Seasonally changing Mercury 110 spark plugs

[dbclark52]

I just bought my first outboard boat and am starting to winterize it. I'm changing out my spark plugs with new and found that my motor (1975 Mercury 110 Thunderbolt) is using Autolite 7255 non-resistor plugs. My manual is saying I need Champion QL77JC4 or the NGK BR6HS plugs. It looks like the recommended plugs have resistors.

Im not familiar enough with two stroke outboards to know which I should go with. Gut tells me to go with Mercury's recommended plugs. Could someone enlighten me on non-resistor type plugs vs standard?

 

[matt167]

Resistor has to do with radio interference. Basically you’ll buzz an AM radio with non resistor plugs but not much else on the water.

 

[racerone]

When you buy one of those 9.8 motors you need to install a new water pump impeller.----Unless you have proof a new one was installed a month ago.

 

[dbclark52]

When you buy one of those 9.8 motors you need to install a new water pump impeller.----Unless you have proof a new one was installed a month ago.

First thing I did. Have a very good pee stream now. Thanks

 

[dbclark52]

Resistor has to do with radio interference. Basically you’ll buzz an AM radio with non resistor plugs but not much else on the water.

That makes sense. Could it interfere in any way with a fish finder? Not sure why they're there now. That's the reason I was going to replace with OEM recommendation. Was surprised to find them installed. Not knowing outboards I thought there might be a good reason for them.

 

[matt167]

I don’t think it’ll mess with a fish finder

 

[Texasmark]

Fish finders run on very low frequencies. Your outboard runs on 3x that range at idle and 30 times it at top end. If you get interference it would be little specks showing up on the display....something like little black or white dots spaced out, like when it starts snowing outside.

 

[racerone]

Sparkplugs should last years and years for the average user.

 

[airshot]

In my many years of boating, I have had better success with NGK or Quicksilver plugs in Mercury motors and better success with Champion plugs in OMC motors. However if motor runs and idles good and plugs are clean, why change them ? Whether it pees well or not, no way to know if that impeller is dry rotted and cracked. I would be more concerned with the water pump impeller than the spark plugs unless your having an issue...

 

[cyclops222]

A bad manufacturing run. Gives anything a bad name.