OK for the spark plug gap to be slightly off from recommended?

[DJ_Allatoona]

1986 Mercury 75hp. I've always used Champion L76V spark plugs (surface gap). I couldn't find them in a store today, so I got an Autolite brand that is closest to the specs of the Champions.
The difference is: the Champions have a gap of .05, the Autolite gap is .052
I wonder if my smoky, grouchy old motor is going to notice the difference or even care about that different gap spec.
Should I get the proper plugs ASAP, or wait to see if these replacements run OK?
And someone please explain to me (as if I was a child) the differences from one spark plug to the next. Thanks.

 

[airshot]

Why not the Quicksilver brand the mfg recomends ? In my experience, Champions only work best in OMC ( older type 2 stroke) engines, where NGK ( Quicksilver) seem much better in Mercury engines. To answer your question, the .002 difference in gap means nothing.

 

[Dukedog]

try these.. its what merc calls for... ngk buhw-2 are no more.

33-97182Q - NGK BUHW - 2 superseded to SPARK PLUGS (CHAMPION SPARK PLUGS) - L78V Sold individually.

 

[jimmbo]

The NGKs that came in my 84 115 when new, were still in it in 1998, with 700hrs on them, when I traded the Boat and Motor on a new one

 

[Dukedog]

The NGKs that came in my 84 115 when new, were still in it in 1998, with 700hrs on them, when I traded the Boat and Motor on a new one

 

[Chris1956]

I do not think Mercury ever specified a conventional spark plug to replace a surface gap one, in your motor.

I would stick with the surface gap plug. They look to be avail in lots of places.

 

[Texasmark]

I do not think Mercury ever specified a conventional spark plug to replace a surface gap one, in your motor.

I would stick with the surface gap plug. They look to be avail in lots of places.

My service manual covering 90 and 115 2 strokes plus others shows both types of NGKs in the specifications section. I run the gapped version and like them much better, especially on the 115 2+2...lower 2 cylinders stay cleaner and come online faster.

 

[Chris1956]

Mark, do you have a listing for a conventional plug for a 1986 motor? I never saw one. Merc did specify conventional plugs for newer motors, however.

 

[Chris1956]

As was said, surface gap plugs last a real long time. I have a set that I bought new 2 years ago. The ones in the motor are fine, so the new ones sit expectantly on the shelf.

Actually, I only change them when the shells get rusty. I have never had one wear out.

 

[airshot]

try these.. its what merc calls for... ngk buhw-2 are no more.

33-97182Q - NGK BUHW - 2 superseded to SPARK PLUGS (CHAMPION SPARK PLUGS) - L78V Sold individually.

Quicksilver has a new number as a replacement for the buhw-2 plugs, use that number to order plugs, but like I found out, the box containing the new plug numbers actually had the old buhw-2 plugs in the new boxes !

 

[Chris1956]

Gee, I used L-78V plugs in my '73 Merc 850. They are not new..... It looked like they had a slightly wider ground ring around the center electrode, compared to the BUHW or L-76V plugs.

 

[Texasmark]

Mark, do you have a listing for a conventional plug for a 1986 motor? I never saw one. Merc did specify conventional plugs for newer motors, however.

No sir. My manual is for 1996 through 2004+, 75 hp jets through125 conventional engines.