'04 15 hp spark plugs

[trebot]

The NGK site calls for BPZ8HS-15 plugs. Motor has BPZ8HS plugs installed and gap at .040. 2 questions: What does the " -15 " mean? Motor data calls for .060 gap. I've never seen a plug gap this wide. Should I stay with the .040 gap or go .060?

 

[hardwater fisherman]

According to the NGK website the -15 stands for 1.5mm ( .0 59" ) gap.

 

[tommarvin]

What made you check your spark plugs? New motor to you?
Is there something wrong with your motor?
We remove our plugs and clean all the carbon off the threads, the grounding electrode, body, tooth brush small wire brush works great.
You can test your plugs with a multi meter, is the resistance on all the plugs very close to same set on 20K ohms setting? Like 4.3- 4,6.
Is your motor EFI or carbs.