2000 7.4 Horizon plugs

[Nauti 97]

I have a 2000 380 Sundancer with Mercruiser 7.4 Horizon Engines.
The parts manual calls out Mercruiser part no. 803991, NGK BR6FVX spark plugs.
They have been discontinued.
Can anyone tell me what a very good replacement plug is?
Any issues with certain ones that I should stay away from?



Thanks in advance.

 

[K-DUB]

I have the same motors and just replaced the plugs this week. I was able to find them on Amazon. My friend uses Champion RV15YC4 in his.

 

[Firemedic181]

They are available on website Marinepartssource for $6.41 each. Or at least it showing they are available.

 

[Nauti 97]

They are available on website Marinepartssource for $6.41 each. Or at least it showing they are available.

Go on the website and put them in your cart and it says out of Stock!

 

[Bill Curtis]

My spark plug cross shows these as replacements:

• NGK BR6FVX replacement spark plugs
• Autolite 144
• Champion 3018
• Champion RV17PMC4
• Denso 5331
• Denso ITF20
• Mercury 803991
• NGK stk 5192

 

[techmitch]

My spark plug cross shows these as replacements:

• NGK BR6FVX replacement spark plugs
• Autolite 144
• Champion 3018
• Champion RV17PMC4
• Denso 5331
• Denso ITF20
• Mercury 803991
• NGK stk 5192

Champion plugs are good for Chryslers and lawn mowers but not much else.

 

[Pirate Lady]

We use Autolite (friends and I), after getting soaked in fog oil at winterize and changed every spring, what’s the point of fancy Iridium plugs.

 

[techmitch]

We use Autolite (friends and I), after getting soaked in fog oil at winterize and changed every spring, what’s the point of fancy Iridium plugs.

Those are trash also.

 

[Pirate Lady]

Those are trash also.

Autolite? Autocraft? Don’t remember. Can check. With all the sht I had with this boat, spark plug longevity is the least of my problems.

 

[Nauti 97]

Those are trash also.

tell me what you like!

 

[techmitch]

tell me what you like!

What ever the manufacture recommends. Many times that gets revised or updated and, if that info. is directly from the manufacture, then head the advise.

 

[scoflaw]

Merc customer support would have the latest info on what plug to run.

 

[Nauti 97]

Merc customer support would have the latest info on what plug to run.

that’s a good Idea
I will reach out to them.
Thanks

 

[douglee25]

The replacement plug is - NGK 2318 BR6FIX

 

[Pirate Lady]

What ever the manufacture recommends. Many times that gets revised or updated and, if that info. is directly from the manufacture, then head the advise.

Here’s what Merc recommends for mine and no way I putting Champions in.

 

[techmitch]

Here’s what Merc recommends for mine and no way I putting Champions in.
View attachment 126366

Wow, never seen that on a merc. Usually it's a AC MRXXX (43T) rings a bell.

 

[scoflaw]

Here’s what Merc recommends for mine and no way I putting Champions in.
View attachment 126366

Probably what they recommended in 91, bet they don't now.

 

[Pirate Lady]

That’s why I use the AC, well not me, the guy that winterize my engine.

 

[Pirate Lady]

Probably what they recommended in 91, bet they don't now.

Oh, the also recommended straight 40w oil, about to do change, thinking 10-40 Castrol semi synthetic. Mown back.

 

[scoflaw]

10-40 too thin for my liking unless you live in alaska. Is that what you've been using?