Spark Plugs NGK B7HS- NGK B7HS-10

[laker]

I have a 1992 40Hp Yamaha and I used spark plugs NGK b7HS and it calls for NGK B7HS-10 whats the difference?

 

[matt2002]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

The -10 is important.Did you see them on your old plugs ?

 

[laker]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

Yes I saw them on the old plugs I just now noticed the new didnt have it. Will I loose horse power or performance? Thanks

 

[matt2002]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

Make sure the -10 is either on the box or the plug itself.

 

[Dunaruna]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

No need to panic, it's not critical. B7HS has a factory set gap of 0.8mm. B7HS-10 has a factory set gap of 1.0mm.

We are talking about a difference of 8 or 9 thou. Get out the feeler gauges and open the gap to 1.0mm (40 thou).

 

[laker]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

Thanks so It really doesnt matter what plug I use right?

 

[Dunaruna]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

Not really. The -10 plug has a slightly longer ground electrode but we are only talking 0.2 mm. You can easily open the gap but the electrode will be on a very slight angle (almost undetectable by the eye). It will work fine but next time buy the -10.

 

[BruceAML]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

It would help if you posted the exact model number of your motor as some 40 hp motors take a B8HS spark plug. Yes it does make a difference to have the correct spark plug.

 

[laker]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

model # 423765 serial # 40ELRQ thanks

 

[BruceAML]

Re: Spark Plugs NGK B7HS- NGK B7HS-10

The correct spark plug for your motor is a Yamaha part number NGK-B7HS1-00-00 which is an NGK B7HS-10 with a gap of 0.9 mm/.035 in.