Problem with a Garden Blower

[Peter Able]

My 29-year-old Little Wonder Garden Blower/Sucker has stumped me. Any thoughts very welcome.

Working very well - then the next day nothing. It is on its third (ZAMA) carburettor. Just before each carb was swapped out I had to start it by removing the air filter and then pipetting in a tiny bit of petrol into the carb's air flow. That would always produce a few fires - which was enough to get it going.

So I tried that - nothing. I tried a new spark plug - nothing. I checked the magneto coil resistance. About 2kohm. I put a timing neon in the path to the plug. Plenty of neon flashes - but still no ignition. Each of these tests were carried out with the air filter on and with the pipetting of petrol, and with one spark plug then the other. Nothing.

I slipped back the rubber at the end of the HT cable and inspected the spark plug cap and checked out the connection of the cap to the wire. Looked OK. I wiggled the cap - which is a spring with about 2cm of the spring unwound and folded by 90 degrees so it can be driven through the wire - and the conduction was near-perfect and was perfect whenever I stopped wiggling it. I, nevertheless, trimmed back the HT wire by about

1cm and drove the 90 degree spring end into the shortened HT cable. Then, wiggling the spring, had no effect on measured resistance to ground. Perfect. Put it back on the plug (yes, both plugs) - and nothing. Neither carb only or pipette

I didn't want to do the ultimate test - sticking a screwdriver in the plug cap and seeing if I got zapped, but I did risk my Fluke DVM between the cap and the chassis. A decent pull on the starter threw the DVM into a full reset.

What am I missing?

Nothing to do with the above, but when I was using the neon, I found I could get a flash with nothing connected to the far end of the timing neon. I guess that that must have been due to radiation off the open-circuit wire.

I'll have OFCOM after me!

TIA,

PA

[Peter Able]

Now that's an idea - a timing error due a shift in the magneto. I'll check that out. I did replace the magneto from a scrapper about four years ago - and it was a bugger to get at.

Playing devil's advocate, I've tried with the plug(s) removed and grounded and couldn't see a spark at the plug. Even with the blower in the relatively dark garage.

Compression-wise, the feel of the starting rope is quite normal. And two plugs - the original and a new one - have been used in all tests described.

PA

[nothanks]

To fire an engine only needs compression, fuel/air in the right ratio and a spark at the right time. Have you checked the magneto fitting? How's the compression? Have you got another spark plug to try?

[Peter Able]

I've disassembled enough to expose the magneto and flywheel. The magneto is tightly bolted in position - and the magnet embedded in the flywheel grips a screwdriver with a similar force to those in my (three!) lawn mowers.

I hate the idea of being beaten - but I can see what looks like a knock-off of the Little Wonder on eBay for just under £90. If it is, then it might let me fit it with the LW's "Nozzle Fan Head (BL)" (Their words). It looks like a Disney duck's beak which can be rotated through

180 degrees; one position for creating a horizontal blow for the conventional uses. The other position for creating a down blow for clearing out things like gutters.

Anyone seen a similar Nozzle?

[Leaflet image produced with scanner converted from Cold Cathode to LED! ]

PA

[Peter Able]

They range from recent to 29 years. All have CDI Honda motors. All still motor. The blower is CDI, too. I've just ordered what looks like a knock-off the Little Wonder from eBay. I doubt that it'll last 29 years. I'm pretty sure I won't, either.

PA

[newshound]

Yes but how old are the mowers? Certainly in the pre-electronic ignition days, loss of magnetism was one of the reasons that older mowers and motorbikes etc became more difficult to start. Seems to be less of a problem now, but 29 years is a good age.

[Brian Gaff (Sofa]

No compression or duff fuel would be my guess. Brian

[Brian Gaff (Sofa]

If you really are not getting a spark, then one might suspect that there is just not enough current to sustain one. You could have enough voltage to run a neon, but not make a spark due to some leakage or something in the windings. Brian

[Peter Able]

No compression or duff fuel would be my guess.

Good fuel, good compression.

As you say, it is probably something - matbe the capacitor in the ignition unit - just not up to the job.

What looks like a knock-off of the Little Wonder is due on Monday. Bet it won't last the 29 years of the Little Wonder.

Me, neither.

PA

[Muddymike]

Do you have a gas blowlamp? If so use that to feed gas into the air filter whilst pulling the starter. This method never fails to start my old 2 stroke machines.

Mike