Grass cutter Spark Plug resister

[Michael Chare]

When I tried to start my grass cutter today it kept stopping after about half a minute. The cutter has a Honda GCV160 engine. I could not find a fault with the fuel system so I consulted my computer which thought that the problem might be due to a faulty spark plug, which is a NGK BPR6ES. These plugs have an internal resister to reduce RF interference. As it happens I have some old car spark plugs which don't have resisters and are the same length. The grass cutter does run with these plugs but I was not sure how long I should do this for as I did not want the coil to get to hot because of increased current flow.

Is the coil likely to be damaged if I continue to use a spark plug without a resister?

[Paul]

Resistor Yes Resistor value 5 K?

There's no hint at power handling capacity though.

*******

And the bastards fool around with the stuff, and are stuffing resistors various places. There is one patent, with what looks like a snubber implemented at the body level of the coil. Many cooks adding ingredients to the broth.

Paul

[Fredxx]

No, the spark energy is peanuts to the current flowing in the primary. A non-resistor spark will deliver more spark energy but will also create more RFI.

[Jock]

Nope.

[williamwright]

No.

Bill

[David Wade]

No but length isn't the only factor, plugs are designed to run a certain temperatures as well.

The purpose of the resistor is to reduce Radio and TV interference, so if you run it when there is some sporting event on TV you risk physical abuse.

So I would say its worth ordering the correct type.

Dave

[williamwright]

Ignition interference is very unusual these days.

Bill

[Brian]

Have you tried cleaning and regapping the spark plug?

There is very little that can fail in spark plugs. They get gunged up etc, need regapping (less common now) but actual failure is rare.

I?ve seen photos of cracked insulators etc but never actually seen one in the flesh. Generally plug problems can be fixed by a good clean and resetting the gap.

In modern engines, plugs don?t even ?wear? away like they used to.

[Michael Chare]

Thanks for all the replies. I managed to cut the grass with my old car spark plug. There was no interference on my FM radio. I have ordered the correct replacement plug on ebay. The plug in the mower is 16 years old. It worked two weeks ago.

[The Natural Philosopher]

seen many cases of arcs dancing down the insulation...

[Vir Campestris]

If the plug is the wrong temperature setting you will find

• if too cold it will oil up

• If too hot it may burn a hole in the piston It can't be far out as you got as far as you did, but get the right one!

Andy

[Dave Plowman (News]

Think on modern engines, they also reduce interference to the engine ECU. Read reports of not using them causing misfires.