Spark plug Questions.

[dramaminedragon]

I am changing the spark plugs on a 2007 5.0L TKS Mercruiser sr#OW667652. The original plug I removed was an AC DELCO 12607234. The MC service manual calls for a AC Platinum ACMR43LTS. The MC part # in the parts manual is 33-816336 but when I put this in it was changed to 41-BPR6EFS, which is a NGK plug. Question is what plug is the best to use? Also what is the gap? The service manual said 0.045in for the ACMR43LTS. Does this change with different plugs? Appreciate any help to get this answered.

 

[Fun Times]

Re: Spark plug Questions.

MerCruiser seems to be changing their part numbers and brand names around lately when it comes to spark plugs.

When looking up your info with your serial number the newest part number and name brand they are recommending to use is (NGK BPR6EFS) And MerCruiser newest part number is 33- 816336Q.
(IMO) NGK's plugs work very well with what just seems to be less problems over all.
The gap will be good at (0.045in) Also look at the top of the flame arrestor the gap info should be on the sticker.

And here are a few of the past part numbers they use to be.
1. 33 816336Q 00 ACT NGK BPR6EFS

2. 33 816336 01 SS NGK BPR6EFS

3. 33 83498813 02 SS SPARK PLUG

4. 33 854278 03 SS SPARK PLUG

 

[dramaminedragon]

Re: Spark plug Questions.

Thanks. I appreciate the explanation.

 

[cr2k]

Re: Spark plug Questions.

I agree NGK plugs are great quality. Plug gap is usually determined by ignition system and should be the same for any brand of plug.

AC plugs work good too and although we do use Champions in, occasionally, some applications (including GM block V-8s) I, personally, am less enthusiastic about them.

Be aware of the snake oil "specialty" plugs. You know the advertised on TV as having super spark or multiple sparks. The spark will travel the path of least resistance and unless these plugs are gaped exactly the same on each electrode you are just going to get one spark. Not to mention you need to have an ignition system of ample power to take any advantage of these plugs.