1975 evinrude 40 hp

[redssteelers]

I just bought a pontoon boat with an evinrude 1975 40 hp 40555c. It has a j8c sparkplug in it, but according to evinrude site the correct plug is ul81c. Will this plug be to hot, since the heat range is 81 compared to 8 thats in the motor now

 

[JB]

Re: 1975 evinrude 40 hp

Howdy.

Welcome to iboats.

I think the J8C is too hot for that motor. Use what Champion plug that OMC calls for. Ignore any and all spark plug application charts (they are loaded with errors) and obey the Owner's manual. Champion UL81C gapped at .030" sounds good to me.

 

[redssteelers]

Re: 1975 evinrude 40 hp

Howdy.

Welcome to iboats.

I think the J8C is too hot for that motor. Use what Champion plug that OMC calls for. Ignore any and all spark plug application charts (they are loaded with errors) and obey the Owner's manual. Champion UL81C gapped at .030" sounds good to me.

Thanks for the info JB. I wonder would the j8c cause the motor to not want to idle good? Have replaced coils (crakced) also cleaned the carb and replaced fuel lines, bulb and tank. Comimg into my slip at low rpm the motor dies will crank right back, but doesn't want to run at low rpm. On open water the motor will push the 20 ft. pontoon at 19 mph. Runs good on open water. James