1973 Evinrude 25 hp.... HELP

S

soccerdan90

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Apr 8, 2012
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I just traded a guy my jet ski for his 16 ft flat bottom boat and this 25 hp outboard. He gave me some cash on top so it was a pretty good deal. Anyways I was in the process of changing spark plugs and making sure the correct ones were installed. Well the ones on it are Champions J6C, on sparkplugs.com it says they should be J8C, and on another chart it says it should be J4C. I have no idea what to use. The motor barely runs and the spark plugs are so fouled that it could be the problem. I want to install the proper plugs so that I can rule that out or possibly fix it. Could having the wrong size plug cause me permanent damage? Thanks in advance.
 
JB

JB

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Re: 1973 Evinrude 25 hp.... HELP

Howdy, Dan

Welcome to iboats. :)

The original specified plugs were Champion J4J (now J4C). Over the years they showed some tendency to foul if idled or trolled for long periods, so many guys went to the J6C. I would still prefer the J4C for all-round use, but for lots of trolling I would use the J6C.

Either will work gapped at .030".

J8C is too hot for that outboard. It is a lawn mower plug and could cause piston damage.
 
S

soccerdan90

Cadet
Joined
Apr 8, 2012
Messages
15
Re: 1973 Evinrude 25 hp.... HELP

JB said:
Howdy, Dan

Welcome to iboats. :)

The original specified plugs were Champion J4J (now J4C). Over the years they showed some tendency to foul if idled or trolled for long periods, so many guys went to the J6C. I would still prefer the J4C for all-round use, but for lots of trolling I would use the J6C.

Either will work gapped at .030".

J8C is too hot for that outboard. It is a lawn mower plug and could cause piston damage.
Click to expand...

Thanks for the response. I will be using it to go up and down the river to check diddy poles and to get to fishing spots. Mainly using full power. I will just use the J4C if thats what was originally preffered. Thanks for the help.
 
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