Another Ryobi trimmer question...

[John Rumm]

Like Tim I had the hedge cutter on the thing the other day and was in the process of doing some serious pruning on a large pampas grass that was getting (well had long since got to be more accurate) out of hand. Anyway, toward the end of the job the motor cut out - sounded like it might have run out of fuel, but there was about an 1/8th of a tank left. Still filled it up and attempted to restart. No joy. In the end gave up and thought I would try again when it was cold since it always starts from cold easily. But again nothing.

Checked the plug and there is a spark. Cleaned it to no avail. Swapped it for the one in my chainsaw and the chainsaw still works, but no difference on the trimmer. Fuel is getting in there, air filter is clear. What else can I try?

[The Natural Philosopher]

fuel is getting WHERE.

I had this and it turned out to be a clunk of gunk.

[Tim Watts]

John Rumm wibbled on Wednesday 07 April 2010 18:53

Thinking back to cars, could it be that the plug is sparking in open air OK, but in the cylinder under pressure it's becoming leaky and losing the spark (had that on old cars) - ie worth trying a new plug?

[John Rumm]

I swapped it for the plug in my chainsaw. The chainsaw ran fine with its plug and the trimmer one, and the trimmer ran with neither...

Another observation: took the back plate off the crankcase and noticed there was a small amount of fine metal flakes lose in there - nothing major- but what looked like a few small metallic flecks - not dissimilar from when one drops a small bit of hot solder onto a hard surface. Whether this indicates something serious has failed like a piston ring (still seems to have compression) or whether its just sloppy manufacturing quality I don't know.

[Harry Bloomfield]

FYI - If the fuel is getting 'there', the nose of the plug should be wet.

[John Rumm]

The priming bulb was also doing its stuff.

[Harry Bloomfield]

Therefore has to be be no/poor spark or not enough air.

[andrew]

From cold and using your normal starting technique : with the cylinder vertical pour a v small amount of engine oil into the plug hole to seal the bore. Try to start it. If it fires and then the plug fouls it will prolly be the ring seized in its bore.

Confirm by a peek through the exhaust port.

AJH

[John Rumm]

Air should be ok, I tried with the filter removed (which is only a small bit of foam rubber). The spark was visible - although perhaps not as strong as that with the same plug on the chainsaw.

[Mark]

I always try a squat of easystart on engine's that will not start, if it fires and makes an attempt to run its not anything catastrophic.  Holed pistons and sheared flywheel keys (so you get a spark but at the wrong time)  don't respond to easystart.