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?

On 4/27/2022 6:41 PM, Michael Chare wrote:
> 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?

https://www.wersis.net/ngk/ngk-bpr6es.html

Resistor Yes
Resistor value 5 KΩ

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.

https://www.onallcylinders.com/2022/03/06/resistance-is-not-futile-dont-overlook-the-role-ohms-play-in-your-ignition-systems-spark-plugs-boots/

Paul

On 27/04/2022 23:41, Michael Chare wrote:
> 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?

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.

On Thu, 28 Apr 2022 08:41:40 +1000, Michael Chare
<mUNDERSCOREnews@charedotorg.uk> wrote:

> 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?

Nope.

On 27/04/2022 23:41, Michael Chare wrote:
> Is the coil likely to be damaged if I continue to use a spark plug
> without a resister?

No.

Bill

On 27/04/2022 23:41, Michael Chare wrote:
> 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?

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

On 28/04/2022 14:11, David Wade wrote:

> 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.

Ignition interference is very unusual these days.

Bill

Michael Chare <mUNDERSCOREnews@chareDOTorg.uk> wrote:
> 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?
>

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.

On 29/04/2022 06:19, Brian wrote:
> Michael Chare <mUNDERSCOREnews@chareDOTorg.uk> wrote:
>> 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?
>>
>
> 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.
>
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.

On 29/04/2022 06:19, Brian wrote:
> 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.

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

--
“Some people like to travel by train because it combines the slowness of
a car with the cramped public exposure of 
an airplane.”

Dennis Miller

On 29/04/2022 10:07, Michael Chare wrote:
> 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.

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

In article <t4e3pq$hf4$1@dont-email.me>,
David Wade <g4ugm@dave.invalid> wrote:
> 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.

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

--
*Young at heart -- slightly older in other places

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.