Coil Advice:

[MrMessy]

I have a 200 Honda that I have has a runabout. The overnight when I came out of work it would not start. Anyway when I got it home I was checking plugs, point etc and noted a arcing noise from the coil when the points where opened :!: I fitted a replacement coil, bike started and running great :D This coil makes the same noise if you flick the points open :!: Do they have an air gap to boost the spark :?:

[muddycoffee]

The points gap IS the way that the spark is produced on older engines.

If you charge a coil with a DC current, and break the circuit, the inductance of the coil causes a high voltage which is what is used for the spark.
Until electonic ignition came along, all petrol engines worked like that.

[MrMessy]

Hi Muddycoffee,
Thanks but I know that, the same way has in an A/C transformer the alternating current causes the flux to change. Coils would not normally make an arcing noise as it is to do with magnetic fluxes and has you say opening of the points causes the firing of the high tension side.

[muddycoffee]

I'm sorry for stating the obvious.
I wouldn't have thought that you should get an arching noise from a coil. Is it a brand new one or one from a breakers?
Are you sure that there isn't a crack in the insulation?

[wheelnut]

I used to use coil, but recently changed my boiler to a combi and now run it on gas :P

[muddycoffee]

I used to use coil, but recently changed my boiler to a combi and now run it on gas :P

arrr yer tekkin't pizz out'r us accent theeyen? Av not erd o' a coyil fiyered enjin foh fowatee yeearh

[Richie]

Do they have an air gap to boost the spark :?:

no, there usually filled with a cooling oil.
the noise is the voltage field collapsing when the contact's breaker open, or a very slight laps in the insoluation.

I used to have this problem alot on the old V8 landrovers, but since Her Maj's Army has move to deisel L/R's we don't get it anymore, just ERG/Turbo/FIP problems now...

hope this helps

[Sid Squid]

Noisy coil = insulation breakdown.

Some will continue working for ever like this, but it's extremely likely that the spark voltage will be reduced, only you can tell if this is having an effect on performance/economy.