Which Spark PLugs

[maximedelo]

HI, I have a merc 350 5.7 MPI 2004 and I wanted to know if those spark plugs were ok for my engine.Here is the ngk code i bought TR55GP

thanks

 

[Bondo]

Re: Which Spark PLugs

Ayuh,... Never heard of That # before,...
I prefer AC Delco myself,...
Your heads should be Vortecs, which use the extended tip plugs,...
AC Delco, MR43LTS I think is the #...

 

[maximedelo]

Re: Which Spark PLugs

thanks for the reply. The only problem is that i already bought them and I went on the ngk website.

Can anyone confirm it would fit?

thanks

 

[Alpheus]

Re: Which Spark PLugs

Check them against your old plugs and see if they are the same...

 

[Bondo]

Re: Which Spark PLugs

Ayuh,... After abit of googling, it appears it'll fit any of the Chevys built after 96,...
So,... yes, they'll screw in,+ Run...
But,...
They're platinum tipped plugs, probably set to the wrong gap, because of the different ignition used on the Chevys, Vs. the Mercruiser T-Bolt...
Regappig 'em will scratch the platinum, causing it to burn off, or worse...

Any of the fancy smancy sparkplugs sold as improvements to automotive applications,...
Are anything But that in a Marine application...

There's No real or imagined gain from wasting money on the Wrong sparkplugs for Any application...

I'd return 'em,+ get the Right 1s myself.....

 

[maximedelo]

Re: Which Spark PLugs

ok thanks guys. so basically, which one would you recommend me with part #
thanks very much

 

[Don S]

Re: Which Spark PLugs

The MPI engines call for the AC 41-932 platinum spark plug which is now NLA, and was changed to an AC 41-993 number. Click here for the service bulletin covering the change.
AC, 41-993 (Platinum)Replaces AC 41-932
Mercury Part # 33-884019
NGK PZTR5A-15

Fits 2001 and newer MCM/MIE 4.3L MPI, 5.0L MPI, 350 Mag MPI & MX 6.2L MPI engines with ECM 555 (s/n 0M300000 and up)

Just to prevent any confusion, you do not have the Thunderbolt ignition system on your MPI engine, only the carbed and some TBI engines use the Thunderbolt V system.

 

[Bondo]

Re: Which Spark PLugs

Just to prevent any confusion, you do not have the Thunderbolt ignition system on your MPI engine, only the carbed and some TBI engines use the Thunderbolt V system.

Sorry,... I guess I missed that part....

 

[maximedelo]

Re: Which Spark PLugs

Great!! Thanks Don S. My engine serial is 0M6555**.

If I understand what's in the service bulletin I should use AC 41-933 or NGK BPR6EFS (at the bottom of the bulletin)?

Thanks

Max

 

[Don S]

Re: Which Spark PLugs

NO, the only place it mentions BPR6EFS is under the heading of carbed engines.

Go up to my post, I posted the NGK number in BOLD letters. PZTR5A-15

 

[maximedelo]

Re: Which Spark PLugs

great Don, Thanks very much!

What would be your preference? AC or NGK? Or there is no diff?

Thanks again

 

[Don S]

Re: Which Spark PLugs

I have not seen them with anything else other than AC and Champions (Volvo likes Champions). Had nothing but troubles with Champs till I went back to the AC plugs. Then the Volvo engines ran fine just like OEM .

 

[maximedelo]

Re: Which Spark PLugs

Thanks very much Don for your advice!! Much appreciated. I know who I need to contact if I have other questions.

Max