1987 Mercury 25 HP Spark Plug Recommendation

[Tony.1]

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

 

[Tony.1]

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]

WHAT ABOUT SURFACE GAP PLUG'S ANYONE EVER TRY THEM? FIRST, I SEEN EM AND BEEN TOLD THEIR USED IN MOTORCYCLES

 

[racerone]

??--Surface gap plugs.-------They were used in Johnson and Mercury outboards in the late 1960's

 

[roscoe]

Surface gaps in All my mercs.