4.3LX Spark Plugs

[dmaxx]

I have a 4.3LX with ser. # F606415. I am confused on which spark plugs I need to get for it. I have read from searching that if you have Vortec heads you need the longer plugs. I think I have Vortec heads because it says it on the valve cover, but on another thread I read, it says that the intake bolts will be straight down if you have Vortec heads. M

 

[dmaxx]

Re: 4.3LX Spark Plugs

Damn phone. To finish my post...my bolts are angled into head. I searched it on mercruiser parts express with my serial number and it comes up with the short plugs. I just want to double check with everybody that I am using the right plugs because I have another thread open for WOT rpm problem. Thanks.

 

[Bondo]

Re: 4.3LX Spark Plugs

Damn phone. To finish my post...my bolts are angled into head. I searched it on mercruiser parts express with my serial number and it comes up with the short plugs. I just want to double check with everybody that I am using the right plugs because I have another thread open for WOT rpm problem. Thanks.

Ayuh,.... I'm guessin' you've got a Pre-1996 motor, which uses the MR43T spark plugs...

The name Vortec was used for years, before what We now know as Vortec heads were even invented...

The Vortec heads only have 4 bolts per side, on the intake, pre-vortec uses 6 per side...

 

[Don S]

Re: 4.3LX Spark Plugs

According to your serial number, as Bondo said, you need the AC-MR43T or NGK-BR6FS

 

[canyonken]

Re: 4.3LX Spark Plugs

FWIW - I bought the NGK BPR6EFS plugs for my engine and they where NOT the correct ones. I had to buy different plugs but I don't remember what theyare since they are IN the engine. I have a 96 Sea Ray with MCM 4.3LX Gen+ serial# OF803642. Is my engine pre-96 ??

 

[dmaxx]

Re: 4.3LX Spark Plugs

Thanks for quick replies. I saw the intake bolts and got confused. I appreciate the explanation Bond-o. I just got done putting the short ones in.

 

[dmaxx]

Re: 4.3LX Spark Plugs

I pulled the dcap and saw a little bit of corrosion on the points and on the rotor where the coil wire connects it is black. Should I just clean it up or put a new dcap and rotor on?

 

[achris]

Re: 4.3LX Spark Plugs

FWIW - I bought the NGK BPR6EFS plugs for my engine and they where NOT the correct ones. I had to buy different plugs but I don't remember what theyare since they are IN the engine. I have a 96 Sea Ray with MCM 4.3LX Gen+ serial# OF803642. Is my engine pre-96 ??

You have a Gen+ engine, 1996, and the right plugs for you ARE the BPR6EFS... Who told you they are the wrong ones?

Chris........

 

[canyonken]

Re: 4.3LX Spark Plugs

Chris - no one told me. When I went to install them they where wrong size and did not match the ones that came out. If I remember right - they where too skinny. I was kinda surprised. I still have the BPR6EFS plugs sitting the garage for past two years or so ....

dmaxx - what where the numbers on the smaller plugs you just put in ?
Your engine serial number is # F606415 and mine is # OF803642 - maybe we don't have the same engine. I thought we did.

 

[achris]

Re: 4.3LX Spark Plugs

Chris - no one told me. When I went to install them they where wrong size and did not match the ones that came out. If I remember right - they where too skinny. I was kinda surprised. I still have the BPR6EFS plugs sitting the garage for past two years or so ....

dmaxx - what where the numbers on the smaller plugs you just put in ?
Your engine serial number is # F606415 and mine is # OF803642 - maybe we don't have the same engine. I thought we did.

DMAXX: You have a Gen II engine.. . Correct plugs are NGK BR6FS/AC MR43T

CanyonKen: You have a Gen+ engine... Correct plugs are NGK BPR6EFS/AC MR43LTS

This is from both the Merc service manual AND the Merc parts catalog.... They can't both be wrong...

Chris........

 

[canyonken]

Re: 4.3LX Spark Plugs

thanks Chris.

I did an internet search for the difference between a Gen II and a LX Gen+ but all I got where parts catalogs.

What is the difference between all of these engine codes ?? Some have LX, some don't.

 

[achris]

Re: 4.3LX Spark Plugs

The best place to read about all the different incarnations of the V6 are here -> http://www.hotsixes.com/index.php?option=com_content&view=article&id=14&Itemid=12

This is one of the best I have read... Basically the Gen II engine (up to 1996) was with a balance-shaft, but not vortec heads... (it had the plastic 'vortec' covers and the centre bolts, but there were the old heads slightly revamped). The Gen+ engines (from 1997) had the proper Vortec heads, and of course different spark plugs.... And about 15hp more

Chris.......

 

[dmaxx]

Re: 4.3LX Spark Plugs

Thanks Chris. I put the NGK BR6FS's in there last night. I just have to get some time to take it out and see how well it runs. Hopefully today I will get it out.

 

[Don S]

Re: 4.3LX Spark Plugs

This thread is a perfect example of why you should go by serial number, not year, nor what someone else uses.

Both dmaxx and CanyonKen have 1996 engines.
There were 2 different 4.3LX long blocks used in 1996. Look at the picture below, and you can see the serial number breaks from one model to the next.