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View Full Version : How er. unique? Are spark plugs?



Blackshear
16th July 2008, 16:37
I have here a spark plug, that fits into the average 28cc centrifugal clutched, moped engine.

NGK CMR7H

A google result yields 6 NZ based sites, all for rc cars, hobby shops etc.
Now, what Chris would like to know, can a different spark plug be switched with said one?


Now, the problem is, it doesn't spark.
Yes, it is just the plug. *:Pokey:*
Pulled the starty rope thing and held the plug against the engine and it sparked on the sides.

I'm new to the whole sparkplug thing, so yeah I just wanted to know.
Will do my own net pondering as to why plugs foul and. Go all shitty. Somehow.



-----I have one being ordered into repco for me, and hopefully the fuel wont be stale and it'll all work sweet:headbang:-----

sefer
17th July 2008, 00:39
CHAMPION RZ7C will be fine too (same plug, different brand).

Even if it sparks it may need replacing, or you could have other issues.

awayatc
17th July 2008, 07:37
Apart from obvious differences in plugs appearances and sizes and even threads...... They also operate on different heatranges.....which is important:
a plug that is to cold will not give a full combustion.
A plug on the other hand that is to hot, will work well on short distances, but could blow a hole in your piston on a longer run.....
With some sparkplug brands the numbers go UP as plugs get hotter, other brands numbers go DOWN as plugs get hotter.
Stick with recommended plug-or its equivalent from another brand, you can't always tell when a plug is faulty.....especially on small engines plugs can fail frequently...
Good luck

CookMySock
17th July 2008, 08:20
you can kinda rejuvenate an old plug by heating hell out of the electrode with a gas torch. Get the bugger cherry red for a few minutes.

DB

CB ARGH
17th July 2008, 08:31
A google result yields 6 NZ based sites, all for rc cars, hobby shops etc.

There's some hardcore people out there that build scale cars (which are huge) using small petrol engines, such as one just like your engine.

Bit of random information for ya :D

davereid
17th July 2008, 08:36
There are two types of resistor plugs, one with an inductive type of resistor, and one with a conventional resistor. CDi systems, and magnetos will burst the conventional resistor type, often after only a few hours of use.

Get an NGK "Z" type plug, its designed for use ith CDi's or get a non resistive plug.