts are available for it -- an overhaul is not on. I'm just curious about how it looks inside; it has almost no compression, and won't sustain operation at wide open throttle.

So, here goes a step-by-step tear down, for what it's worth.

1) Drain The Oil

2) Air Cleaner Body

- Crankcase ventilation tube off of nipple at top of air cleaner body.

- Primer suction tube off of nipple at right side of carburetor.

- Two M5 prevailing torque hex nuts (8mm A/F).

3) Carburetor & Gasket

They're free to just come off.

4) Breather Check Valves & Tubing

Note the directionality of the two check valves. Each valve's conical end points in the direction of flow.

5) Carburetor Heat Dam, Baffle & Gasket

Two M5x22mm washerhead screws (T25 Torx recess).

The screws were installed with threadlocker, and will take some effort to remove.

The gasket will likely be firmly stuck to the cylinder head.

6) Muffler & Gasket/Heat-Shield

Three M5x38mm truss head screws w/split lockwashers (T25 Torx recess).

7) Spark Plug

It's a Champion RY4C -- 5/8" A/F; 0.025" gap.

8) Ignition Module

I don't have a gap figure for it. It measures about 0.008".

9) Flywheel

A 3", two-jaw puller gets it off nicely.

10) Valve Train Cover & Gasket

One M4x27mm washerhead screw (T20 Torx recess).

11) Crankcase Cover

Nine M4x12mm cap screws (T20 Torx recess).

- - -

And here we have an engine that's well and truly done like dinner.

It's impossible to photograph well, but the cylinder wall scoring is horrific -- you can feel the ridges.

This engine must have been run out of oil. It's a wonder it was still able to run at all.

Conclusion

These little engines demand reasonably conscientious attention. A 65ml sump capacity leaves very little margin for neglect.

This particular engine came to an unfortunate end, but that's no reflection on the engine's quality of manufacture. These machines are jewels of precision engineering and construction, and ought to be treated accordingly.

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Ryobi RY09466 Leaf Blower Tear Down

I have an old Ryobi RY09466 leaf blower with an utterly worn out engine. It was a $2.00 garage sale find that didn't pan out, so it's pretty much landfill. (See this post for the back story, and some basic maintenance information.)

I've got plenty of time, and little else better to do, so I thought I'd tear the machine right down, and at least get a good look at its cylinder wall, to see what the damage looks like. Overhauling the engine is out of the question -- the parts, if I could even get them, would likely cost me at least as much as a new machine. But if I can learn more about small engine architecture, I'll be happy. So, here goes.

Here's a view of the complete machine as obtained.



Its external choke lever is broken off, and the air cleaner cover and filter element are missing. Judging by its very low compression, the machine has seen long service, and heaven only knows how long it was run without an air filter.

1) The Nozzle



Shown above is the nozzle in its latched position. The latching effect is very secure. I needed a big pair of Channellocks to twist the nozzle out of its latched position. Twist CCW (as viewed nozzle-output-end-on) to unlatch it from its studs, then pull it off.



2) The Right Side Engine Cover

Four No. 8 x 11/16" threading screws, and one M4 special shoulder screw (all T20 Torx recess).

3) Right Side Of Handle

Three No. 10 x 3/4" threading screws (T25 Torx recess). Watch out for a little steel rod part (a ground wire) at the top of the handle -- it will be free to fall out once you take away the right side of the handle.

4) Throttle Cable Disconnection

Throttle cable anchor removed from air cleaner body. (One M4x16mm pan head screw -- T20 Torx recess.) Throttle cable disconnected from throttle crank.

5) Kill Switch Disconnection

Two spade terminals.

6) Bottom Right 'Handle'

Two No. 10 x 1/2" truss head screws (T25 Torx recess).

7) Fuel Tank

[The above photo is in error -- the bottom right 'handle' shouldn't be there.]

Two fuel line connections:

- The front-most line connects to the lower carburetor nipple; that's the fuel supply tube.

- The rear-most line connects to the right side primer bulb nipple; that's the fuel return tube.

Three No. 10 x 3/4" pan head screws (T25 Torx recess).

8) Left Side Cover

Seven No. 10 x 3/4" pan head screws (T25 Torx recess); one latch.

9) Impeller

One 3/8" - 24 nylock hex nut (9/16" A/F). The nut is a right hand thread. Use an impact wrench to free it. NOTE the two oversize flat washers.

10) Impeller Housing W/Starter

Four M4x19mm cap screws in deep wells (T20 Torx recess). NOTE the sleeve and flat washer on the output shaft.

- - -

And there we have the engine free of its externalities.



I'll begin a new post for the engine tear down. This post is getting dangerously lengthy.

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Homelite 3514c Chain Saw -- Top Cover Removal

The top cover of the Homelite 3514c chain saw can be a bit obstinate, and the removal procedure given in the operator's manual is hogwash. Here's how to get the top cover off.

First, remove two No. 10 x 5/8" threading screws (T25 Torx recess). They're in deep wells at the rear corners of the cover.

The remaining hindrance to removal is a difficult-to-see hook & stud at the front left of the cover. Here's the best I can do to illustrate how that's dealt with.

You have to get a screwdriver into the sweet spot between the hook, and the left side of the cover. Twist/pry and the little stud on the cover will snap free of the hook, freeing the cover.

Here's a view of the hook & stud that make top cover removal difficult on this machine.

Getting the cover back on is not so easy, either. It tends to fight you at two places.

a) At the left front corner, in the vicinity of the hook & stud, there'll be an overlap that has to be forcefully overcome.

b) At the rear, by the primer bulb, there's a lip that may need to be coaxed into place.

And there we are. Put the two screws back in, and you're away.

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Poulan 2050 Chain Saw -- Carburetor Diaphragm Replacement

Hard starting, and failure to idle/accelerate, are symptoms of a stiffened carburetor metering diaphragm. Use of ethanol-laced gasoline makes diaphragm stiffening inevitable after a few years of service.

Following is the procedure for diaphragm replacement on a Poulan 2050 chain saw. (The carburetor shown here is a Walbro WT324.)

1) Top Cover Off

Loosen off three captive No. 10 screws (T25 Torx recess) to free the top cover. The cover comes away easily.

Note the pinched spark plug wire. Someone was careless once when reinstalling the top cover, and pinched the wire's insulation quite badly. Fortunately, the wire's conductor is undamaged, and the wire still functions.

2) Air Filter Element Removed

3) Air Filter Housing Removed

Two M5 flange nuts (8mm A/F).

That gets you to where the carburetor is unfastened. Note the following:

- Choke Pull

Don't try to free the blue choke pull from the choke lever plate. Just slip the choke pull's grommet out of its notch. The choke pull can remain attached to the carburetor throughout this job.

- Fuel Lines

There are two to be disconnected.

The upper one is fuel supply from the left side of the fuel tank.

The lower one is primer suction from the rearmost primer bulb nipple.

- Throttle Link

With the fuel lines disconnected, you can manipulate the carburetor so as to disconnect the throttle link.

4) The Carburetor Off The Engine

5) The Pump Side

A single 8-32 x 3/8" pan head screw fastens the pump cover in place.

Note that the diaphragm goes to the body of the carburetor; the gasket goes to the cover.

6) The Metering Side

Four 4-40 x 1/4" pan head screws fasten the metering diaphragm cover in place.

Note that the diaphragm goes to the cover; the gasket goes to the body of the carburetor.

Note also that there's a small extra hole in the cover aside from the screw holes. That hole must be clear of debris, and open to the atmosphere, in order for the metering diaphragm to function.

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Chain Saw Carburetor Contamination

Here's a view of a sawdust-contaminated carburetor off a Poulan 2050 chain saw.

The saw had experienced a fuel line tubing failure, and probably ran for awhile with its fuel filter broken off from its fuel pickup tube.

I guess the lesson is, "Dismantle and flush any carburetor that's been run without a fuel filter."

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Fuel Line Tubing Nipples For Small Engine Fuel Tanks

A common practice among manufacturers of small engines is 'squeeze-through' installation of fuel line tubing. Here's an example of it on a Ryobi leaf blower.

The fuel tank has no nipples. At the factory, the resilient fuel line tubing is squeezed through undersize holes in the wall of the fuel tank to effect a sealed installation.

It's a dirt-cheap method that lasts for at least the warranty period, so the manufacturers love it. Serviceability leaves something to be desired, though.

Fuel line tubing installations all have a finite life; eventually, the tubing gets brittle/rotten and fails. If you can get exact replacement tubing, you can probably re-create the factory's tubing installation. If available tubing is undersize or oversize in the outside diameter dimension, you have a problem.

I've taken to getting around the problem by fabricating nipples from 1/4" - 20 threaded rod, and 1/8" hard brass tubing. Here's a view of such an installation on a Weed Eater string trimmer's fuel tank.

It's a bit of work, and parts of it can be awkward (e.g. fitting the fuel pickup tube inside the tank), but it gives you a fully serviceable fuel line tubing installation that's not fussy about tubing outside diameter.

I have an old Poulan 2050 14" chain saw that's in need of new fuel line tubing. The machine's fuel tank architecture is not friendly to modification, so this will be a bit of a challenge. But it will let me use tubing that I have on hand, saving me a trip to the small engines place. Also, even if I had just the right tubing, it would be very difficult to re-create a squeeze-through tubing installation on the Poulan's fuel tank. It's not a design that lends itself to serviceability.

Before starting in on one of these jobs, make certain to create a photographic and/or written record of your machine's correct tubing connections -- they can be a difficult thing to puzzle out without documented guidance. A typical installation will have the following elements:

a) Fuel pickup tube from fuel filter inside tank, through tank wall, to fuel pump side of carburetor.

b) Primer suction tube from primer bulb to metering side of carburetor.

c) Primer return tube from primer bulb to a hole in the tank wall.

Items 'a)' and 'c)' above are those that need to get nipples provided.

Fuel Tank Preparation

Drill out the tank's tubing squeeze-through holes with a No. 7 drill, and tap the holes 1/4" - 20.

Here's a view of the upper wall of the Poulan's fuel tank with its two squeeze-through holes.

The smaller, upper, left-most hole is for fuel pickup. That will need a double-ended nipple.

The larger, lower, right-most hole is for primer return. A single-ended nipple will suffice there.

And here we are with the two holes drilled out and tapped, and all the chips blown away with compressed air.

The Nipples

Here are two finished nipples.

The 1/4" - 20 threaded rods are 13/32" long; the 1/8" O.D. tubes are 1" long. The threaded rods were bored through on a lathe. The pieces are assembled with CA adhesive. Note the filed wrench flats. (It was just as easy to make both nipples double-ended, even though only one of them needs to be.)

Coat the threads with CA adhesive prior to installation, and be ready to screw them fully in quickly, before the CA adhesive seizes on you. The fuel pickup nipple will have to have its tube in place before the nipple is installed -- it will be very difficult, if not impossible, to get the tubing on the end of the nipple, once the nipple is in the fuel tank.

With the fuel pickup nipple installed, attach the fuel filter from outside the tank, and tuck the works inside the tank.

And here's how the nipple installation looks up top.

Now it's just a matter of reinstalling the carburetor with correct tubing runs. If everything else about the engine is ok, your machine will be back in business. The subject chain saw here primed properly and started up easily with this repair/modification done.

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