Plugs for a 3.0l merc i/o

[snake91876]

what are the best plugs to run in a 3.0l merc mine is a
1987 model that has been rebuilt the valve cover says
a AC r43t i was wondering if this is what i need or a different one
since technology has changed in the last 20 years.

 

[chiefalen]

Re: Plugs for a 3.0l merc i/o

ac- mr43t

Champions-rbl-8

 

[Bondo]

Re: Plugs for a 3.0l merc i/o

Ayuh,...

AC, MR43T is Still the plug of Choice...

Anything New,+ Improved is a Waste of Money.....

 

[Don S]

Re: Plugs for a 3.0l merc i/o

Use either the AC or the NGK-BR6FS, I personally wouldn't use a Champion plug in any boat.
You wouldn't believe the number of boats that all that was needed to make run ok was replace the Champion plugs the boat owner put in.

 

[chiefalen]

Re: Plugs for a 3.0l merc i/o

I just gave the numbers AC is the better product.

 

[Rusty Boater]

Re: Plugs for a 3.0l merc i/o

Is that the same plug for all the Merc 3.0L? I have a 1999 Bayliner, Merc 3.0L, Alpha I and all the books show a serial number break and a different part number.

 

[Bondo]

Re: Plugs for a 3.0l merc i/o

Is that the same plug for all the Merc 3.0L?

Nope,...

The Really Old 1s use an 18mm plug, instead of the 14mm 1s of lately...
The Majority use the MR43T...
The Newest 1s, use a Longer plug, because of a Head redesign...
I Think it's MR43TLS, or MR43TS, or something like that....

 

[chiefalen]

Re: Plugs for a 3.0l merc i/o

1976 was when they started to used the mr43t. And it's still the same plug for you. Gap is .035