resistor type spark plugs or not?

[ronaldhase]

I have a late 90's model tohatsu m40d
the book says to use ngk BR7HS or champion RL82C
but the sticker on the engine says use B7HS or L82c
how do I know if I have the right plugs?

 

[MattFL]

I would go with the resistor plug. It will be less noisy (electrically speaking), which means less potential interference with your cell phone, GPS, etc.. Here's a quote from the NGK web site, and a link to the full article:

Global Networks｜NGKスパークプラグ/NTKテクニカルセラミックス製品サイト

NGKスパークプラグ／NTKテクニカルセラミックス製品サイトの「Global Networks」ページです。

www.ngk-sparkplugs.jp

As the resistor spark plug has an incorporated resistor, some people think that it has adverse effects on start-up, acceleration, fuel economy and emissions. However, this is wrong. It does not affect engine performance so don't hesitate to use it.

 

[ahicks]

After learning the hard way, I agree with Matt.

I had a flat spot in a 40hp Johnson make me nuts for most of a summer a few years ago. To keep this as short as possible, the issue turned out to be the non resistor spark plugs emitting noise that was affecting the engine's ignition power pack - causing a miss fire at 4500 rpm. Installing resistor plugs, with no other changes, fixed the problem. No more non resistor plugs for me - ever! -Al

 

[Sea Rider]

Both are the right spark plugs type whether with resistor or not, the ignition coil spark plug's booths as well counts with internal resistors...

Happy boating​