'81 Tower Of Power sparkplugs.

AltheaToldMe

AltheaToldMe

Petty Officer 3rd Class
Joined
Jul 20, 2008
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78
This is a total newbie question, but here goes.

I was fooling around tonight with a fiberglass repair, so I decided to pull a couple of the plugs to look at. Much to my surprise, I found that the plugs did not look anything like a car plug. There is no hook at the end. They are flat as can be. There is a flat electrode and what looks like a washer ring around the bottom.

I have never seen a plug for this type of engine before, so I am not sure what I am looking at. They are NGK plugs. Is this something I should get used to?

Are there any plug recommendations for this engine? Are there performance plugs available or just standard?

Thanks in advance.
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,146
Re: '81 Tower Of Power sparkplugs.

Merc used the surface gap plugs for years. They last a long time in useage.

You should look up the year and model of your motor to get the correct ones. It would be surprizing to find a conventional plug for your motor. NGK and Champion make these plugs and they are available at most auto parts stores...
 
AltheaToldMe

AltheaToldMe

Petty Officer 3rd Class
Joined
Jul 20, 2008
Messages
78
Re: '81 Tower Of Power sparkplugs.

Chris1956 said:
Merc used the surface gap plugs for years. They last a long time in useage.
Click to expand...


So what are the advantages of these plugs? What are the disadvantages? Why does Mercury use this type of plug? Are there any settings (gap) that need to be checked?

Any information would be great!

Thanks!
 
J

jimg984

Chief Petty Officer
Joined
Jul 16, 2007
Messages
403
Re: '81 Tower Of Power sparkplugs.

longer life, much better firing surface, no gap setting ...dont have to worry about elctrode extending into cylinder in case of carbon build up on the piston
 
jimmbo

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,961
Re: '81 Tower Of Power sparkplugs.

A surface gap plug is an extremely cold spark plug and therefore much less likely to be a cause of preignition. One disadvantage, being so cold, is they are prone to fouling and need a strong ignition to make sure not only the voltage is high enough, but the voltage rise is fast enough so the plug fires a healthy spark instead of the voltage just bleeding away. Evinrude and Johnson also used these plugs during the late 60s and early 70s but went back to conventional plugs.
 
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