Correct spark plug for Mercury 25

charvett2 · #1 April 14th, 2005, 09:54 PM

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).

I think either one will work, but I'm wondering what it came from the factory with.

If it is the normal style plug, I'd also be curious as to the factory gap setting.

Thanks for any advice!

Mettaree · #2 April 15th, 2005, 06:01 AM

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

charvett2 · #3 April 15th, 2005, 11:45 AM

Thanks for looking that up JKW!

Hmm... That's interesting. Some of the other posts I've read seem to lean towards NGK as the standard for Mercury.

Does anyone else have any literature that suggests another type plug?

Thanks again for the help!

charvett2 · #4 April 16th, 2005, 10:30 AM

Bump...

charvett2 · #5 April 16th, 2005, 09:23 PM

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.

Does anyone know where or what Service Bulletin 91-36 is?

Thanks!

lakelover · #6 April 29th, 2005, 06:19 AM

achris · #7 April 29th, 2005, 07:26 AM

post your e-mail and I'll send you the service bulletin.

Chris...........

matsyk · #8 May 31st, 2005, 09:18 PM

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?