Recommended Spark Plug failed.

[ronaca88]

Here's another history of my boat. Two weeks ago I changed the spark plugs to the recommended in the manual AC-41993. I changed them because I was having trouble starting the engine, after that, It results that it was nothing to do with the spark plugs but I leave it anyways. We cruise, wake and tow on the weekend and everything normal.

This weekend, I try to start the engine and It only cranks and cranks. I call the mechanic, and after an inspection he change the spark plugs even when I tell him that they were new.

He put some new sparkplug convencional cooper core, (non-platinum, neither iridium) and the engine starts. He tell me to buy the right sparkplug but not to buy any platinum or iridium. He recommended AC Delco.

The cuestion is, which is the AC Delco correct sparkplug for my engine? Does anyone have trouble with the AC.-41993??

Engine: 2014 5.0 MPI Mercruiser
Serial: 2A189803

 

[alldodge]

Here's another history of my boat. Two weeks ago I changed the spark plugs to the recommended in the manual AC-41993. I changed them because I was having trouble starting the engine, after that, It results that it was nothing to do with the spark plugs but I leave it anyways. We cruise, wake and tow on the weekend and everything normal.

This weekend, I try to start the engine and It only cranks and cranks. I call the mechanic, and after an inspection he change the spark plugs even when I tell him that they were new.

He put some new sparkplug convencional cooper core, (non-platinum, neither iridium) and the engine starts. He tell me to buy the right sparkplug but not to buy any platinum or iridium. He recommended AC Delco.

The cuestion is, which is the AC Delco correct sparkplug for my engine? Does anyone have trouble with the AC.-41993??

Engine: 2014 5.0 MPI Mercruiser
Serial: 2A189803

Your engine should be using Merc 8M2018369, NGK ITR4A15, AC 41-101

Also just as a note your engine has a crab style distributer cap (I call them crap caps). These caps will stop working for no reason and you can find nothing wrong with them, but if a new one is installed, it fires right up

 

[Bt Doctur]

MR43LTS too

 

[DeepBlue2010]

To AllDodge, BT and all the experts, was the mechanic right in his statement? If a platinum or iridium - direct equivalent - to the original NGK was installed, is there anything wrong with that?

 

[Bt Doctur]

the mercruiser motors come with those plug because its what GM installs in their engines. considering we don't leave them in for 100,000 miles and tend to change them every 2 years . Corrosion plays havoc with the sparkplug shells. Leaving them in too long results in removing the porcelin and shell but leaves the threads in the head Plus $27.00 for a set is a whole lot cheaper than platinum or iridium

 

[alldodge]

MR43LTS too

BT I was thinking it should be the one you listed but the NGK didn't cross to it. I'll admit that I only looked at the Mercury OEM site and not mercruiserparts for the Merc part number

 

[Bt Doctur]

[h=2]Replacement spark plugs for AC DELCO mr43lts:[/h]

Autolite	103
Beck Arnley	176-5180
Beru	14KGR-6KQU
Bosch	+14
Brisk	GR14ZC
Champion	RS12YC
Denso	5032
Denso	5326
Denso	IT20
Denso	T20EPR-U
Denso	T20EPRU
Denso	VT20
Denso stk	5032
Eyquem	RC52LJS
Fiat	7910247204
General Motors	5614210
Iskra	FET65PRS
Magneti Marelli	T7LCR
Motorcraft	AGRF12C
NGK	BPR6EFS
NGK	TR5
NGK stk	2238
Splitfire	SF10D
Torch	Q6RTC
Unipart	GSP2006

Brand Model

 

[Bondo]

BT I was thinking it should be the one you listed but the NGK didn't cross to it. I'll admit that I only looked at the Mercury OEM site and not mercruiserparts for the Merc part number

Ayuh,..... NGK probably don't make a conventional spark plug, with an Alloy body/ shell,...

The Alloy body ain't rust proof, but it's rust resistent,....
They stay metal colored, not rusted for many years up here on the sweetwater seas,....

I'm with BD,.... I use nothin' but the AC Delco MR series spark plugs in Chevy based boat motors,....

I don't change the spark plugs every couple years either,....
I look at 'em every couple, but only replace 'em, when the corners on the electrode start roundin' over,....
If they're still sharp, they go back in for another lap,....

 

[alldodge]

I'm with BD,.... I use nothin' but the AC Delco MR series spark plugs in Chevy based boat motors,....

I was using nothing but MR my self until I git this new motor in the cruiser, and he said to use the NGK, but don't know which ones yet, haven't looked

I don't change the spark plugs every couple years either,....
I look at 'em every couple, but only replace 'em, when the corners on the electrode start roundin' over,....
If they're still sharp, they go back in for another lap,....

I go one step further, if I don't see/since anything to concern me I don't even pull the plugs out. Bought my 95 Rinker new, and pulled the Champion original plugs out of the motor two years ago, they still looked fine, but replaced them with MR43T. Had no effect but what the hay, they were 18 year old plugs

 

[Bondo]

they were 18 year old plugs

Ayuh,..... Ya got Me beat,.....

I only changed mine this year, 'cause she developed a skip fishin' one day,....
Blew it out, 'n it run Better, but like ya say, it deserved a look,....
Threw in a new set, 'cause I couldn't remember how many years it's been,...
Only had one used set in the boat toolbox, so this is probably the 3rd set in 16 years or so,...

For the boss's fleet, it's new plugs in new motors, or when an issue happens,.... not often, but Always MR's,...

 

[ronaca88]

I put the AC Delco 41993 because the manual says. They just work a day. Then the engine just crank but wont start.

I put new sparks plugs and the engine run fine. I have to change the sparks for the correct one, but is there a posibility that the hole pack were wrong or I should look for another problem?

 

[alldodge]

Something is wrong with the manual, the Merc site listed the NGK and Merc number, no mention of the ones you show. The cross reference does not show them either

 

[ronaca88]

I think I will try the mr43tls and see how they go. I'll keep you posted.

Regards.

 

[FreeBeeTony]

I bought 2 sets of MR43LTS about 8 yrs ago for my Vortec SBC.
I rotate them every other year and just clean them with a wire brush.

 

[Fun Times]

I think I will try the mr43tls and see how they go. I'll keep you posted.

Regards.

Personally with the ignition and catalyst exhaust system you have plus you should still be under warranty (< & and if not, you're still close enough that Merc might still help you out in some cases as long as everything is still/stays within OEM specs) I would not recommend any spark plug other than the NGK. The CAT system is pretty sensitive to many item changes especially engine oil.

The AC 41-993 that you should have had installed from new has now changed to the NGK ITRA15 when ordered from Mercruiser...So either plug brand would be fine but NGK would be what a Merc dealer should install at the time. Also be sure to look on top of the engine specifications stickers as there should be the recommended spark plug information that you really should follow.

When you installed the new spark plugs, did you check and/or re-adjust the gap? Those spark plugs are very sensitive to breakage during checking/adjusting so dame is possible if done incorrectly.

8M2018369

8 Qty

SPARK PLUG, (NGK ITR4A15)

Bulletin No. 2006-03 - JustAnswer

It's hard to believe that you'd really be having so many spark plug problems with a 2014 engine model. What do they look like when you pull/ed them out? How many hours on this engine?

Good luck.

 

[ronaca88]

They look like the image. I think this is good, but im curious why just changing the sparks, the engine run. The engine has 140 hours. Does the hot weather affect the spark plugs? We have in summer about 100 F to 110 .

 

[FreeBeeTony]

Not sure if it's the pic, but the gap looks kinda large in the 1st pic.
Is the gap correct?

 

[ronaca88]

Yeap, .060" as the manual says.

 

[Volphin]

Another vote for MR43LTS.

 

[Fun Times]

Just so all this is clear to ronaca88, Please know that the recommended spark plug heat range is different between the NGK ITR4A15 and AC-Delco's MR43LTS due to the "correct" cross reference NGK spark plug of MR43LTS is NGK BPR6EFS which you can see changes the NGK heat range by 2 using the info quoted below.

The heat range numbering system used by spark plug manufacturers is not universal.
For example, a 10 heat range in Champion is not the same as a 10 heat range in NGK nor the same in Autolite. Some manufacturers numbering systems are opposite the other - for Champion, Autolite, Bosch and AC-Delco, the higher the number, the hotter the plug. For NGK, Denso and Pulstar, the higher the number, the colder the plug. When making spark plug heat range changes, it is better to err on the side of too cold a plug. Running too cold a plug can only cause it to foul out, whereas running too hot a plug can cause severe engine damage.
Choosing the Right AC-Delco Spark Plug ?
The first number denotes thread size and the second number indicates heat range. Thread sizes are: 4 = 14 mm 8 = 18 mm 10 = 10 mm 12 = 12 mm 2 = 1/2 inch taper 5 = 1/2 inch 6 = 3/4 inch 7 = 7/8 inch. Heat ranges are: 0-1-2-3-4-5-6-7-8-9: Cold (0) ?? Hot (9). The higher the second number, the hotter the plug.

New Numbering System:
AC-Delco precious metal spark plugs ? platinum and iridium ? use an all-numeric identification code. The numeric code does not correspond to the heat range of the plug as it does with conventional spark plugs. This numbering system was developed to avoid any confusion between precious metal plugs. When replacing a precious metal plug, it is not recommended to select a plug with a different code number. For example, spark plug 41-806 can be identified as: 41 = ACDelco product line (41 is the spark plug line) 806 = Type of spark plug The type of spark plugs are: 100?199 = Iridium* 600?699 = Resistor 800?999 = Double Platinum (*Exception: 41-985 is an iridium plug).

AC DELCO 41-101 = NGK ITR4A15:, http://www.sparkplug-crossreference....C_DELCO/41-101
NGK ITR4A15: = http://www.sparkplug-crossreference....NGK_PN/ITR4A15
AC DELCO MR43LTS: =, http://www.sparkplug-crossreference...._DELCO/MR43LTS
DELCO 41-810: = NGK Spark Plug OEM # 3623 AKA BPR6EFS which also = http://www.sparkplug-crossreference....C_DELCO/41-810
Should you decide to get a little more within your recommended heat range while using a conventional spark plug then AC DELCO R44LTS would be an option as there are some closer heat range numbers that seem to cross reference a little bit better. http://www.sparkplug-crossreference....C_DELCO/R44LTS < The Platinum Spark Plug
Part Number is 41-942

http://www.ngk.com/product.aspx?zpid=9838

The plug in you hand doesn't look to bad as it don't seem like it was running to rich or anything. What is the number/s on the plug in your hand?