Three questions about installing spark plugs

[Mark Hofman]

I'm getting ready to swap out my spark plugs for a new set. Three questions:



First: How stupid would it be to simply try and clean the current plugs versus installing new plugs?



Second: If I have to go the new plug route, does anyone know what the recommended gap is on a NGK BU8H spark plug for a Mercury 150 XR6?



Third: How much torque should I apply when installing the new plugs?

 

[Rob LaMoy]

Mo, I recommend getting new ones, but keep your old ones and clean them off. Keep them in the boat as a spare set should you foul the ones in the motor. As for gap.....got me, I give up. How much?

 

[James D.]

the gap i think is listed on the motor plate label when you take off the cover of the motor.



jd

 

[Ken Neeley]

Call Craig for the gap....248-333-0997

 

[James D.]

i think i have read that you tighten them firmly by hand, then a quarter turn more. i replace mine each yr whether they need them or not. like rob, i keep the old ones for spares.

 

[Mike L.]

After the winter when re-opening the boat in the spring, start the engine and run it for a while using the old plugs. I like burning off the fogging oil with the old plugs, stop the engine and then install my new plugs....and like Rob says, keep the old ones in the boat as spares. Rotatingthis way I have new plugs every year and good ones for spares.

 

[Adam Murray]

If I remember correctly, those are gapless plugs. Just screw 'em in and go!

 

[Craig Roberts]

Adam is right. It's a "gapless" plug. Nothing to set. And keep your old plugs. First time you start her up after winterizing, put the "old" plugs in and let them foul up. Then put your new plugs in after burning off the fogging oil.



Craig

 

[James D.]

learn something new everyday. what is a gapless plug? do you mean the gap is "pre set" or is this a new type.



jd

 

[Adam Murray]

Kinda like a centerfire rifle (not really, but for some reason I always relate the two). There's no armature and spark shoots straight into the cylinder.



Craig will have to provide the technical assessment...

 

[Craig Roberts]

Try this link.



Craig




http://ngksparkplugs.com/products/marine/outboardsurfacedis.asp

 

[gone bye bye]

I thought they were gapless too...



Mini

 

[Staci Matheis]

Re: Torque.....



Mark, if it'll help, I'll come over and put them in for you! My wrist is calibrated to tighten spark plugs precisely!



me!

 

[James D.]

thanks adam and craig. i'll check them out. my little 115hp merc has the older traditional type with the gap. i've also heard to run only ngk plugs in a mercury motor as they run either hotter or cooler than other companies plugs. it looks like from the ngk site that there is only one particular plug listed for each motor.

 

[Staci Matheis]

Bob, Bob, Bob..... You shouldn't have done that..... You know how anal Mark can be..... Now he'll go out and buy two torque wrenches..... The first in ft/pounds..... And a second in inch/pounds..... Just to be absolutely sure-for-certain that he gets them down EXACTLY RIGHT!



:^)

me!

 

[Mark Hofman]

Scott, how'd you know I'd be at Sears this morning????

 

[Staci Matheis]

.....and predictable, too!