View Full Version : Odd looking spark plug query
bigfish1965
03-01-2002, 07:39 PM
My '98 Mariner 75 hp uses a plug without the usual gap. That is it has no gap, no anode. How does this type of plug work? The plug designation is BUHW-2. Are there superior types I can use?
T-Mac
03-01-2002, 07:41 PM
That is a surface gap plug. Been around a long time. They are fine.
perchjerker
03-01-2002, 07:43 PM
Yep, my old Chrysler outboard used them.
Be careful when you set the gap.:)
bigfish 1965
Here is some information on those spark plugs
A surface gap plug provides exactly what its name describes... a gap at the surface of the combustion chamber. The gap is a .050" annular configuration. The center electrode and insulator tip operate extremely cold (no heat range rating) and are, therefore, nearly impervious to pre-ignition. However, fouling deposits are always present and cannot burn away. These types have limited use in racing. A special ignition system with very high energy and a very fast rise time (CD) is required to fire the gap when fouling deposits are present