Simple Diagnostic Skills Test

[glasseye]

So, gurus: what was the problem?

Kill switch/cable was rusted in "kill" position.
Gurolin

[Westy78]

Bad plug wire shorting to ground before reaching the spark plug.

[glasseye]

Close. Very, very close. But no cigar. :)

[ruckman101]

No gap on the spark plug.

neal

[Westy78]

No gap on the spark plug.

neal

Oh yeah, that's good!

[ruckman101]

Been there.

neal

[glasseye]

Visual inspection of the plug revealed no gap fault.

[asiab3]

Plug wire end/plug end touching ground? My old Briggs&Stratton go kart had a safety like that...

[ruckman101]

Hmmm, stymied.

neal

[Amskeptic]

So, gurus: what was the problem?

Kill switch/cable was rusted in "kill" position.
Gurolin

Did I accidentally EDIT your initial post when I was just answering it? Too many buttons and stuff in this God Administrator Forum panel. My apologies!!

SO. Was it the kill switch cable rusted in "off" position??
Colin

[glasseye]

Crap. Not only did you edit my initial post, you DELETED IT.

Now, we'll NEVER know what was causing my mower to not start.

There is no kill switch on my mower, other than the ignition switch, which is both new and known good.

Symptoms were:

Cranks, but no start. A few pops and splutters.
Plug body shorted to ground: no spark.
Plug body held a half inch away from ground: big, fat spark between plug and ground.

So? What next?

[Amskeptic]

Crap. Not only did you edit my initial post, you DELETED IT.

Now, we'll NEVER know what was causing my mower to not start.

There is no kill switch on my mower, other than the ignition switch, which is both new and known good.

Symptoms were:

Cranks, but no start. A few pops and splutters.
Plug body shorted to ground: no spark.
Plug body held a half inch away from ground: big, fat spark between plug and ground.

So? What next?

You got a magneto on that bad boy, or some fancy electronicsprinterlike ignition? Crazy no spark grounded plug makes me wonder about polarity of electrical . . . you do not have an isolated engine due to rubber mounts > broken ground strap.

Colin

[glasseye]

Gots no magneto. Gots simple battery-and-coil ignition. No points, though. Some kind of electronic "distributor" in there somewhere.

My reasoning went like this:

The spark would prefer to jump from plug body to ground rather than across the gap. Hence, a short between the two electrodes on the plug. When the plug was body was grounded, the spark went straight from center electrode to ground invisibly.

A quick bout with the multimeter confirmed my suspicion. Physically invisible, but electrically there.

Off I went, plug in hand to FLAPS, returned with a nice new plug, installed it and turned the key.

Vrooooom! Hey. It's a Honda.

Westy78 and ruckman101 were the closest. They can fight between themselves over who gets the old plug as their consolation prize.

[ruckman101]

Shoddy manufacture? Was it a new plug, or one that had been working and failed.

neal

[glasseye]

The factory original.

The Honda mower is at least 12 years old and the failed neutral interlock switch that caused the massive disassembly is the first problem I've ever had with it in all those years.