Spark Plug Gap Difference .060 and .045

[RedKnuckles]

I have 2006 Monsoon 340 non-catalyst engine.  Specs call for AC 41-932 plugs gapped to .060.  That plug no longer exists.  Bakes is suggesting ACDelco MR43LTS for non-catalyst engines, but these plugs are gapped to .045.  What to do?  Does it matter?

[csleaver]

I would recommend the AC 41-101 spark plug gapped at 0.060", which is the most current replacement for the 41-932.  The MR43LTS can be used, but they need to be gapped at 0.045" and will likely need to be replaced more often.

[RedKnuckles]

25 minutes ago, csleaver said:

I would recommend the AC 41-101 spark plug gapped at 0.060", which is the most current replacement for the 41-932.  The MR43LTS can be used, but they need to be gapped at 0.045" and will likely need to be replaced more often.

Thanks.  Would/could you also re-gap the MR43LTS to 0.060?

[csleaver]

No, the MR43LTS should be gapped at 0.045" 

[RedKnuckles]

Purchased the AC 41-101, $10ea.  Checked the gap and only two of the eight were gapped correctly at 0.060.  Others ranged from 0.065 to almost 0.070!

[csleaver]

They are supposedly pre-gapped, but I have also found they are not offen gapped correctly right out of the box.

[electricjohn]

I remember ENGINE NUT telling me years ago to gap any plug in my '03 Monsoon at .045". That .060" was more of a GM idea based on a 195* thermostat.

Edited September 5, 2022 by electricjohn
'03, not 04.

[Steve B.]

Not to change topic too much, but I've heard some folks use the longer plug where the "peanut" R43 plug is supposed to be used. That putting the electrode in more toward the center of the cylinder made a better fire.

Don't think I would do it without completely verifying it is safe to do.

Steve B.

[RedKnuckles]

8 hours ago, electricjohn said:

I remember ENGINE NUT telling me years ago to gap any plug in my '04 Monsoon at .045". That .060" was more of a GM idea based on a 195* thermostat.

Yeah, that is what the Indmar manual calls for, 0.060.  Since I have to re-gap them anyway, I figure I'll error on less than .060 rather than more.

[Loshie1056]

I had a similar issue and I talked with Indmar and they said it was ok to use the 41-993 gapped at 0.060 in lieu of the MR43LTS

[RedKnuckles]

The old original plugs that I pulled out (41-932) were all gapped exactly to 0.055.  The brand new 41-101 plugs that I put in were kind of all over the place right out of the box, from just under 0.060 to 0.070, so I did my best to gap them as close to 0.060 as possible.  Engine runs great.