what spark plugs

[c03camson]

Hey Just wondering about what kind of spark plugs I need for my merc 5.0 mpi 2003 or where I can find that info. Boat is running like a champ but the outside of the plugs are all rusted, should I change them? No idea how long they have been in there. Thanks a lot

 

[Black as]

Re: what spark plugs

Try ringing your local marine dealer and give him full details of your engine, he will recommended a marine plug for you.

 

[Fun Times]

Re: what spark plugs

Hey Just wondering about what kind of spark plugs I need for my merc 5.0 mpi 2003 or where I can find that info. Boat is running like a champ but the outside of the plugs are all rusted, should I change them? No idea how long they have been in there. Thanks a lot

This information should be on top of your flame arrestor cover.
There should be a sticker with some of your engine specifications on it.

If not, Do you have a engine serial number?

 

[bruceb58]

Re: what spark plugs

Hey Just wondering about what kind of spark plugs I need for my merc 5.0 mpi 2003 or where I can find that info. Boat is running like a champ but the outside of the plugs are all rusted, should I change them? No idea how long they have been in there. Thanks a lot

You should be pulling those at least every other year so they don't get rusted stuck in the block.

 

[c03camson]

Re: what spark plugs

Serial number is 0M551478. Ill check the flame arrestor cover and/or talk to a local marina or something. Thanks

 

[Fun Times]

Re: what spark plugs

Serial number is 0M551478. Ill check the flame arrestor cover and/or talk to a local marina or something. Thanks

Also just so that you are aware, The number you posted (0M551478) is for your transom assembly, Your engine serial number that you will want to use for your engine is (0M603438).

Your engine Manufacture Date was on: 09/06/2002.

The spark plugs for your engine are (AC 41-932) And they should be pre gapped at (0.060)
Now for an (FYI) Mercruiser part number 33-884019 AC 41-932 Has Superseded over the years between the numbers listed below, So you have a choice, But remember they need to be pre gapped, Do not gap them your self. Good luck with it.

1 33 8M2018369 00 ACT NGK ITR4A15 @4

2 33 884019001 01 SS AC 41-993 @8

3 33 884019 02 SS AC 41-932 @8

The service manual for your engine is #31 V8 ENGINES 5.0, 5.7, 6.2 Part number 90-864260T00.

 

[c03camson]

Re: what spark plugs

You know way too much about my boat!! haha. thanks for the fyi thought that was the engine sn. much appreciated

 

[dan t.]

Re: what spark plugs

There is no such thing as a pre gapped plug,they come out of the box somewhere in the general vicinity of the proper gap but can vary as much as .010 or more. Get a wire feeler gauge and check and adjust them

 

[Fun Times]

Re: what spark plugs

There is no such thing as a pre gapped plug,they come out of the box somewhere in the general vicinity of the proper gap but can vary as much as .010 or more. Get a wire feeler gauge and check and adjust them

Yes you are right, You should check them, But the trick here is to try to find the spark plugs that are already gapped to this particular engines requirements from the factory.

This should be somewhat easy to do in this situation, Because the style of spark plugs your engine calls for can be found already set at (0.060) from the factory without the need of resetting the gap, That is as long as the spark plugs have not been damaged in any way.

Below is some basic information that I made my statement off of for this particular situation.

This is right from AC Delco Catalog Parts Search Results.
Part Number: 41-993
Product Notes:
[Platinum Spark Plug]; Gap pre-Set at factory, do not re-Gap ; .060 GAP

Should I gap my Iridium Plugs?

The manufacturers say NO.
This is because most people do not know how to properly gap a spark plug, and the center electrodes on the ultra-fine iridium can easily snap if mishandled. There is no warranty for snapped center electrodes. The manufacturers say an iridium spark plug will run so much better than a traditional plug, even if it is not gapped for that motor, that they would prefer you just leave it rather than risk snapping the center electrode.
Personally, we at ChampionSparkPlugs.com, gap our iridium plugs for our own vehicles (we?re rebels). If you insist on gapping your iridium plug, please refer to Proper Gapping for instruction.
http://www.championsparkplugs.com/faqmain.asp

Do I need to Gap my plugs?

Maybe, but likely not. Many plugs are pre-gapped for their most popular applications, however, the gap can be altered if the plug is dropped or mishandled in packing/shipping. Therefore even if the plugs are supposedly preset for your motor, it is always wise to check the gap on each plug prior to installing. For information on how to adjust the gap see Proper Gapping.

It is not recommended that you adjust the gap on multi-ground plugs.

For information on gapping Iridium spark plugs see FAQ question Should I gap my Iridium Plugs?
http://www.ngk.com/faqmain.asp


Now I know what your thinking, Cool less work to do on my spark plugs, But wait till you see the price of each spark plug. $$$ X 8 = Happy Boating.

 

[achris]

Re: what spark plugs

... But wait till you see the price of each spark plug. $$$ X 8 = Happy Boating.

But they do last 5 times longer (supposedly), so that makes them cheaper than conventional plugs.

Just my 0.02.

Chris........

 

[Fun Times]

Re: what spark plugs

But they do last 5 times longer (supposedly), so that makes them cheaper than conventional plugs.

Just my 0.02.

Chris........

lol, Not at mercruisers MSRP of: $19.30 for each plug.

Mercs latest plug number.
Item Number: 8M2018369
Description: NGK ITR4A15 @4

Not to mention there has been a few sets of these spark plugs that have made these engines misfire or pop like a backfire would sound within 200 hours or so.

 

[c03camson]

Re: what spark plugs

So I found some AC 41-993 plugs for like $7 on summit racing. Also, I was on amsoils website and typed in my engine and all that, they gave me NGK7164. This is an iridium plug, is iridium more beneficial or should I stick with AC delco platinum?? The NGK's dont cost much more. Thanks