4.3L Correct Spark Plugs Have Changed?

[MarkD]

Hopefully this might assist a few people here that have the same engine I do.... I recently found out a Mercury Service Bulletin No. 2006-03 that states the correct plugs for the 2006 and later 4.3L carberated engines are as follows:

"The recommended service replacement spark plugs for these engines are non-platinum AC MR43LTS (P/N 33-884019) or NGK BPR6EFS (P/N 33-816336)."


Evidentally, the originals were shipped with Platinum plugs and the gaps are far different. See below:

"MerCruiser 4.3L, 5.0L, and 5.7L carbureted engines are shipped new with platinum AC 41-932 (P/N 33-884019) spark plugs, soon to be superseded by AC 41-993 (P/N 33-884019001)."



Can someone confirm that this is accurate? I would prefer to get the plug #'s right from the get-go. I will also call the dealer....

 

[fc3]

I think platinum plugs in a marine engine are overkill. No one is going to leave the plugs installed for such a long time that platinums will have any advantage over standard plugs. If the MR43LTS is OK for the engine, use them. They'll light the fires just fine and are cheap enough to replace every few years.

Best regards,
Frank

 

[MarkD]

Yeah, thats what I thought too. I just wonder why they decided to "formally" change the proper plugs from platinum to the plain vanilla type. I wonder of they did some harm somehow?? do these plugs run hotter?