470 Spark Plugs

N

noralogdog

Cadet
Joined
May 31, 2012
Messages
9
The original manual for my 83 470 lists only two spark plugs that could be used. AC-Delco and Champion. Is there an NGK plug I can use for this engine. I think this might be a better plug. If not, which of the other two are better. Hmmm, I wonder how many will agree on this one?
 
Eric 3.7LX Alpha 1

Eric 3.7LX Alpha 1

Captain
Joined
Mar 27, 2010
Messages
3,008
Re: 470 Spark Plugs

Service manual 3 shows 4 different plugs, I use NGK or AC Delco, right now have the Delco's and it's running perfect. Champion are for lawn mowers.

BTW... the timing has been changed from 8? to 4? in a TSB since the manual.
 

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N

noralogdog

Cadet
Joined
May 31, 2012
Messages
9
Re: 470 Spark Plugs

Eric 3.7LX Alpha 1 said:
Service manual 3 shows 4 different plugs, I use NGK or AC Delco, right now have the Delco's and it's running perfect. Champion are for lawn mowers.

BTW... the timing has been changed from 8? to 4? in a TSB since the manual.
Click to expand...

Thanks. This helps a lot. Do you know why they changed the timing? I adjusted my timing recently and went by the 8 degree. The engine runs fine. Would it improve set at 4?
 
wrestling coach

wrestling coach

Petty Officer 1st Class
Joined
Jun 27, 2011
Messages
210
Re: 470 Spark Plugs

NGK plug is BPR6FS gapped .035 if on points ignition or .040 if on Pertronix. I prefer these plugs in my 470 and use them in my 90 Johnson 2 stroke. I can troll all day with the 2 stroke and never skip a beat.

Dennis
 
nola mike

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,072
Re: 470 Spark Plugs

noralogdog said:
Thanks. This helps a lot. Do you know why they changed the timing? I adjusted my timing recently and went by the 8 degree. The engine runs fine. Would it improve set at 4?
Click to expand...

They changed it because of concerns over the quality of fuel and detonation at the higher setting.
 
L

lselmes

Seaman Apprentice
Joined
Sep 21, 2006
Messages
31
Re: 470 Spark Plugs

6 Degrees BTDC seems to be the preferred setting with guys running Pertronix ignition and Flamethrower coil as well as .040 on plug gap as stated above. I run this set-up on my Glasply with NGK's and have never looked back. My 81 470 runs smooth as silk and sips gas running at 3000 rpm / 27mph.
 
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