Which spark plugs?

[eurolarva]

I have a 67 45hp chrysler Mdl 45781. I bought the motor 3 years ago and the plugs on the motor are Champion RL86C. I went to Twin City Outboard today to get new plugs and I forgot my book. They looked up and sold me Champion RJ12C plugs. When I got home the manual calls for L4J plugs. Not sure what to do. Noticed the plugs in the boat seem to foul at least twice a year. Should I use the new RJ12C plugs? Or try and get the L4J plugs that show in the book.

 

[Hooty]

Re: Which spark plugs?

Personally, I use what the manual specs, have for 40+ years and it works for me.<br /><br />c/6<br /><br />Hooty

 

[scotiany]

Re: Which spark plugs?

You're not going to find the L4J anymore. Do a search in this forum for Chrysler spark plug. I'm pretty sure it was replaced by the L82C. Resistor plugs in your engine are not a good idea.

 

[eurolarva]

Re: Which spark plugs?

Thanks for the reply Scotiany. Found something on last search on chrysler. Says that NGK B6HS is a good cross reference and someone said L82C has been working well for them. I thought the resistor was to prevent harmonics from engine on my electronic equipment. Wont the L82C cause noise on my Graph? Does the resister in the plug cause less spark?

 

[Boatist]

Re: Which spark plugs?

eurolarva<br />I have been useing the non resistor plugs for a long time and had no trouble with depthfinder, Loran C, GPS, VHF radios. My 75 Johnson crosses to the Champ L82C. The L86C is one heat range hoter and the L90C is two heat ranges hotter. I have been useing the L90C for many years in my trolling motor and had a lot fewer fouled plugs but then I never run it wide open.

 

[eurolarva]

Re: Which spark plugs?

Been getting all kinds of spark plug numbers and am worried if I put the wrong ones in I could hurt the motor. Did all kind of searches to find the replacement for the L4J and could not find one. I found a good NGK site and would like to share it. Wish champion had one. Maybe they do but I am not using the correct words for the search. The ngk site actually goes to specific marine motor and year. Here is the link. Hope someone finds it useful<br /><br /> http://www.ngksparkplugs.com/index2.asp?country=US&nav=a0000