Thread: Plug issues?
07-11-2007, 07:57 PM #1
Guys; I just pulled my plugs at 5 Hrs. I placed a brand new identical plug right next to the used plug. See pics below. The new plug is an identical NGK PM9RB. My 250 runs great; I just wanted to see what a 5 Hr. plug looked like.
Observation: The new plug's washer is about .5mm thicker than the stock plug (new plug is on top). Can this cause a problem? The electrode will be that much deeper into the cylinder..
Also, there is a good amount of carbon on the end of the threads. Is this normal? My Honda ran it's first 10 hours on too much oil and it looked similar, but I may be overreacting given all of the oil level confusion. Should I put the new plugs in for kicks?
Anyone else want to post pics of their new or used plugs to compare?
07-11-2007, 08:07 PM #2
- Join Date
- Jan 2007
The washer is thicker because it hasn't been compressed yet, that's the purpose of it. Your old plugs look fine to me, running a little rich by I suspect that's by design. At the price of those plugs, I certainly wouldn't change anything out yet or if you do, send me your old ones
07-11-2007, 08:58 PM #3
- Join Date
- Jun 2007
He's totally right, It needs to be compressed is all
07-11-2007, 09:07 PM #4
07-11-2007, 09:28 PM #5
To properly "read" plugs, you must be WOT for ~5 minutes (which IMO is actually a little long) then hit kill @ WOT, then pull plugs and read the ring near the bottom of insulator.
07-12-2007, 12:23 AM #6
- Join Date
- Aug 2005
- Salinas CA
That`s an old method to read main jetting of your carburetor....
That does not apply to today's modern fuel injected engines.
You can use this method for all RPM ranges on today's F/I motors.
It wont tell you much, but you`ll get a good idea of overall mixture/burn condition of the plugs.
07-12-2007, 12:29 AM #7
the real deal is that you can't adjust, however the read still rings true.
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