A 'marine' spark plug is a spark plug for a marine engine. As far as any physical difference between a marine spark plug and a automotive spark plug.... Only the box that says 'Marine'.....
That said, you CAN NOT use a different spark plug designed for the automotive version of the same engine. You still need to use the recommend spark plug for the marine version of the engine you're working on.
I thought marine plugs were less likely to corrode/rust than standard auto plugs. Do they have a higher heat rating too for the higher stresses a boat motor undergoes?
You can check the various spark plug maker's web site for their differences in marine versus automotive plugs. Essentially boils down to some alloy differences and greater resistance to moisture environments, along with some performance characteristics suited for marine engines.
It's really very simple. Use the plug recommended by the manufacturer regardless. Now you don't have to worry about if it is a marine plug or otherwise. Guys that are a lot smarter than me decided #X is the correct item to use, so I take their recommendation even though it will cost me over $10.00 for each plug. :faint2:
Yup, I got me 2 boxes of the MR43T's just waiting to go into the engines in a few weeks. . . I think I bought them online, since the auto parts stores in my area don't cater to boats
ok i won't be a cheap ***** next time however for now i have NGK tr5 2238 installed that i purchased at auto zone. the old spark plugs were AC DelconMR43L will i be ok performance wise?
