1987 Mercury 25 HP Spark Plug Recommendation

T

Tony.1

Recruit
Joined
Jul 7, 2008
Messages
2
What spark plug is currently recommended for a 1987 Mercury 25 HP outboard?

The current plugs have a gap of approx 0.080", which I suspect is at least a partial reason why the motor is very difficult to start.

The Operation & Maintenance Manual recommends NGK BUHW.
The previous owner of the boat/motor was using NGK BP8HS-10.
The NGK website and other websites recommend NGK BP8H-N-10.

Any advice would be appreciated.

Sincerely,
Tony
 
T

Tony.1

Recruit
Joined
Jul 7, 2008
Messages
2
Re: 1987 Mercury 25 HP Spark Plug Recommendation

I went with the NGK BP8H-N-10 plugs after continued research indicated they work better with today's blend of fuel; specifically the amount of ethanol used in fuel today. I've had the boat out about ten times since changing the plugs and the engine runs perfectly.

Tony
 
FISHINGMAN53

FISHINGMAN53

Cadet
Joined
Aug 29, 2012
Messages
15
WHAT ABOUT SURFACE GAP PLUG'S ANYONE EVER TRY THEM? FIRST, I SEEN EM AND BEEN TOLD THEIR USED IN MOTORCYCLES
 
R

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,288
??--Surface gap plugs.-------They were used in Johnson and Mercury outboards in the late 1960's
 
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