Resistance/non-resistance plugs

[Boat_Boy!]

The manual for my 1992 Yamaha C40 calls for two different plugs. One is the "plug cap without resistance (NGK # B8HS) the other is "plug cap with resistance" (NGK # BR8HS). What does this mean? Are there two types of plugs I can use, or are they saying that I use two DIFFERENT plugs at the same time? What do they mean by saying "plug cap with/without resistance.<br /><br />Just a beginner!<br /><br />------------------<br />Boat_Boy!

 

[12Footer]

Re: Resistance/non-resistance plugs

Resistive plugs cut-down on RFI (Radio Frequency Interference).<br />If you run a trolling motor,FM radio,VHF radio or CB, you no doubt have heard your engine trying to broadcast it's dulcet tones.<br />If you have no electronics, or RFI is not a problem, go with the non-resistive plugs.<br />The benifits are less fouling,but at the expense of more noise.

 

[12Footer]

Re: Resistance/non-resistance plugs

All that, and I forgot to say,iether plug set will work fine on your engine. Non-resistive will just emitt more RFI.

 

[Boat_Boy!]

Re: Resistance/non-resistance plugs

Thanks for your advice.<br /><br />------------------<br />Boat_Boy!

 

[fone_man]

Re: Resistance/non-resistance plugs

Check out NGK site.... & will tell you all about these plugs<br /> http://www.ngksparkplugs.com/apps/watercraft/ <br /><br />

<br /><br />------------------<br />"Keep It Between The Bouys" & "Good Luck"!!!<br /><br />fone_man

 

[alpapale]

Re: Resistance/non-resistance plugs

Boat_boy,<br /><br />What 12Footer says about the resistor plugs vs. non resistor plugs is correct. The non-resistor plug will generate more RFI (radio frequency interference). The thing to keep in mind, however, is that in some applications electronic ingnitions can have sensitive electronics integrated within them and a non-resistor type plug could generate enough RFI to effect it, causing more problem then just noise on you radio or VHF. If your application called for either, then you're good to go with either one. They may however call for a different spark plug "gap" setting. I think maybe this is what you meant when you asked about, "plug cap"; did you mean plug gap??

 

[Boat_Boy!]

Re: Resistance/non-resistance plugs

No kidding. The manual actually says "cap" and no listing is provided for different gaps for the two types of plugs. The manual says the gap should be 0.20 to 0.24 for both plug types.<br /><br />------------------<br />Boat_Boy!

 

[alpapale]

Re: Resistance/non-resistance plugs

The resistive material in the spark plug itself is located within the white ceramic insulator. They use a carbon material for resistive or a conductor (i.e. copper) for high performance plugs. (Today, I'm sure they figured a way to make a resistive plug that they can call "copper" or whatever.) Maybe there refering to the insulator portion of the plug as the cap?<br /> who knows.<br /><br />Happy boating!<br /><br />alpapale

 

[fone_man]

Re: Resistance/non-resistance plugs

Here you go..........<br /><br />1992 YAMAHA 40 40.0 hp 3 Cyl.<br /><br />Spark Plug Part No. Stock No. Plug Gap <br />Standard B7HS-10 # 2129 # .039 <br /><br />---------------------------------------------<br /><br />Standard & Resistor<br />The workhorse, at the heart of smooth-running engines around the world. Available in standard or resistor.<br /><br />OEM Quality <br />Triple-Gasket Sealing Process <br />Consistent Performance <br />Plug of Choice in Millions of Vehicles <br /> <br /><br />Inductive Resistor Spark Plugs<br />Specified as original equipment in a variety of late-model outboard engines, spark plugs with an inductive resistor are utilized when a CDI (capacitive discharge ignition) system is used. The resistor plug is necessary to reduce radio frequency interference (RFI), to prevent interference with the sophisticated electronics onboard modern boats.<br /><br />Most resistor spark plugs use a "monolithic" resistor, generally made of graphite and glass materials, to filter the electrical voltage as it passes through the center electrode. This "filter" reduces RFI to an acceptable level. Although this type of resistor develops from 1000 to 5000 ohms of resistance, there is no significant loss of voltage to affect ignitability at the electrodes in modern automotive ignition systems.<br /><br />However, outboard marine engines utilizing a CDI system have a much lower voltage output, which would be compromised by a standard resistor plug. Therefore, an inductive resistor is used. In this method, a coiled nickel wire is inserted into the center stem, and held in place by a spring.<br /><br />This coil basically acts as an electromagnet, inducing a magnetic field around the center stem, creating a natural "field" resistor, and reduces RFI to acceptable levels. This method creates only 40 ohms of physical resistance, compared to the 1000 to 5000 ohms of resistance in "monolithic" resistor plugs.<br /><br />While NGK Inductive Resistor Spark Plugs cost more than standard resistor plugs, they provide major benefits in late-model marine outboard applications. <br /><br /><br /><br />------------------<br />"Keep It Between The Bouys" & "Good Luck"!!!<br /><br />fone_man

 

[alpapale]

Re: Resistance/non-resistance plugs

Hey fone-man,<br /><br />Good information. I did'nt know they got so sophisticated with these plugs. What do you recommend as a rplacemend for a 2001 Volvo-penta 4.3 I/O? (It's really a GM block as you know) Should I just look up what NGK lists as a replacement. Can I upgrade to the inductive type if their replacement doesn't call for it? Should I?<br /><br />Thanks!

 

[fone_man]

Re: Resistance/non-resistance plugs

You might want to OEM in them... which is probably AC/Delco<br /><br />You might want to vist here... http://www.gmpowertrain.com/engines_marine/43_main.htm <br /><br />c-ya<br /><br />

<br /><br />------------------<br />"Keep It Between The Bouys" & "Good Luck"!!!<br /><br />fone_man