Which spark plug for 89 OMC Cobra?

LAC_STS

Master Chief Petty Officer
Joined
Jul 1, 2010
Messages
895
Been hearing good things about the NGK plugs. On they're site is shows UR4 (6630)



What do you guys recommend?
 

zbnutcase

Commander
Joined
Sep 19, 2009
Messages
2,055
Re: Which spark plug for 89 OMC Cobra?

NGK's are excellent plugs, just about the only ones I use.
 

LAC_STS

Master Chief Petty Officer
Joined
Jul 1, 2010
Messages
895
Re: Which spark plug for 89 OMC Cobra?

Yea thats what I want to use I just cant figure out which one.

When I look up on theyre site I get a bunch of different part numbers.

When you look them up it lists all the OMC engines. If you select 5.7 Cobra you get.

UR4 - 6630 is the regular ones
UR4GP - 2869 is the premium NON Iridium ones

If you click on just 5.7 you get.

BR6FS - 4323 standard plug

And then if you look up Mercruiser ones its all different part numbers. What is the difference if they are all GM engines?

And what is the deal with the resistor? Some of the plugs say Resistor=yes?
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,226
Re: Which spark plug for 89 OMC Cobra?

AC MR 43T
been using AC marine plugs for years in my old 4.3 never had a problem....
 
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