Halvard Enns

Replace it and it will feel like a different machine again.

Known thing, no damage, and you have already identified the cause. Tipping a four stroke on the wrong side lets oil run into the cylinder or the air filter, and the engine burns it off on restart. A minute of blue smoke is exactly the expected amount.

Next time, tip it with the air filter and carburettor side upwards. If you cannot remember which side that is, tip it backwards with the handle down, which is safe on almost every walk behind mower.

Two things to check now:

• Look at the air filter. If it is oil soaked it needs replacing, or washing and lightly re-oiling if it is foam. A soaked filter chokes the engine and makes it run rich for the rest of the season.
• Check the oil level. Some of it went somewhere.

Wait for the full cure time on the tube, not the touch dry time. Those are different numbers and people read the first one.

One thing that is not normal: howl plus noticeably weak braking. If the power is there you are almost certainly fine.

Check the shower screen seal at the bottom too. Water tracks along the bath rim and over the edge and you never see it happen.

Replace the chain at 0.5 on 11 speed and you will usually get three or four chains out of one cassette. Waiting for 0.75 costs you a cassette every time, which is much worse value than the chain you were trying to save.

Good addition. After a winter sit I would still bet on the jet, but that test takes twenty seconds and rules it out.

Run the bowl dry specifically, not just the tank. The bowl is where the residue forms.

Eight percent is on the high side for some soy waxes and excess oil pooling near the wick makes the cavity worse. Run one batch at 6 percent and see whether the surface behaves before you blame technique.

Running only on partial choke means it is running lean, which means the main jet is partially blocked. Choking restricts air, which richens the mixture, which compensates. Your engine is telling you what is wrong, and after a winter with fuel in the bowl it is nearly always the same thing.

Order of operations:

1. Drain the float bowl first. There is usually a bolt underneath, and on many engines that bolt is also the main jet. Catch what comes out and look at it - varnish, water and green crust are all common.
2. Take the bowl off and clean it properly with carb cleaner, not a rag.
3. Remove the main jet and hold it up to a light. You should see a clean round hole. Anything visible in there is your problem. Clean it with carb cleaner and a single strand of copper wire pulled out of some stranded electrical cable. Never a drill bit, never a sewing needle - scratch the orifice and you have permanently changed the fuelling and you are buying a carburettor.
4. Blow out the emulsion tube and every passage you can see.
5. While the bowl is off, check the float is not stuck and has no fuel inside it.

Nine times out of ten that is the whole repair, it takes 45 minutes, and it costs a can of cleaner. If it still leans out afterwards, check the fuel cap vent - a blocked vent creates a vacuum in the tank and starves it on roughly the timescale you describe. Loosen the cap and run it as a test.

Since it sat over winter, make sure you clean the tank too, or you will just re-varnish the jet you cleaned.

It is the most common way people turn a 45 minute clean into a new carburettor. Copper is softer than brass, so it cleans without cutting.

Note when it reopens. Always late autumn or always in a dry spell is humidity moving timber, and that is benign. Reopening at random or widening each time is a different conversation.

I have been trimming to about a centimetre. Dropping to 5mm on the next test set.

Photograph the linkage and which hole the spring sits in before you touch anything, just in case.

Pilot circuit versus main jet, decided by load, is a clean diagnostic. Straight into my notes.

Or hold the bike still, stand on one pedal and rock it. If it creaks while stationary it is not the drivetrain.

If it will not even cough on starter fluid with confirmed spark, stop looking at fuel delivery. That is the split point in the diagnosis.

A two stroke with good spark and fuel put directly into the cylinder that still does nothing is usually one of:

• Low compression from a scored piston or worn rings. Under about 90 psi they generally will not run properly; under 60 they will not fire at all. A gauge is about $25 and it is the only way to know rather than guess.
• Timing. A fat spark on the bench does not prove the timing is right if the flywheel key has sheared, and a sheared key puts the spark in the wrong place entirely. Pull the flywheel and look - five minute check, very cheap part.
• A spark that looks good in air but collapses under compression. Test with a known good plug gapped correctly.

The sheared key is my first guess on a six year old machine, especially if it has ever hit something solid.

There is your answer, probably. That impact is exactly what shears a flywheel key.

First cassette on the bike, and I changed the chain once before at about 0.6.

Coconut soy takes fragrance better in my experience - noticeably stronger cold throw at the same load, and cure time felt a day or two shorter.

Buy a 25cm knife rather than the 10cm one in the kit. Wide knife, thin coats, and most of the skill problem goes away.

Whole carburettor, and it is not close at that price gap.

A $12 kit gives you a float needle and gaskets. It does not give you a new throttle shaft, and on a twelve year old mower the throttle shaft bushing is usually worn. A worn shaft leaks air, which gives a lean surge that you will then chase for a second evening after a perfectly good rebuild.

For $16 more you get all the wear parts, and you can keep the old one as a backup and clean it at your leisure. Do check that the replacement matches on mounting spacing, bowl style and linkage holes - photograph yours from three angles before ordering.

The kit makes sense on an engine where the carburettor costs $150 and the shaft is still tight. Not on this one.