05' 5.0mpi Spark Plugs

OllieC

OllieC

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Mar 11, 2013
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N.W. ‘Sconnie
Boat Info
Sara Belle
2005 Weekender 215
Engines
Mercruiser 5.0 mpi, Bravo III
engine #0W037286

I'm trying to figure out the proper plugs to order. I see the Mercury Service Bulletin 2006-03 which calls out 33-884019 / AC 41-932. The bulletin is from 2006.

When I look up the 33-884019 it says the following;

"33-884019 SPARK PLUG (AC 41-932) has been superseded to part number 8M2018369" on Mercruiserparts.com

33-8M2018369 is an Iridium Spark Plug NGK ITR4A15. I just wanted to verify that Iridiums are the proper replacement.

Thanks,
Ollie
 
Merc regularly supersedes which plug they feel is best for that motor. Call their customer service number.
Yes they are def. iridium's
 
Are the current plugs bad? If they're good, no need to change.

Another way to look at this... if you're happy with the way the engine was running and the plugs "read" well, put the same type back in.
 
Lazy Daze said:
Are the current plugs bad? If they're good, no need to change.

Another way to look at this... if you're happy with the way the engine was running and the plugs "read" well, put the same type back in.
Click to expand...
I am in the process of replacing the manifold, risers and elbows so I figured I would just replace the spark plug wires and plugs while it was open. (process meaning they're on order)
No, everything runs fine.
Also, I am replacing the starter. Everything is tight so I figured with the manifold completely off I can reach the other stuff and just replace it as preventative.
 
There the expensive plugs cause thats how GM ships the motors. Same plug used in cars for emissions,not cheap
MR43LTS do the same job with no loss in performance and run cooler preventing ping and detonation
 
Bt Doctur said:
There the expensive plugs cause thats how GM ships the motors. Same plug used in cars for emissions,not cheap
MR43LTS do the same job with no loss in performance and run cooler preventing ping and detonation
Click to expand...

I can't stress the above enough - the "original" plug that is no longer made was "cooler" than the replacement plug it crosses to. Indmar has issued TSBs to its customers requiring the use of the above referenced plug. The 5.0s in my former 300 had to work hard, and I lost one of them due to detonation, in part due to the too hot plugs
 
OllieC said:
I am in the process of replacing the manifold, risers and elbows so I figured I would just replace the spark plug wires and plugs while it was open. (process meaning they're on order)
No, everything runs fine.
Also, I am replacing the starter. Everything is tight so I figured with the manifold completely off I can reach the other stuff and just replace it as preventative.
Click to expand...
One of the tougher jobs on those motors is replacing the plugs with the manifolds in the way................One of the easiest jobs is replacing the plugs while the manifolds are removed!
 
OllieC said:
I am in the process of replacing the manifold, risers and elbows so I figured I would just replace the spark plug wires and plugs while it was open. (process meaning they're on order)
No, everything runs fine.
Also, I am replacing the starter. Everything is tight so I figured with the manifold completely off I can reach the other stuff and just replace it as preventative.
Click to expand...
Sure, can't hurt to do it. The wires should be pretty easy to do at any time - if you wanted to skip something, that is. But if you don't know when it was done last, again, can't hurt.
 
I just ordered the NGKs - were those incorrect?
 
Ididntdoit said:
I can't stress the above enough - the "original" plug that is no longer made was "cooler" than the replacement plug it crosses to. Indmar has issued TSBs to its customers requiring the use of the above referenced plug. The 5.0s in my former 300 had to work hard, and I lost one of them due to detonation, in part due to the too hot plugs
Click to expand...
Merc didn't issue a TSB about it and doubtful that was your problem, they're not going to recommend a plug that could burn your engine down. More than likely it was caused by a lack of water overheat or a fuel restriction leaning it out.
 
I just did this job manifolds/risers/ elbows and took advantage of the access I have a 5.0 TKS all I found was NGK-BPR6EFS I’m hoping these are correct now that you pointed this out.
 
I'm about to do this on the same engine and looked up the same way you did. Bought the NGKs from Advance Auto since they had a 20% off coupon. According to my son who's apprenticing in a marina service shop this spring and summer, that's what they're installing in the Merc 5.0 MPIs too.
 
I have all the maintenance records from the 205 sport and the marina did install the NGK’s at one point but they also installed AC Delcos I also went to advance and got them for about $3 bucks I believe sounded fine today with the first start up of the season.
 
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