1975 20hp Mercury Blueband - correct plug type please - updated with serial number now

[Bronteboxer]

Can anybody tell me the correct plug specification for my 1975 20hp Mercury Blueband or what is now considered a suitable replacement please?

I don’t have my manuals to hand so sadly can’t do the proper check.

[Rapier]

What's the serial number?

[Rapier]

Normally L78V, but varies by serial no.

[Bronteboxer]

Me and the engine are in different places at the moment, so can’t get that right now.. I was just trying to source some whilst I had the time.

My recollection is the ones in there have quite a long number. BH at the front of the number? They have a single centre electrode.

[Bronteboxer]

At last I am back with my engine! So can post my serial number as requested for my Blueband 20hp it’s 9122768

Current plugs installed are BUHW-2

These are now obsolete. I have found some, but don’t want to order until I’m sure I’m buying the correct plug.

Any suitable quality alternatives anybody has experience of, given their lack of availability

Please can somebody help me on this, as I’m still stuck after all these years trying to get this old boat on the ruddy water.

[Rapier]

Champion L78V, or the Mercury EPC says AC Delco V40FFK.

Still around if you need them.

https://picclick.co.uk/?q=ngk+buhw-2&fi ... B%22%7D%7D

https://picclick.co.uk/?q=champion+l78V ... B%22%7D%7D

here's a cross ref link.

https://www.sparkplug-crossreference.co ... _PN/BUHW-2

[Bronteboxer]

Thanks. So assuming then that the plugs I listed are the correct plugs, (as I now have equivalents) I have managed to find a supplier. They are now obsolete and mostly out of stock. Luckily I’ve found some, so now ordered. Not really hopeful that it will solve the problem, but I need to eliminate them as an issue. Simple things first!