Correct spark plug for Mercury 25

charvett2

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Mar 9, 2004
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I have a 1988 Mercury 25 2 Stroke (SN B267056) and the current spark plugs that's in it is an NGK BUHW (gapless style), but I have seen it listed online as also taking an NGK BP8H-N-10 (extended tip).<br /><br />I think either one will work, but I'm wondering what it came from the factory with.<br /><br />If it is the normal style plug, I'd also be curious as to the factory gap setting. <br /><br />Thanks for any advice!
 

Mettaree

Petty Officer 1st Class
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May 17, 2003
Messages
292
Re: Correct spark plug for Mercury 25

My Seloc manual shows a Champion L76V surface gap plug for that motor.
 

charvett2

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Mar 9, 2004
Messages
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Re: Correct spark plug for Mercury 25

Thanks for looking that up JKW!<br /><br />Hmm... That's interesting. Some of the other posts I've read seem to lean towards NGK as the standard for Mercury. <br /><br />Does anyone else have any literature that suggests another type plug?<br /><br />Thanks again for the help!
 

charvett2

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Mar 9, 2004
Messages
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Re: Correct spark plug for Mercury 25

OK, did a little more digging and the Mercury parts site lists a handful of different plugs for my model. I refers to Service Bulletin 91-36 but doesn't say what it is.<br /><br />Does anyone know where or what Service Bulletin 91-36 is?<br /><br />Thanks!
 

achris

More fish than mountain goat
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May 19, 2004
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27,468
Re: Correct spark plug for Mercury 25

post your e-mail and I'll send you the service bulletin.<br /><br />Chris...........
 

matsyk

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May 27, 2005
Messages
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Re: Correct spark plug for Mercury 25

Sorry about bumping this topic but it the closest to my question. I also have a 1988 25 HP Merc. Mercury Marine Canada recommended that I use a NGK BPZ8H-N-10 plug because of our water temps and the requirement for a resistor type plug, but like an idiot I forgot to ask for the gap. Anybody happen to know it?
 
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